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CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is based upon and claims the benefit of priority under 35 U.S.C. § 119 from prior Japanese Patent Application 2004-279914 filed on Sep. 27, 2004; the entire contents of which are incorporated by reference herein. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] Exemplary embodiments of the present invention relate to a display apparatus and an information terminal with a display device, such as a Liquid Crystal Display (LCD). [0004] 2. Description of the Background [0005] The use of an information terminal with a LCD, such as a notebook PC, has become more and more common these days. [0006] However, in connection with the increase in use, dropping of the information terminal has also increased. As a result of dropping the terminal, the LCD of the information terminal can become damaged. [0007] In an effort to reduce damage to the LCD, others have inserted some shock absorbing material between a case and the LCD of the information terminal. In an example of an information terminal having a case and a LCD, a hinge is connected by screws to the LCD unit and a protection base. This technique prevents directly transmitting shock from a main body to the LCD. However, this technique is insufficient because the screw connects the case and the LCD rigidly. Accordingly, shock is transmitted to the LCD through the screw (see, e.g., JP-A-2004-4721). [0008] The related art also includes forming a shock absorbing material like a frame around the LCD. That is, the inner size of the shock absorbing material is designed smaller than an outer size of the LCD, and the LCD is fitted into the inner side of the shock absorbing material. This technique prevents transmission of a shock from the main body to the LCD well. According to this technique, the shock absorbing material fills a gap between the case and the LCD, and strongly cramps the LCD to the case. However, much effort is required to press the shock absorbing material into the gap between the LCD and the case making assembly difficult (see, e.g., JP-A-2001-183634). BRIEF SUMMARY OF THE INVENTION [0009] Accordingly, an object of the present invention is to provide a display unit that can survive being dropped and can be easily assembled. [0010] According to an exemplary embodiment, one aspect of the invention is a display apparatus including a display unit configured to display an image; a shock absorbing elastic body configured to contact the display unit; a press member configured to press against the elastic body; and a catch member configured to secure the press member. The elastic body absorbs shock transferred from the catch member to the press member. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0011] The invention and attendant advantages therefore are best understood from the following description of the non-limiting embodiments when read in connection with the accompanying Figures, wherein: [0012] FIG. 1 illustrates a perspective view of a notebook PC; [0013] FIG. 2 illustrates a sectional view of a display section in a plane parallel to a display face of a LCD unit according to a first exemplary embodiment; [0014] FIG. 3 illustrates a sectional view of a section near a screw hole and a screw according to a first exemplary embodiment; [0015] FIG. 4 illustrates a sectional view of a display section in a plane parallel to a left side face of a LCD unit according to a first exemplary embodiment; [0016] FIG. 5 illustrates a sectional view of a display section in a plane parallel to a display face of a LCD unit, without a roll off, according to a first exemplary embodiment; [0017] FIG. 6 illustrates a sectional view of a section near a screw hole and a screw, without a roll off, according to a first exemplary embodiment; [0018] FIG. 7 illustrates a sectional view of a display section in a plane parallel to a side face of a LCD section, without a roll off, according to a first exemplary embodiment; [0019] FIG. 8 illustrates a sectional view of a display section in a plane parallel to a display face of a LCD unit according to a second exemplary embodiment; [0020] FIG. 9 illustrates a sectional view of a section near a screw hole and a screw according to a second exemplary embodiment; [0021] FIG. 10 illustrates a sectional view of a display section in a plane parallel to a display face of a LCD unit according to a third exemplary embodiment; [0022] FIG. 11 illustrates a sectional view of a display section in a plane parallel to a side face of a LCD unit according to a third exemplary embodiment; [0023] FIG. 12 illustrates a sectional view of a display section in a plane parallel to a display face of a LCD unit according to a fourth exemplary embodiment; [0024] FIG. 13 illustrates a sectional view of a display section in a plane parallel to a display face of a LCD unit according to a fifth exemplary embodiment; [0025] FIG. 14 illustrates a sectional view of a display section in a plane parallel to a display face of a LCD unit according to a sixth exemplary embodiment; [0026] FIG. 15 illustrates a sectional back view of a display section in a plane parallel to a display face of a LCD unit according to a sixth exemplary embodiment; [0027] FIG. 16 illustrates a sectional view of a display section in a plane parallel to a side face of a LCD unit according to a sixth exemplary embodiment; [0028] FIG. 17 illustrates a perspective sectional view of the display section according to a seventh exemplary embodiment; [0029] FIG. 18 illustrates a sectional view of a display section in a plane parallel to a side face of a LCD unit according to a seventh exemplary embodiment; [0030] FIG. 19 illustrates a perspective sectional view of the display section according to an eighth exemplary embodiment; [0031] FIG. 20 illustrates a sectional view of a display section in a plane parallel to a display face of a LCD unit according to a ninth exemplary embodiment; [0032] FIG. 21 illustrates a sectional view of a section near a screw hole and a screw according to a ninth exemplary embodiment; [0033] FIG. 22 illustrates a sectional view of a display section in a plane parallel to a display face of a LCD unit according to a tenth exemplary embodiment; [0034] FIG. 23 illustrates a sectional view of a section near a screw hole and a screw according to a tenth exemplary embodiment; [0035] FIG. 24 illustrates a sectional view of a display section, before pressing a side rubber, in a plane parallel to a side face of a LCD unit according to an eleventh exemplary embodiment; [0036] FIG. 25 illustrates a sectional view of a display section, in which a pad presses a side rubber, in a plane parallel to a side face of a LCD unit according to an eleventh exemplary embodiment; [0037] FIG. 26 illustrates a sectional view of a display section in a plane parallel to a display face of a LCD unit according to a twelfth exemplary embodiment; [0038] FIG. 27 illustrates a exploded view of a display according to a twelfth exemplary embodiment; and [0039] FIG. 28 illustrates a sectional view of a section near a screw hole of a screw support member and a screw. DETAILED DESCRIPTION OF THE INVENTION [0040] Referring now to the Figures in which like reference numerals designate identical or corresponding parts throughout the several views. First Exemplary Embodiment [0041] FIG. 1 illustrates a perspective view of an example of a first non-limiting embodiment of a notebook PC 1 according to the invention. [0042] The notebook PC 1 includes a main body 2 , a hinge 3 , and the display section 100 having a LCD unit 101 . The main body 2 has a keyboard, a click button, etc. [0043] The main body 2 processes data inputted by a user using the keyboard and the click button, and outputs image data for presenting to the user according to the processing. [0044] The hinge 3 supports the display section 100 turnably to the main body 2 . The display section 100 displays an image according to the image data from the main body 2 . [0045] FIG. 2 illustrates a sectional view of the display section 100 in a plane parallel to a display face 1011 of the LCD unit 101 . The display section 100 includes the LCD unit 101 as a display unit, the case 102 as a catch member or a housing, a side rubber 103 as an elastic body, and a screw 104 as a press member. [0046] The elastic body such as the side rubber 103 and other rubbers described below may be made from not only rubber but also foamed body such as urethane or other well-known elastic material. [0047] The LCD unit 101 has an outer frame formed with material such as glass or plastics. [0048] The LCD unit 101 has the display face 1011 . The LCD unit 101 displays the image, according to the image data from the main body 2 , in a displaying area 1012 formed at the front of the LCD unit 101 . [0049] Four faces such as a LCD top face 1014 , a LCD right side face 1015 , an LCD bottom face 1016 and a LCD left side face 1017 (they are collectively called LCD side faces 1013 ), have a some thickness, and support a pressure from the side rubber 103 . The case 102 is a case for protecting the LCD unit 101 . [0050] The case 102 covers the side rubber 103 and the display face 1011 except the displaying area 1012 . The case 102 , as a housing, comprises a hinge joint 201 , a LCD housing space 202 , and a screw hole 203 . The hinge joint 201 rotatably connects with the main body 2 . The LCD housing space 202 is formed inside of the case 102 . Inside side faces of the case 1023 are inner faces of the LCD housing space 202 facing to the LCD side faces 1013 . The LCD housing space 202 houses the LCD unit 101 and the side rubber 103 . [0051] The screw hole 203 has a spiral corresponding to the screw 104 , and is through the case 102 . The screw hole 203 connects the outside of the case 102 and the LCD housing space 202 . [0052] The screw hole 203 is formed on each of inside side faces of the case 1023 . Each of screw holes 203 is respectively substantially perpendicular to the LCD side faces 1013 in depth. The side rubber 103 has side rubber contact sections 1031 that contacts the LCD side faces 1013 . The side rubber 103 also has a side rubber press section 1032 which contacts the screw 104 , behind the side rubber contact section 1031 . [0053] The screw hole 203 faces the side rubber press section 1032 . A thrust of the screw 104 transmits to the side rubber contact section 1031 . The side rubber 103 is formed like a frame surrounding the LCD unit 101 . [0054] The side rubber 103 is placed in the gap between the LCD unit 101 and inside side faces of the case 1023 . The side rubber 103 is provided to cushion a shock given to the LCD unit 101 from the case 102 . All the side rubber contact sections 1031 contact the LCD unit 101 . [0055] As the result, shaking of the LCD unit 101 can be absorbed, and a stress can be spread to each side rubber contact sections 1031 when an impulse force or shock is added on the case 102 . [0056] There is a roll off 1033 between each of side rubber contact sections 1031 . The side rubber 103 is deformed along the direction parallel to one of LCD side faces 1013 facing to the roll off 1033 by the thrust of the screw 104 . The roll off 1033 is a buffer for the deformation of the side rubber contact section 1031 . Accordingly, the side rubber 103 can be deformed. The screw 104 is screwed in the screw hole 203 of the case 102 from the outside of the case 102 . [0057] FIG. 3 illustrates a sectional view of a section near the screw hole 203 and the screw 104 . The screw head 1041 of the screw 104 is buried into a counter boring 1021 bored at the outside of the case 102 . The counter boring 1021 is covered by a seal cover 1022 so that the screw head 1041 cannot be seen from the outside of the case 102 . [0058] A tip of the screw 104 contacts the side rubber press section 1032 . The tip of the screw 104 screwed in the screw hole 203 presses and deforms the side rubber 103 . Accordingly, energy transferred from the case 102 can be absorbed. As a result, bounce is produced between the case 102 and the LCD side faces 1013 , and all the side rubber contact sections 1031 contact LCD side faces 1013 . [0059] If a screw 104 is directly screwed in the LCD unit 101 to produce a tension between the case 102 and the LCD side faces 1013 for contact of the side rubber 103 , when an impulse force is added on the case 102 , the screw 104 concentrates and transmits the impulse force that can destroy the LCD unit 101 . In contrast, the display section 100 in this exemplary embodiment has such a structure to use the shock absorbing elastic body for supporting the LCD unit 101 . Accordingly, the LCD unit 101 can survive being dropped and be protected from the impulse force or shock transmitted from the case 102 . [0060] FIG. 4 illustrates a sectional view of a display section 100 in a plane parallel to the LCD left side face 1017 of the LCD unit 101 . The case 102 covers the front rubber 105 and the display face 1011 except the displaying area 1012 . A portion around the displaying area 1012 on the display face 1011 supports a pressure from a front rubber 105 . [0061] A LCD back face 1018 that is behind the display face 1011 supports a pressure from a back rubber 108 . [0062] The LCD housing space 202 houses the front rubber 105 and the back rubber 108 . An inside front face of the case 1025 is an inner face of the LCD housing space 202 facing to the display face 1011 . An inside back face of the case 1028 is an inner face of the LCD housing space 202 facing to the LCD back face 1018 . The inside front face of the case 1025 has an opening at a position facing to the displaying area 1012 . [0063] The screw hole 203 of the inside front face of the case 1025 is substantially perpendicular to the LCD front face 1025 in depth. A plurality of screw holes 203 are formed in line parallel to four sides of the inside front face of the case 1025 . [0064] The screw hole 203 of the inside back face of the case 1028 is substantially perpendicular to the LCD back faces 1018 in depth. A plurality of screw holes 203 are formed in line parallel to four sides of the inside back face of the case 1028 . The front rubber 105 is formed to support the display face 1011 . The front rubber 105 has an opening at a position facing the displaying area 1012 . [0065] The front rubber 105 is placed in the gap between the display face 1011 and the inside front face of the case 1025 . The front rubber 105 cushions a shock given to the LCD unit 101 from the case 102 . [0066] The front rubber 105 has front rubber contact sections 1051 which contacts the LCD unit 101 . All front rubber contact sections 1051 contact the LCD unit 101 . As a result, shaking of the LCD unit 101 can be absorbed, and a stress can be well spread to each front rubber contact sections 1051 when an impulse force or shock is added on the case 102 . The front rubbers 105 have a front rubber press section 1052 which contacts the screw 104 , behind the front rubber contact section 1051 . The back rubber 108 is formed to support the LCD back face 1018 . The back rubber 108 is placed in the gap between the back face 1018 and the inside back face of the case 1028 . The back rubber 108 cushions a shock given to the LCD unit 101 from the case 102 . The back rubber 108 has back rubber contact sections 1081 that contacts the LCD unit 101 . All back rubber contact sections 1051 contact the LCD unit 101 . As the result, shaking of the LCD unit 101 can be absorbed, and stress can be spread to each back rubber contact sections 1081 when an impulse force is added to the case 102 . The back rubbers 108 have a back rubber press section 1082 which contacts the screw 104 , behind the back rubber contact section 1081 . There is a roll off 1083 between back rubber contact sections 1081 . The back rubber 108 is deformed along the direction parallel to one of LCD back faces 1018 facing the roll off 1083 , by the thrust of the screw 104 . The roll off 1083 is a buffer for the deformation of the back rubber contact section 1081 . As such, the back rubber 108 can be resiliently deformed. [0067] The tip of the screw 104 screwed in the screw hole 203 of the inside front face of the case 1025 presses and deforms the front rubber 105 . As the result, shock is absorbed from the case 102 and all the front rubber contact sections 1051 contact the LCD unit 101 . The tip of the screw 104 screwed in the screw hole 203 of the inside back face of the case 1028 presses and deforms the back rubber 108 . As the result, bounce is produced between the case 102 and the LCD back face 1018 , and all the back rubber contact sections 1081 contact the LCD unit 101 . [0068] According to this exemplary embodiment, all contact sections of all rubbers can contact the LCD unit 101 , so all rubbers can cushion a shock given to the LCD unit 101 from the case 102 . Furthermore, because rigid body contacts the LCD unit 101 , shock will not transfer to the LCD unit 101 without being cushioned by rubbers. Accordingly, the effects of shock on the LCD unit 101 can be reduced. Additionally, it is not necessary for rubbers to be compressed greatly when being inserted into the gap between the LCD unit and the case. Accordingly, the display section 100 can be assembled very easily. [0069] In addition, it is possible to form rubbers without roll offs if elasticity of rubbers can be assumed after compressing rubbers with screws, as shown in FIG. 5 , FIG. 6 , and FIG. 7 . Second Exemplary Embodiment [0070] FIG. 8 illustrates a sectional view of the display section 100 in a plane parallel to the display face 1011 of the LCD unit 101 in this exemplary embodiment. In this exemplary embodiment, the case 102 does not have screw holes. But there is a frame 204 as a catch member or a housing, which has screw holes 203 , in the LCD housing space 202 . [0071] The frame 204 may be made from a light metal, such as a magnesium alloy and an aluminum alloy. The frame 204 has frame outer walls 2044 facing to the LCD housing space 202 of the case 102 , and frame inner walls 2045 facing to the LCD unit 101 . Frame inner walls 2045 surround a LCD housing space of the frame 2042 . The LCD housing space of the frame 2042 houses the LCD unit 101 and the side rubber 103 . Frame inner walls 2045 have screw holes 203 . [0072] Screw holes 203 have a spiral corresponding to the screw 104 , and are through frame inner walls 2045 . Screw holes 203 are formed on each of frame inner walls 2045 . Each of screw holes 203 are respectively perpendicular to the LCD side faces 1013 in depth. The side rubber 103 has side rubber contact sections 1031 that contacts the LCD side faces 1013 . The side rubber 103 also has a side rubber press section 1032 that contacts the screw 104 , behind the side rubber contact section 1031 . [0073] The screw hole 203 faces the side rubber press section 1032 . A thrust of the screw 104 transmits to the side rubber contact section 1031 . The side rubber 103 is formed like a frame surrounding the LCD unit 101 . The side rubber 103 is placed in the gap between the LCD unit 101 and frame inner walls 2045 surrounding the LCD housing space of the frame 2042 . The side rubber 103 cushions a shock given to the LCD unit 101 from the frame 204 . All the side rubber contact sections 1031 contact the LCD unit 101 . As a result, shock from the shaking of the LCD unit 101 can be absorbed, and stress is well spread to each side rubber contact sections 1031 when an impulse force or shock is added on the case 102 or the frame 204 . The screw 104 is screwed in the screw hole 203 of frame outer walls 2044 from the outside of the LCD housing space of the frame 2042 . [0074] FIG. 9 illustrates a sectional view of a section near the screw hole 203 and the screw 104 . The screw head 1041 of the screw 104 is buried into the gap between the frame outer wall 2044 and the frame inner wall 2045 , so the screw head 1041 does not protrude from the frame outer wall 2043 . A tip of the screw 104 contacts the side rubber press section 1032 . The tip of the screw 104 screwed in the screw hole 203 presses and deforms the side rubber 103 . As the result, bounce is produced between the case 102 and the LCD side faces 1013 , and all the side rubber contact sections 1031 contact LCD side faces 1013 . The display section 100 in this exemplary embodiment has such a structure to use the bounce for supporting the LCD unit 101 accordingly, the LCD unit 101 can be protected from the impulse force or shock transmitted from the case 102 . In addition, screw holes 203 are not formed on the case 102 but on the frame 204 separate from the case 102 . As such, the case 102 can be made safe in a screwing process of the screw 104 and the screw hole 203 , because the screwing process can be done far from the case 102 that is often expensive. Moreover, if the screw hole 203 is broken, it is needless to change the case 102 . Third Exemplary Embodiment [0075] FIG. 10 illustrates a sectional view of the display section 100 in a plane parallel to a display face 1011 of a LCD unit 101 in this exemplary embodiment. [0076] In this exemplary embodiment, screw holes 203 are formed on two faces of inside side faces of the case 1023 . One of the faces that the screw hole 203 is formed on is a face facing the LCD top face, and another is a face facing the LCD left side face 1017 . The LCD left side face 1017 faces to the screw 104 but the LCD right side face 1015 does not face to the screw 104 . The LCD top face 1014 faces the screw 104 but the LCD bottom face 1016 does not face the screw 104 . That is, a certain face faces to the screw 104 , a face behind the face does not face any screw 204 . The screw 104 is screwed in the screw hole 203 of the case 102 from the outside of the case 102 . [0077] A tip of the screw 104 contacts the side rubber press section 1032 . The tip of the screw 104 screwed in the screw hole 203 presses and deforms the side rubber 103 . As the result, bounce is produced between the case 102 and the LCD left side face 1017 , and all the side rubber contact sections 1031 contact LCD left side face 1017 . The LCD unit 101 which is pushed from the left side presses the side rubber 103 at the other right side. As a result, bounce is produced between the case 102 and the LCD right side face 1015 . Also, and all the side rubber contact sections 1031 contact LCD right side face 1015 . [0078] FIG. 11 illustrates a sectional view of the display section 100 in a plane parallel to the LCD left side face 1017 of the LCD unit 101 . In this exemplary embodiment, the inside front face of the case 1025 does not have a screw hole 203 . The screw hole 203 of the inside back face of the case 1028 is substantially perpendicular to the LCD back face 1018 in depth. A plurality of screw holes 203 are formed in line parallel to four sides of the inside back face of the case 1028 . The LCD back face 1018 faces the screw 104 but the display face 1011 does not face the screw 104 . That is, a certain face faces the screw 104 and a face behind the face does not face any screw 204 . A tip of the screw 104 contacts the back rubber press section 1082 . The tip of the screw 104 screwed in the screw hole 203 presses and deforms the back rubber 108 . As a result, shock is absorbed and bounce is produced between the case 102 and the LCD back face 1018 , and all the back rubber contact sections 1081 contact LCD back face 1018 . The LCD unit 101 which is pushed from the back presses the front rubber 105 in the other front. As a result, bounce is produced between the case 102 and the display face 1011 also, and all the front rubber contact sections 1051 contact display face 1011 . In this exemplary embodiment, a certain face faces the screw 104 but a face behind the face does not face any screw 204 . Accordingly, a relative position of the LCD unit 101 to the case 102 is easily set up. Moreover, structure of the display section 100 can be made simpler. Fourth Exemplary Embodiment [0079] FIG. 12 illustrates a sectional view of the display section 100 in a plane parallel to a display face 1011 of a LCD unit 101 in this exemplary embodiment. In this exemplary embodiment, the side rubber 103 is formed like a bar or a belt. The side rubber 103 is folded in the gap between the LCD unit 101 and inside side faces of the case 1023 . Such a bar (or a belt) stile rubber can be produced easily. [0080] The side rubber 103 has a crena or notch at the folded point corresponding to the corner of the LCD unit 101 . The side rubber 103 has a length to contact to every LCD side faces 1013 . Both ends of the side rubber 103 are located in a gap between the LCD bottom face 1016 and the inside side faces of the case 1023 . Wire harnesses can be placed in a void between both ends of the side rubber 103 . This void can be used as a roll off for the deformation of the side rubber 103 . [0081] Such a bar (or a belt) stile rubber can be used not only as above, but also as a rubber that contacts the display face 1011 , the LCD top face 1014 , the LCD back face 1018 , and the LCD bottom face 1016 , and as a rubber that contacts the display face 1011 , the LCD left side face 1017 , the LCD back face 1018 , and the LCD right side face 1015 . Each rubber has a length to all every four faces that the rubber contacts respectively. Fifth Exemplary Embodiment [0082] FIG. 13 illustrates a sectional view of the display section 100 in the plane parallel to the display face 1011 of the LCD unit 101 in this exemplary embodiment. In this exemplary embodiment, the side rubber 103 is formed as four bars. Four side rubbers 103 are folded in each gap between edges of the LCD unit 101 and inside side faces of the case 1023 , respectively. Such short bar stile rubbers can be produced easily. [0083] Four side rubbers 103 are respectively pushed by screws 104 respectively screwed in screw holes 203 of each of inside side faces of the case 1023 . According to this exemplary embodiment, it is easy to form side rubbers 103 . Sixth Exemplary Embodiment [0084] FIG. 14 illustrates a sectional view of the display section 100 in a plane parallel to the display face 1011 of the LCD unit 101 in this exemplary embodiment. In this exemplary embodiment, a total of sixteen side rubbers are used. Four side rubbers 103 are inserted in each four gaps between LCD side faces 1013 and inside side faces of the case 1023 . [0085] The screw hole 203 is formed on each of the inside side faces of the case 1023 . Each of screw holes 203 are respectively perpendicular to the LCD side faces 1013 in depth. Side rubbers 103 respectively have a side rubber contact section 1031 that contacts one of the LCD side faces 1013 . Side rubbers 103 also respectively have a side rubber press section 1032 which contacts the screw 104 , behind the side rubber contact section 1031 . [0086] The screw hole 203 faces the side rubber press section 1032 . A thrust of the screw 104 transmits to the side rubber contact section 1031 . The screw 104 is screwed in the screw hole 203 of the case 102 from the outside of the case 102 . A tip of the screw 104 contacts the side rubber press section 1032 . [0087] FIG. 15 illustrates a sectional view of the display section 100 in a plane parallel to the display back face 1018 of the LCD unit 101 . FIG. 16 illustrates a sectional view of the display section 100 in a plane parallel to the LCD left side face 1017 of the LCD unit 101 , in this exemplary embodiment. In this exemplary embodiment, sixteen back rubbers 108 are folded in the gap between the LCD back face 1018 and the inside back face of the case 1028 . Four back rubbers 108 are folded around each edge of the LCD back face 1018 . [0088] Screw holes 203 are opened on the inside back face of the case 1028 . Four screw holes 203 are opened along each edge of the inside back face of the case 1028 . Screws 104 are respectively screwed in the screw hole 203 of the case 102 from the outside of the case 102 . A tip of the screw 104 contacts the side rubber press section 1032 . According to this exemplary embodiment, a plurality of rubbers are folded in the gap between a certain face of the LCD unit 101 and an inside face of the case 102 facing to the certain face of the LCD unit 101 , so it is easy to form rubbers. Seventh Exemplary Embodiment [0089] FIG. 17 illustrates a perspective view of angle rubbers 109 in this exemplary embodiment. The angle rubbers 109 are formed like an integration of one of side rubbers 103 and one of back rubbers 108 in the sixth exemplary embodiment. Between the LCD unit 101 and the case 102 , angle rubbers 109 are folded instead of the side rubber 103 and the back rubber 108 . Angle rubbers 109 are respectively pressed by screws 104 respectively screwed in the screw holes 203 opened on the inside side faces of the case 1023 and inside back face of the case 1028 . According to this exemplary embodiment, the number of parts is reduced, and assembly of the display section can be easily performed. In addition, it is possible to form the angle rubber as an integration of one of front rubbers 105 and one of side rubbers 103 . Eighth Exemplary Embodiment [0090] FIG. 19 illustrates a perspective view of the LCD unit 101 and a cushion rubber 110 in this exemplary embodiment. The cushion rubber 110 is formed as a horseshoe shape covering an edge of the display face 1011 , the LCD back face 1018 , and an edge of the LCD back face 1018 . The cushion rubber 110 is placed between the LCD unit 101 and the case 102 instead of the front rubber 105 , side rubber 103 , and the back rubber 108 . [0091] Tips of the screws 104 screwed in screw holes 203 opened on each face of the LCD housing space 202 press and deform the cushion rubber 110 . As the result, bounce is produced between the case 102 and the LCD unit 101 , and cushion rubber 110 contacts the LCD unit 101 . According to this exemplary embodiment, the number of parts is reduced, and assembly of the display section can be easily performed. Ninth Exemplary Embodiment [0092] FIG. 20 illustrates a sectional view of the display section 100 in a plane parallel to a display face 1011 of a LCD unit 101 in this exemplary embodiment. In this exemplary embodiment, a pad 111 is placed between the side rubber 103 and the tip of the screw 104 . The pad 111 may be made from such metal as stainless steel, aluminum, or any material that can support the pressing force of the screw 104 . [0093] FIG. 21 illustrates a sectional view of a section near the screw hole 203 and the screw 104 . A tip of the screw 104 contacts the pad 111 , and the pad 111 contacts the side rubber 103 . The tip of the screw 104 screwed in the screw hole 203 pushes the pad 111 , and the pad 111 presses and deforms the side rubber 103 . As the result, bounce is produced between the case 102 and the LCD side faces 1013 , and all the side rubber contact sections 1031 contact LCD side faces 1013 . The pad 111 scatters the pressing power from the screw 104 , and transmits the scattered power to the side rubber 103 . As the result, the pressing power from the screw 104 does not concentrate on the side rubber 103 , and the side rubber 103 is prevented from damage. In addition, it is possible to prepare the pad 111 not only for the side rubber 103 , but also for the other rubbers such as the front rubber 105 and the back rubber 108 . Tenth Exemplary Embodiment [0094] FIG. 22 illustrates a sectional view of the display section 100 in the plane parallel to the display face 1011 of the LCD unit 101 in this exemplary embodiment. A pad 112 is placed in the gap between the side rubber press section 1032 and the inside side faces of the case 1023 . The pad 112 has a length almost equal to one of the LCD side faces that the pad is facing. [0095] FIG. 23 illustrates a sectional view of a section near the screw hole 203 and the screw 104 . A tip of the screw 104 contacts the pad 112 . The pad 112 contacts the side rubber press section 1032 . The tip of the screw 104 screwed in the screw hole 203 pushes the pad 112 , and the pad 112 presses widely and deforms the side rubber 103 . As the result, bounce is produced between the case 102 and the LCD side faces 1013 , and all the side rubber contact sections 1031 contact LCD side faces 1013 . The pad 112 scatters the pressing power from the screw 104 , and transmits the scattered power to the side rubber 103 . As the result, the pressing power from the screw 104 does not concentrate on the side rubber 103 , and thus, the side rubber 103 is prevented from damage. In addition, it is possible to prepare the pad 112 not only for the side rubber 103 , but also for the other rubbers such as the front rubber 105 and the back rubber 108 . Eleventh Exemplary Embodiment [0096] FIG. 24 illustrates a sectional view of the display section 100 in the plane parallel to the LCD side face 1013 of the LCD unit 101 before pressing the side rubber 103 in this exemplary embodiment. The pad 113 that receives the tip of the screw 104 is formed longer than the LCD side face 1013 in the direction perpendicular to the display face 1011 . In the direction perpendicular to the display face 1011 , both ends of the pad 113 jut from the plane that contacts the side rubber 103 . The side rubber 103 is formed like a belt, and side rubber contact section 1031 that is the longer side of the cross section of the side rubber 103 will contact the LCD side face 1013 . [0097] FIG. 25 illustrates a sectional view of the display section 100 in the plane parallel to the LCD side face 1013 of the LCD unit 101 when the pad 113 is pressing the side rubber 103 in this exemplary embodiment. The pad 113 having the jut portion presses and deforms the side rubber 103 along the LCD side face 1013 and the pad 113 . The side rubber 103 deforms and clips the edge of the LCD unit 101 . As a result, the side rubber 103 can support the LCD unit 101 in the direction perpendicular to the display face 1011 or the LCD back face 1018 . Therefore, the number of parts is reduced, and assembly of the display section can be easily performed. Twelfth Exemplary Embodiment [0098] FIG. 26 illustrates a sectional view of the display section 100 in the plane parallel to the display face 1011 of the LCD unit 101 in this exemplary embodiment. In this exemplary embodiment, the display section 100 includes the leaf spring 300 as a press member instead of the screw 104 . [0099] The LCD housing space 202 of the display section 100 has plurality of a leaf spring attachments 302 on the inside side face of the case 1023 . The leaf spring 300 has enough elastic force to fit the side rubber contact section 1031 of the side rubber 103 to the LCD unit 101 . The leaf spring 300 is pressed into the leaf spring attachment 302 . The leaf spring 300 has a protruding portion that protrudes from the leaf spring attachment 302 . The protruding portion contacts the side rubber press section 1032 and presses the side rubber 103 . [0100] A plurality of leaf spring attachments 302 have openings on a side facing the side rubber 103 and the side facing the inside front face of the case 1025 . [0101] FIG. 27 illustrates a exploded view of the display section 100 in this exemplary embodiment. The case 102 is separately formed as a main body 1027 and a lid 1029 . The main body 1027 covers LCD side faces 1013 and LCD back face 1018 . The lid 1029 has an opening at a position facing to the displaying area 1012 . [0102] Leaf spring attachments 302 are formed in each side of the inside side face of the case 1023 . Leaf springs 300 are inserted in each of leaf spring attachments 302 . The inside back face of the case 1028 also has a plurality of the leaf spring attachments 302 for storing the leaf spring 300 . [0103] The back rubber 108 is put on the leaf spring 300 pressed into the leaf spring attachment 302 of the inside back face of the case 1028 . The LCD unit 101 is put on the back rubber 108 . The side rubber is inserted into the gap between the LCD unit 101 and the case 102 . After that, the leaf spring 300 is pressed into the leaf spring attachment 302 of the inside side face of the case 1023 . After pressing the leaf spring 300 into the leaf spring attachment 302 of the inside side face of the case 1023 , the front rubber 105 is put on the LCD unit 101 . The lid 1029 is put on the front rubber 105 , and fixed on the main body 1027 . [0104] According to this exemplary embodiment, the spring is used instead of the screw, so it is possible to dispense with the screwing, allowing the display section to be easily assembled. In addition, the leaf spring 300 can be replaced with any elastic body that has enough elasticity and bounce. [0105] It is described that the screw hole 203 is opened on the case 102 or the frame 204 directly. It is also possible to form the screw hole 203 on another independent member (screw hole member) as shown in FIG. 28 . The screw hole member may have a collar. The collar spreads the pressure transmitted the case 102 or the frame 204 . [0106] In addition, although the above exemplary embodiments are described about a notebook PC, this invention can be also used in a cellular phone, a clock, a personal digital assistant, or any equipment comprising a display panel such as an LCD. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
A display apparatus including: a display unit configured to display an image; a shock absorbing elastic body configured to contact the display unit; a press member configured to press against the elastic body; and a catch member configured to secure the press member; wherein the elastic body absorbs shock transferred from the catch member to the press member.
6
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a national phase filing under USC §371 from PCT Application Serial No. PCT/US2011/030868, filed Apr. 1, 2011, which claims the benefit of U.S. Provisional Application Ser. No. 61/320,129, filed Apr. 1, 2010, both of which applications are hereby incorporated by reference in their entirety. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] This invention was made with government support under K08-CA09517 awarded by the National Institutes of Health (NIH). The government has certain rights in the invention. TECHNICAL FIELD [0003] The present disclosure relates generally to imaging agents and, in particular, imaging agents used to image and/or detect neuroblastoma. More specifically, the present disclosure concerns the imaging of neuroblastoma using a nonradioactive near infrared dye labeled benzylguanidine analog. BACKGROUND OF THE INVENTION [0004] Neuroblastoma is the most common extra-cranial solid cancer in pediatric patients. Despite chemotherapy, surgery and radiation therapy, neuroblastoma's aggressive malignancy accounts for more than 15% of all pediatric cancer deaths (Lonergan et al., 2002 and Maris et al., 2007). Metastatic spread is the most important risk factor in predicting survival. Other risk factors are the age of the child at diagnosis and the biologic features of the tumor. Survival for localized tumors nears 95% with surgical resection alone. However, treatment for metastatic or biologically aggressive tumors (high risk neuroblastoma) requires an intense multi-modality approach including surgical resection, chemotherapy, radiotherapy, and high dose chemotherapy with autologous stem cell rescue. Despite initial responses in the majority of patients with high risk neuroblastoma, the tumor commonly recurs. Effectively, treating patients with neuroblastomas remains a challenging task for both clinicians and researchers. [0005] Neuroblastoma's arise from neural crest precursors that express components of the mature catecholamine metabolic pathway. This catecholamine-secreting tumor is derived from neural crest cells, which are precursors of the sympathetic nervous system (Rha et al., 2003). Ninety to 95% of tumors actively take up norepinephrine precursors via the specific norepinephrine transporter and non-specific pathways. MIBG (meta-iodobenzylguanidine) is a norepinephrine analog that utilizes these transporter pathways. While MIBG has been used clinically for over 2 decades, the exact mechanism of MIBG accumulation in human neuroblastoma cells and tumors is not well defined (Koopmans et al., 2009). MIBG and other norepinephrine analogues are taken up by neuroendocrine derived tumors such as neuroblastoma and pheochromocytoma through multiple mechanisms including active transport by amine precursor receptors such as the NET (Norepinehrine receptor) and non-specific metabolic uptake. Although MIBG negative tumors have been found to be NET negative, the correlation between level of NET expression and MIBG uptake remains poorly defined for neuroblastoma. There is evidence that the vesicular monoamine transporters (VMAT1 and VMAT2), which are highly expressed in neuroblastoma, act to sequester MIBG in cytoplasmic granules (Kolby et al., 2003). [0006] Neuroblastoma tumors can develop anywhere in the sympathetic nervous system with variable signs and symptoms in young children (Papaioannou and McHugh, 2005). Therefore, a complete understanding of specific characteristics of the disease, including tumor location, size, stage, early detection of relapse and treatment response, is critical for designing effective treatment regimens. Molecular imaging technology plays an important role in this process, because imaging may be used as a tool to interrogate cellular and molecular biological events. [0007] The most commonly used neuroblastoma imaging agent is meta-iodobenzylguanidine (MIBG), labeled with an iodine radioisotope, I 123 or I 131 . Radiolabeling MIBG with I 123 emits low energy (159 Kev) gamma radiation which is ideal for single photon emission computed tomography (SPECT) detection and makes MIBG radiolabeled with I 123 useful for diagnosis and management of neuroblastoma. MIBG radiolabeled with I 123 has been used in clinical practice since the 1980s (Valk et al., 1981; Wieland et al., 1980), and has been a mainstay in imaging neuroblastomas for decades in the pediatric population (Howman-Giles et al., 2007; Rufini et al., 2006; Vik et al., 2009). [0008] However, long-term safety concerns associated with the use of radiolabeled meta-iodobenzylguanidine are valid, especially when it is used repeatedly in young patients, as radiation exposure increases the risk of developing secondary cancers and increased therapy-related toxicity (Howman-Giles et al., 2007). Another health concerns is that by exposing the patient to radioactive iodine adds to the logistical complications by posing a risk to the thyroid which is abrogated by the use of concomitant oral iodine. [0009] Radioactive compounds are limited for longitudinal and cell studies due to their relatively short half-life (Sisson and Shulkin, 1999; Wafelman et al., 1994). The very short T 1/2 of I 123 is about 12.5 hours. This relatively short half-life requires that the agent is used within a day of synthesis for maximum sensitivity and limits qualitative comparison between scans in the same patient performed at different times. [0010] Another limitation is that radioactive compounds are limited by their low resolution (Wong and Kim, 2009). The spatial resolution of SPECT images derived from radiolabeled MIBG is poor thereby adding little anatomic information. False negatives from extensive necrotic tumors, drug interference (e.g. labetalol) or technical problems are common as well as false positives from thymus and brown fat. Cardiac uptake, liver uptake or uptake in nonspecific and non-uniform bowel may contribute to reducing the sensitivity and specificity MIBG scans. As such, the disadvantages of radioactive agents restrict their use in both pre-clinical and clinical investigations. [0011] Optical imaging is an active and promising area for both in vitro and in vivo molecular imaging studies. Of the various optical imaging techniques used to date, near infrared (NIR) fluorescence imaging is particularly promising. The wavelength for near infrared light ranges from 700 to 900 nanometers with minimal autofluorescence, and is minimally absorbed by hemoglobin (the principal absorber of visible light), water, and lipids (the principal absorbers of infrared light). Considering the advantages of NIR imaging, this method could provide an attractive approach for improving the imaging accuracy and safety for pediatric patients. [0012] The object of this disclosure is to provide nonradioactive NIR optical imaging agents based upon the structure of MIBG. The nonradioactive NIR optical imaging agent, W765-BG, has been evaluated at the cellular level by confocal microscopy, and in vivo in a whole animal using a human neuroblastoma xenograft model. The specific uptake of this agent in both neuroblastoma cells and tumors demonstrate that W765-BG is useful for neuroblastoma studies and diagnoses. BRIEF SUMMARY OF THE INVENTION [0013] The present invention is directed to a composition and method for non-radioactive, near-infrared imaging. Specifically, the compositions and methods disclosed herein allow for imaging of neuroblastomas without the use of radio-labeled imaging agents. [0014] Accordingly, the present disclosure provides a composition having a meta-functionalized benzyl guanidine, a spacer moiety, a linker moiety and non-radioactive dye. The spacer moiety has a reactive amino functionality. The spacer moiety is chemically bonded to the meta-functionalized benzyl guanidine, the linker moiety is chemically bonded to the spacer moiety and the dye is chemically bonded to the linker moiety. The chemical bond connecting the meta-functionalized benzyl guanidine and the spacer moiety is an ester, ether, thioether, thioester, amide, a carbon-carbon single bond, a carbon-carbon double bond, or a carbon-carbon triple bond. [0015] The spacer moiety is a functionalized alkyl (C=1-8) , alkenyl (C=1-8) , or aralkyl (C=1-8) , or a substituted version of any of these moieties. The linker moiety is a functionalized alkyl (C=1-8) , alkenyl (C=1-8) , or aralkyl (C=1-8) , or a substituted version of any of these moieties. In some examples, the dye is a contrast agent. In specific examples, the dye is IRdye800CW, IRdye800RS, or IRdye700DX. [0016] In additional and alternate embodiments, the present disclosure provides composition having the general formula: [0000] [0017] wherein X is O, CH 2 , CH, C, NH, S or C═O; R 1 has the general formula [0000] R 3 -R 4 -R 5 [0018] wherein R 3 is chemically bonded to X to form an amide, thioester, ester, ether, carbon-carbon bond, carbon-carbon double bond, or a carbon-carbon triple bond, R 4 is alkyl (C=1-8) , alkenyl (C=1-8) , or aralkyl (C=1-8) , or a substituted version of any of these groups, R 5 is chemically bonded to R 2 to from an amide, thioester, ester, ether, carbon-carbon bond, carbon-carbon double bond, or a carbon-carbon triple bond, R 2 is alkyl (C=1-8) , alkenyl (C=1-8) , or aralkyl (C=1-8) , or a substituted version of any of these groups and forms an amino bond with the dye, and the dye is a fluorophore. [0019] In specific embodiments, X is NH. In other embodiments, R 3 forms an amide bond. In certain embodiments, R 4 is alkyl (C=1-2) . In some embodiments, R 5 and the R 2 are chemically joined by an amide bond. In specific examples, the composition has the formula: [0000] [0020] Additionally, the present disclosure provides a method for imaging neuroblastomas comprising the step of treating a subject with a compound having the general formula: [0000] [0021] wherein X is O, CH 2 , CH, C, NH, S or C═O; R 1 has the general formula [0000] R 3 -R 4 -R 5 [0022] wherein R 3 is chemically bonded to X to form an amide, thioester, ester, ether, carbon-carbon bond, carbon-carbon double bond, or a carbon-carbon triple bond, R 4 is alkyl (C=1-8) , alkenyl (C=1-8) , or aralkyl (C=1-8) , or a substituted version of any of these groups, R 5 is chemically bonded to R 2 to from an amide, thioester, ester, ether, carbon-carbon bond, carbon-carbon double bond, or a carbon-carbon triple bond, R 2 is alkyl (C=1-8) , alkenyl (C=1-8) , or aralkyl (C=1-8) , or a substituted version of any of these groups and forms an amino bond with the dye, and the dye is a fluorophore. [0023] In some embodiments, the particular composition used to image neuroblastomas has the formula: [0000] [0024] The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS [0025] For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which: [0026] FIG. 1 shows the imaging of W765-BG in neuroblastoma cells. Cells treated with W765-BG (top panel) or free dye (bottom panel), and were visualized by confocal microscopy (a) is the cell nuclei, (b) shows the cell with the dye, W765-BG (top panel) and free dye (bottom panel), and (c) shows the merged image of (a) and (b). [0027] FIG. 2 shows the imaging of W765-BG in human tumor xenografts in mice. Mice were injected with NGP.Luc cells, followed by injections with Luciferin and W765-BG. Whole animal images were collected over the course of eight days, and the 48 hour time point is shown in FIG. 2 where FIG. 2A is the white light image, FIG. 2B is the X-ray image, FIG. 2C is the NIR image, FIG. 2D is the luciferase image, FIG. 2E is the merged image of FIG. 2C and FIG. 2D , and FIG. 2F is the merged image of FIG. 2C , FIG. 2D , and FIG. 2E . [0028] FIG. 3 shows the confocal images of W765-BG uptake in human neuroblastoma cells. FIG. 3A shows bright field images of cell morphology and location. FIG. 3B shows the cell nuclei from a signal cell stack at a thickness of 0.5 micrometers. FIG. 3C shows the W765-BG signal from the image of FIG. 3B . FIG. 3D shows the merged images of FIGS. 3A-C . The results show that the cells maintain their morphology after incubation with W765-BG overnight. The cell nuclei signals are from inside the cell membrane. W765-BG binds to all cells and incorporates into the cell nuclei (yellow). FIG. 3E shows a high magnification overlaid view of W765-BG uptake by a neuroblastoma cell. FIG. 3F shows a high magnification merged image of cell morphology and free dye uptake. FIG. 3G shows that W765-BG signal intensity comes from the cell. FIG. 3H shows the free dye signal intensity. FIG. 3 shows that the neuroblastoma cells take up the W765-BG agent, but not the free dye. [0029] FIG. 4 shows in vivo images of neuroblastoma xenografts. FIG. 4A shows the luciferase image of NB1691.Luc xenograft. The tumor node is localized with clear tumor margins at this stage. FIG. 4B shows a vasculature image of NBG169.Luc tumor xenograft. A black hole is found in the region indicated by the arrow. The tumor-to-background ratio of this region is 0.79. FIG. 4C shows the W765-BG image of the same animal. A signal decrease region is indicated by the arrow. The tumor-to-background ratio of this region is 0.95. FIG. 4D shows a merged luciferase, vasculature and W765-BG image. The luciferase positive tumor nodal fits perfectly into the black hole of the vasculature and signal decrease region of W765-BG images. FIG. 4E shows merged X-ray and W765-BG images with anatomical location of whole body W765-BG signal distribution. FIG. 4F shows merged multi-energy images indicating the relationship between tumor node, vasculature, W765-BG, and anatomy. FIG. 4G shows a luciferase image of NGP.luc xenograft. The tumor growth pattern is diffused and without a clear margin compared to the NB1691.Luc tumor. FIG. 4H shows a vasculature image with an increased tumor to background ratio of 1.13 (TBR=1.13). FIG. 4I shows a WW765-BG signal slightly increased at this stage (TBR=1.08). FIG. 4J shows merged images of the NGP.Luc tumor having a different growth pattern in comparison with NB1691.Luc, as well as a different distribution of vasculature and W765-BG agents. FIG. 4K shows the W765-BG whole body distribution. FIG. 4L shows the merged NGP.Luc images. FIG. 4M shows a tumor node. FIG. 4N shows a vasculature image with the imaging agent having a high signal surrounding the tumor region. The tumor to background ratio reached 1.9. FIG. 4O shows that the W765-BG agent was taken up by the tumor and the tumor to background ratio reached 2.8. FIG. 4P shows optical images of the tumor node, vasculature agent, and W765-BG agent signals were overlaid. The distribution of W765-BG was different than the vasculature agent. W765-BG agent was mainly in the tumor region, while the vasculature agent was in the tumor and kidney regions. FIG. 4Q shows that W765-BG was concentrated in the tumor region at this stage. FIG. 4R shows merged multi-energy images which illustrates the relationship between the anatomy, the disease, and the imaging agents. [0030] FIG. 5 shows the late stage disease, organ, and pathological image. FIG. 5A shows a color image of tumor bearing animal. FIG. 5B shows that a majority of the vasculature agent was located in the kidneys at this disease stage. FIG. 5C shows that W765-BG is located only in the tumor region. FIG. 5D shows a luciferase image with uneven signal distribution in the tumor region. FIG. 5E shows a color image of the organ layout. FIG. 5F shows a merged X-ray and vasculature image that confirms the whole body result that this agent was located in the kidneys. FIG. 5G shows that the W765-BG signal was from the liver, spleen and tumor. FIG. 5H shows a merged organ image with the imaging agents distributed into different organs. Pathology confirmed that the organs with imaging agents were the tumor ( FIG. 5I ), muscle ( FIG. 5J ), liver ( FIG. 5K ), kidney ( FIG. 5L ), and spleen ( FIG. 5M ). [0031] FIG. 6 shows the statistical comparison of injection time ( FIG. 6A ) and cell line ( FIG. 6B ) differences. FIG. 6A shows the tumor to background ratio differences at different imaging time points. FIG. 6B shows the uptake differences between the cell lines and the W765-BG imaging agent. DETAILED DESCRIPTION OF THE INVENTION [0032] It will be readily apparent to one skilled in the art that various embodiments and modifications may be made in the invention disclosed herein without departing from the scope and spirit of the invention. I. DEFINITIONS [0033] In any embodiment herein, any R group (R 1 , R 2 , R 3 , R 4 , and/or R 5 ) may be further defined as alkyl (C=1-8) , such as methyl, ethyl, n-propyl, or isopropyl. Any R group may comprise an alkenyl (C=1-8) group, such as allyl. Any R group may comprise a substituted or unsubstituted aralkyl (C=1-8) group, such as benzyl or 2-furanylmethyl. [0034] In any embodiment herein regarding alkyl (C=1-8) , aryl (C=1-8) and aralkyl (C=1-8) groups (e.g., alkyl (C=1-8) , alkyl (C=1-8) sulfonate, alkyl (C=1-8) halide, aryl (C=1-8) sulfonate, aralkyl (C=1-8) , etc.), it is specifically contemplated that the number of carbons may be 1, 2, 3, 4, 5, 6, 7, or 8, or any range derivable therein. It is also specifically contemplated that any particular number of carbon atoms may be excluded from any of these definitions. [0035] As used herein, “halide” means independently —F, —Cl, —Br or —I and “sulfonyl” means —SO 2 —. [0036] The term “alkyl,” when used without the “substituted” modifier, refers to a non-aromatic monovalent group, having a saturated carbon atom as the point of attachment, a linear or branched, cyclo, cyclic or acyclic structure, no carbon-carbon double or triple bonds, and no atoms other than carbon and hydrogen. The groups, —CH 3 (Me), —CH 2 CH 3 (Et), —CH 2 CH 2 CH 3 (n-Pr), —CH(CH 3 ) 2 (iso-Pr), —CH(CH 2 ) 2 (cyclopropyl), —CH 2 CH 2 CH 2 CH 3 (n-Bu), —CH(CH 3 )CH 2 CH 3 (sec-butyl), —CH 2 CH(CH 3 ) 2 (iso-butyl), —C(CH 3 ) 3 (tert-butyl), —CH 2 C(CH 3 ) 3 (neo-pentyl), cyclobutyl, cyclopentyl, cyclohexyl, and cyclohexylmethyl are non-limiting examples of alkyl groups. The term “substituted alkyl” refers to a non-aromatic monovalent group, having a saturated carbon atom as the point of attachment, a linear or branched, cyclo, cyclic or acyclic structure, no carbon-carbon double or triple bonds, and at least one atom independently selected from the group consisting of N, O, F, Cl, Br, I, Si, P, and S. The following groups are non-limiting examples of substituted alkyl groups: —CH 2 OH, —CH 2 Cl, —CH 2 Br, —CH 2 SH, —CF 3 , —CH 2 CN, —CH 2 C(O)H, —CH 2 C(O)OH, —CH 2 C(O)OCH 3 , —CH 2 C(O)NH 2 , —CH 2 C(O)NHCH 3 , —CH 2 C(O)CH 3 , —CH 2 OCH 3 , —CH 2 OCH 2 CF 3 , —CH 2 OC(O)CH 3 , —CH 2 NH 2 , —CH 2 NHCH 3 , —CH 2 N(CH 3 ) 2 , —CH 2 CH 2 Cl, —CH 2 CH 2 OH, —CH 2 CF 3 , —CH 2 CH 2 OC(O)CH 3 , —CH 2 CH 2 NHCO 2 C(CH 3 ) 3 , and —CH 2 Si(CH 3 ) 3 . In certain embodiments, “lower alkyl” groups are contemplated, wherein the total number of carbon atoms in the lower alkyl group is 6 or less. [0037] The term “alkenyl” when used without the “substituted” modifier refers to a monovalent group, having a nonaromatic carbon atom as the point of attachment, a linear or branched, cyclo, cyclic or acyclic structure, at least one nonaromatic carbon-carbon double bond, no carbon-carbon triple bonds, and no atoms other than carbon and hydrogen. Non-limiting examples of alkenyl groups include: —CH═CH 2 (vinyl), —CH═CHCH 3 , —CH═CHCH 2 CH 3 , —CH 2 CH═CH 2 (allyl), —CH 2 CH═CHCH 3 , and —CH═CH—C 6 H 5 . The term “substituted alkenyl” refers to a monovalent group, having a nonaromatic carbon atom as the point of attachment, at least one nonaromatic carbon-carbon double bond, no carbon-carbon triple bonds, a linear or branched, cyclo, cyclic or acyclic structure, and at least one atom independently selected from the group consisting of N, O, F, Cl, Br, I, Si, P, and S. The groups, —CH═CHF, —CH═CHCl and —CH═CHBr, are non-limiting examples of substituted alkenyl groups. [0038] The term “aryl,” when used without the “substituted” modifier, refers to a monovalent group, having an aromatic carbon atom as the point of attachment, said carbon atom forming part of a six-membered aromatic ring structure wherein the ring atoms are all carbon, and wherein the monovalent group consists of no atoms other than carbon and hydrogen. Non-limiting examples of aryl groups include phenyl (Ph), methylphenyl, (dimethyl)phenyl, —C 6 H 4 CH 2 CH 3 (ethylphenyl), —C 6 H 4 CH 2 CH 2 CH 3 (propylphenyl), —C 6 H 4 CH(CH 3 ) 2 , —C 6 H 4 CH(CH 2 ) 2 , —C 6 H 3 (CH 3 )CH 2 CH 3 (methylethylphenyl), —C 6 H 4 CH═CH 2 (vinylphenyl), —C 6 H 4 CH═CHCH 3 , —C 6 H 4 C≡CH, —C 6 H 4 C≡CCH 3 , naphthyl, and the monovalent group derived from biphenyl. The term “substituted aryl” refers to a monovalent group, having an aromatic carbon atom as the point of attachment, said carbon atom forming part of a six-membered aromatic ring structure wherein the ring atoms are all carbon, and wherein the monovalent group further has at least one atom independently selected from the group consisting of N, O, F, Cl, Br, I, Si, P, and S. Non-limiting examples of substituted aryl groups include the groups: —C 6 H 4 F, —C 6 H 4 Cl, —C 6 H 4 Br, —C 6 H 4 I, —C 6 H 4 OH, —C 6 H 4 OCH 3 , —C 6 H 4 OCH 2 CH 3 , —C 6 H 4 OC(O)CH 3 , —C 6 H 4 NH 2 , —C 6 H 4 NHCH 3 , —C 6 H 4 N(CH 3 ) 2 , —C 6 H 4 CH 2 OH, —C 6 H 4 CH 2 OC(O)CH 3 , —C 6 H 4 CH 2 NH 2 , —C 6 H 4 CF 3 , —C 6 H 4 CN, —C 6 H 4 CHO, —C 6 H 4 C(O)CH 3 , —C 6 H 4 C(O)C 6 H 5 , —C 6 H 4 CO 2 H, —C 6 H 4 CO 2 CH 3 , —C 6 H 4 CONH 2 , —C 6 H 4 CONHCH 3 , and —C 6 H 4 CON(CH 3 ) 2 . [0039] The term “aralkyl” when used without the “substituted” modifier refers to the monovalent group -alkanediyl-aryl, in which the terms alkanediyl and aryl are each used in a manner consistent with the definitions provided herein. Non-limiting examples of aralkyls are: phenylmethyl (benzyl, Bn), 1-phenyl-ethyl, 2-phenyl-ethyl, indenyl and 2,3-dihydro-indenyl, provided that indenyl and 2,3-dihydro-indenyl are only examples of aralkyl in so far as the point of attachment in each case is one of the saturated carbon atoms. When the term “aralkyl” is used with the “substituted” modifier, either one or both the alkanediyl and the aryl is substituted. Non-limiting examples of substituted aralkyls are (3-chlorophenyl)-methyl, 2-oxo-2-phenyl-ethyl (phenyl-carbonylmethyl), 2-chloro-2-phenyl-ethyl and 2-methylfuranyl. [0040] The term “alkynediyl” when used without the “substituted” modifier refers to a non-aromatic divalent group, wherein the alkynediyl group is attached with two σ-bonds, with two carbon atoms as points of attachment, a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon triple bond, and no atoms other than carbon and hydrogen. The groups, —C≡C—, —C≡CCH 2 —, and —C≡CCH(CH 3 )— are non-limiting examples of alkynediyl groups. The term “substituted alkynediyl” refers to a non-aromatic divalent group, wherein the alkynediyl group is attached with two σ-bonds, with two carbon atoms as points of attachment, a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon triple bond, and at least one atom independently selected from the group consisting of N, O, F, Cl, Br, I, Si, P, and S. The groups —C≡CCH(F)— and —C≡CCH(Cl)— are non-limiting examples of substituted alkynediyl groups. [0041] The terms “alkyl sulfonate” and “aryl sulfonate” refer to compounds having the structure —OSO 2 R, wherein R is alkyl or aryl, as defined above, including substituted versions thereof. Non-limiting examples of alkyl sulfonates and aryl sulfonates include mesylate, triflate, tosylate and besylate. In certain embodiments, mesylates are excluded from compounds of the present invention. [0042] As used herein, “protecting group” refers to a moiety attached to a functional group to prevent an otherwise unwanted reaction of that functional group. The term “functional group” generally refers to how persons of skill in the art classify chemically reactive groups. Examples of functional groups include hydroxyl, amine, sulfhydryl, amide, carboxylic acid, ester, carbonyl, etc. Protecting groups are well-known to those of skill in the art. Non-limiting exemplary protecting groups fall into categories such as hydroxy protecting groups, amino protecting groups, sulfhydryl protecting groups and carbonyl protecting groups. Such protecting groups, including examples of their installation and removal, may be found in Greene and Wuts (1999), incorporated herein by reference in its entirety. The starting materials, products and intermediates described herein are also contemplated as protected by one or more protecting groups—that is, the present invention contemplates such compounds in their “protected form,” wherein at least one functional group is protected by a protecting group. [0043] Compounds of the present invention may contain one or more asymmetric centers and thus can occur as racemates and racemic mixtures, single enantiomers, diastereomeric mixtures and individual diastereomers. In certain embodiments, a single diastereomer is present. All possible stereoisomers of the compounds of the present invention are contemplated as being within the scope of the present invention. However, in certain aspects, particular diastereomers are contemplated. The chiral centers of the compounds of the present invention can have the S- or the R-configuration, as defined by the IUPAC 1974 Recommendations. Thus, in certain aspects, compounds of the present invention may comprise S- or R-configurations at particular carbon centers. [0044] Persons of ordinary skill in the art will be familiar with methods of purifying compounds of the present invention. One of ordinary skill in the art will understand that compounds of the present invention can generally be purified at any step, including the purification of intermediates as well as purification of the final products. Purification procedures include, for example, silica gel column chromatography, HPLC, or crystallization. In particular embodiments, trituration is employed. In certain embodiments, solvent extraction is employed. [0045] Modifications or derivatives of the compounds disclosed throughout this specification are contemplated as being useful with the methods and compositions of the present invention. Derivatives may be prepared and the properties of such derivatives may be assayed for their desired properties by any method known to those of skill in the art. [0046] In certain aspects, “derivative” refers to a chemically-modified compound that still retains the desired effects of the compound prior to the chemical modification. Using W765-BG as an example, a “W765-BG derivative” refers to a chemically modified W765-BG that still retains the desired effects of the parent W765-BG prior to its chemical modification. Such effects may be enhanced (e.g., slightly more effective, twice as effective, etc.) or diminished (e.g., slightly less effective, 2-fold less effective, etc.) relative to the parent W765-BG, but may still be considered a W765-BG derivative. Such derivatives may have the addition, removal, or substitution of one or more chemical moieties on the parent molecule. Non-limiting examples of the types of modifications that can be made to the compounds and structures disclosed herein include the addition or removal of lower unsubstituted alkyls such as methyl, ethyl, propyl, or substituted lower alkyls such as hydroxymethyl or aminomethyl groups; carboxyl groups and carbonyl groups; hydroxyls; nitro, amino, amide, imide, and azo groups; sulfate, sulfonate, sulfono, sulfhydryl, sulfenyl, sulfonyl, sulfoxido, sulfonamide, phosphate, phosphono, phosphoryl groups, and halide substituents. Additional modifications can include an addition or a deletion of one or more atoms of the atomic framework, for example, substitution of an ethyl by a propyl, or substitution of a phenyl by a larger or smaller aromatic group. Alternatively, in a cyclic or bicyclic structure, heteroatoms such as N, S, or O can be substituted into the structure instead of a carbon atom. [0047] Salts of any of the compounds of the present invention are also contemplated. The term “salt(s)” as used herein, is understood as being acidic and/or basic salts formed with inorganic and/or organic acids and bases. Zwitterions (internal or inner salts) are understood as being included within the term “salt(s)” as used herein, as are quaternary ammonium salts, such as alkylammonium salts. Salts include, but are not limited to, sodium, lithium, potassium, amines, tartrates, citrates, hydrohalides and phosphates. [0048] Hydrates of compounds of the present invention are also contemplated. The term “hydrate” when used as a modifier to a compound means that the compound has less than one (e.g., hemihydrate), one (e.g., monohydrate), or more than one (e.g., dihydrate) water molecules associated with each compound, such as in solid forms of the compound. [0049] It is contemplated that any embodiment discussed in this specification can be implemented with respect to any method, compound, or composition of the invention, and vice versa. Furthermore, compounds and compositions of the invention can be used to achieve methods of the invention. [0050] The use of the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and/or.” [0051] Throughout this application, the term “about” is used to indicate that a value includes the standard deviation of error for the device or method being employed to determine the value. In any embodiment discussed in the context of a numerical value used in conjunction with the term “about,” it is specifically contemplated that the term about can be omitted. [0052] Following long-standing patent law, the words “a” and “an,” when used in conjunction with the word “comprising” in the claims or specification, denotes one or more, unless specifically noted. [0053] Other objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating specific embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. II. DISCUSSION OF GENERAL EMBODIMENTS [0054] Currently, MIBG based tumor imaging plays a critical role in the clinical staging and evaluation of therapeutic responses for neuroblastoma. MIBG can be selectively concentrated in more than 90% of neuroblastomas (Maris et al., 2007), and remains stable while circulating throughout the body (Papaioannou and McHugh, 2005). However, the extent of radiation exposure while using this agent in young patients is significant enough to cause secondary cancers in some cases. Therefore, it is necessary to develop an NIR imaging agent with the same functional characteristics as MIBG but without the use of radiation. In recent years, red-infrared excitable compounds and near-infrared excitable compounds have been used for molecular imaging due to the longer wavelengths at which they are detected to increase signal-to-background ratios. Cyanine dyes are commonly used as fluorophores for this purpose. The commercially available cyanine dye IRdye800CW was chosen as the NIR fluorescence contrast agent for this study because of its strong NIR signal intensity and its polarity, as the latter may aid in reducing the amount of imaging agent accumulated in the liver. [0055] The targeting moiety of the imaging agent was designed based on MIBG structure. It is known that MIBG is derived from neuron blocking agents. The MIBG structure combines the guanidine group from guanethidine and the benzyl portion from bretylium (Wieland, 1986). Structural alterations at the side chain of MIBG are critical for its binding specificity (Wieland, 1986; Vaidyanathan, 2008; Vaidyanathan, 2001). In general, benzyl ring substitutions are tolerated to a greater level than modifications on the guanidinomethyl functionality. The replacement at the meta or para position on the benzylguanidine ring maintain high affinities for the adrenal medulla (AM). The removal of iodine from MIBG had little effect on benzyl guanidine's accumulation in the adrenal medulla (Wieland, 1986; Vaidyanathan,1992). Therefore, W765-BG was designed based on meta substitution of benzylguanidine. [0056] The iodine functionality at the meta position of MIBG was replaced by an amino group coupled with glycine. One reason for this replacement was that the polar substituent on the aromatic ring may increase the excretion of the agent from normal tissue and enhance the tumor-to-background ratio. The reason for introducing an amino group coupled with glycine was that the resulting compound has a reactive primary amino functionality capable of conjugating with IRdye800CW. Finally, glycine was inserted as a spacer between the active component and the optical reporter to eliminate steric hindrance caused by the fluorophore, which might interfere with the ability of neuroblastoma cells to take up the compound. [0057] The properties of this newly developed benzyl guanidine analog (W765-BG) were characterized in the in vitro and in vivo studies. The relationship between neuroblastoma cells, as well as the neuroblastoma cells and W765-BG or the free NIR dye was determined in vitro by NIR confocal microscope. A high uptake of optical imaging agent W765-BG in neuroblastoma cell was observed by cell study. FIG. 1 shows a side by side cell binding comparison between these imaging agents at single cell level. As shown in FIG. 1 , not only does the imaging agent cross the cell membrane and pass through cytoplasm, but the imaging agent is internalized into the cell nuclei ( FIG. 1 , top panel, (b) and (c)). There was almost no detectable signal in cell from free dye ( FIG. 1 , bottom panel, (b) and (c)). This data demonstrates that W765-BG targets neuroblastoma. [0058] The selectivity of W765-BG was further explored through the in vivo studies using luciferase-positive human neuroblastoma xenografts in mice. FIG. 2 shows four different kinds of images (white light, X-ray, NIR and luciferase) of the same tumor-bearing mouse 48 hours after administration of the imaging agents. The NIR image revealed that W765-BG accumulates in cell inoculation site where the tumor can be visualized by other three images (white light, X-ray and luciferase imaging). Importantly, W765-BG was detected in tumor region only. This result confirms that W765-BG is highly selective for neuroblastoma. Furthermore, it was observed that W765-BG optical signals were retained in the tumor for about 48 hours after injection, after which the optical signal strength gradually diminished. The tumor to background ratios for 24, 48 and 192 hours were 1.95, 1.98, and 1.52, respectively. This permits imaging at prolonged intervals after injection. [0059] W765-BG is specific for neuroblastoma cells and is readily accumulated in neuroblastoma cells. Since, W765-BG can be visualized at the cellular level makes W765-BG a valuable tool for mechanistic studies and in vitro cellular tracking experiments. Furthermore, unlike radiolabeled MIBG, which has to be used immediately after manufacture because of its short half-life, W765-BG can be pre-synthesized and stored over a long period of time, eliminating the time constraint between manufacture and use. [0060] The cell uptake of W765-BG requires more time by neuroblastoma cells suggests this is not receptor-ligand process rather through a metabolic mechanism. The metabolic uptake requires a much longer time for the signals from the agent to be detected in the cells, compared with receptor-ligand or antigen-antibody binding. The cell metabolic conditions also affect the capability of the uptakes. This uptake variance is reflected in the in vivo imaging study results. Using confocal microscopy and collecting more than one channel signal from a single cell slice is important to validate the relationship among multiple signals. [0061] The W765-BG compound is both sensitive and specific for neuroblastoma in the xenograph mouse model. Neuroblastoma specific uptake and visualization using this near-IR dye conjugated analog of benzyl guanidine detected tumors developed from three different cell line. This compound also has a prolonged imaging window after injection suggesting that it accumulates in neuroblastoma tissue and is slowly metabolized or excreted from neuroblastoma cells. Once absorbed, strong tumor specific optical signals were found to persist longer than one week. These findings support the proposition that IR imaging can overcome the limitations of radiolabeled MIBG for neuroblastoma imaging studies as well as provide a more complete understanding of these tumors. [0062] Earlier near-IR imaging has demonstrated feasibility for whole body imaging with a tissue penetration depth sufficient for metastasis and primary tumor detection without ionizing radiation. Radio-labeled MIBG must be synthesized immediately prior to use which is costly and logistically difficult in the clinical setting and severely limits its use for in vitro studies. In contrast W765-BG has a long shelf life facilitating and prolonged imaging window (up to 8-9 days post injection). [0063] W765-BG imaging is specific for tumors in the retroperitoneal area. Normal renal structures did not take up the compound. Limited uptake of W765-BG in the kidney region is important because the adrenal gland is the most common location for neuroblastoma. Furthermore, the W765-BG signal intensity in the liver is much lower than other agents that have been reported thus far. This mouse model did not develop liver or bone metastases which are important locations for clinical applications. Therefore the sensitivity for detecting tumor in those areas remains unknown. However the low W765-BG background signal in the whole body images suggests that uptake in distant sites is tumor specific. [0064] The W765-BG images illustrate quite different tumor growth patterns after inoculation. Neuroblastoma xenografts reflect the heterogeneity of clinical tumors with different growth rates, degrees of vascularity and apoptotic rates. For example, NGP is localized with clear margins whereas the NB 1691 tumors have much more diffuse margins. Dissection and pathological analysis showed necrotic tissue in the low signal intensity part of the tumor. This data suggest that W765-BG is taken up only by viable cells. When combined with RGD 5.5 vascular imaging, the tumor boundaries and regions of neovasculargenesis were better defined ( FIG. 5 ). Further studies with this mode of imaging may help to understand responses to antiangiogenic and other types of targeted therapies in the xenograft setting. [0065] Relative to W765-BG, the lack of homogeneity of luciferase over serial observations suggest that luciferase imaging can be a highly variable measure of tumor size. It is unusual to observe heterogeneous luciferase signal intensity inside a tumor in published luciferase images. It is believed that the reason it was possible to detect regional differences in single tumors was at least partly due to the use of a high resolution and high dynamic range of the CCD in the optical imaging system used in this study. This camera system provides very high image acuity and is sensitive enough to vividly discriminate many levels of signal from background noise without saturating the detector. [0066] The cell uptake of W765-BG requires more time by neuroblastoma cells suggest this is not a receptor-ligand process, but a metabolic mechanism. The metabolic uptake requires a much longer time for the signals from the agent to be detected in the cells, compared with receptor-ligand or antigen-antibody binding. The cell metabolic conditions also affect the capability of the uptakes. This uptake variance is reflected in the in vivo imaging studies. Using confocal microscopy and collecting more than one channel signal from a single cell slice is important to validate the relationship among multiple signals. [0067] It is well known that tumors are heterogeneous. The luciferase images illustrate the different tumor growth patterns after inoculation. Even with two lines of cells that are derived from the same disease, one is localized with clear margins and the other is diffused without margins. These types of imaging findings may be used in clinical decisions regarding tumor staging and treatment. The localized tumor with clear margins may be treated with surgery and/or radiation. On the other hand, the diffused tumor may not be treated with surgical methods because it may be difficult to achieve a clear margin. The high interstitial pressure in the solid tumor may confound chemotherapy because the agents cannot penetrate into the tumor mass. The images provided herein illustrate that such solid tumors may even prevent a small peptide, like RGD, from penetrating into the tumor mass. The other possibility is that this tri-peptide agent does not match this disease at this stage. [0068] The current disclosure provides a novel approach to imaging neuroblastoma tumors using an analogue of MIBG. It was demonstrated that tumor specific uptake was done with a very low background. Multi-agent and multi-wavelength optical imaging used helped to define the interactions among tumor cells, tumor vasculature, and tumor-specific imaging agents. Near-IR optical imaging of neuroblastoma using the imaging agent disclosed herein provides several clinical uses and advantages over standard I 123 MIBG imaging. These properties open new possibilities in both in vitro and in vivo studies. III. EXAMPLES [0069] The following examples are included to demonstrate preferred embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventor to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention. Example 1 Methods and Materials [0070] Cell lines. Human neuroblastoma cancer cell lines NB1691.1uc and SYFY.luc were cultured in Dulbecco's Modified Eagle's Medium supplemented with high glucose and F12 nutrient (DMEM/F12, Invitrogen, Carlsbad, Calif.) with 10% fetal bovine serum (Hyclone, Logan, Utah) in a humidified incubator maintained at 37° C. with 5% CO 2 . [0071] Tumor xenografts: Four- to six-week-old female nude mice (18-22 g) (Taconic, Hudson, N.Y.) were housed and fed with sterilized pellet chow and sterilized water. Animals were maintained in a pathogen-free mouse colony. Tumor cells near confluence were harvested by incubation with 0.05% trypsin-EDTA. Cells were pelleted by centrifugation at 130×g for 5 min and resuspended in sterile phosphate-buffered saline (PBS). Approximately 1 million cells were implanted subcutaneously into the hind leg region of the mice. A total of 15 mice was used in this study. [0072] Confocal microscope imaging. Cells were harvested from culture and incubated overnight at 37° C. with W765-BG imaging agent or NIR dye at final concentrations of 50 μmolar. Cells were washed in PBS, then incubated for 15 min at 4° C. with Sytox green (Molecular Probes) in 95% ethanol to fix the cells and stain cell nuclei. Stained cells were then transferred to a slide and mounted for microscopic examination. Images were recorded using an Olympus confocal microscope (Model: Fluorview 1000, Olympus America, Center Valley, Pa., USA). The microscope was equipped with excitation (Ex) light source and emission (Em) filters to detect and separate W765-BG or NIR dye (ex/em 765/810 nm) and cell nuclei (ex/em 488/510 nm) signals. In the microscopic images, signal intensities were recorded from one slice of 23 cell z-stacks with 0.5 micrometers gaps. Sytox green and W765-BG or NIR dye signals were pseudo colored into green (emission at 510 nm) and red (emission at 810 nm), respectively. [0073] Animal imaging. Tumors were visualized by intraperitoneal injection of 3 mg of VivoGlo Luciferin (Promega, Madison Wis.) before the imaging session, and pseudo into cyan. Ten nanomoles of W765-BG and 3 nanomoles of the vascular agent RGD-Cy5.5 were injected i.v. into the tumor-bearing mice prior to the imaging study. The animals were imaged 1 to 9 days after the injection using the Kodak In-Vivo Multispectral System FX (Carestream Health Molecular Imaging, New Haven, Conn.). Vasculature images were recorded at wavelengths of ex/em 650/700 nm for RDG-Cy5.5 and pseudo colored into red. The W765-BG signal was recorded at wavelengths of ex/em 770/830 nm and pseudo colored into green. Tumor cells, vasculature, and W765-BG signals were precisely overlaid with anatomical X-ray images. [0074] Chemicals. Boc-glycine-OSu was purchased from Chem-Impex International (Wood Dale, Ill.). 3-aminobenzyl alcohol, N,N-diisopropylethylamine (DIPEA), triethylsilane (TES), 1,3-Bis(tert-butoxycarbonyl)guandine, triphenylphosphine (TPP), and diidsopropyl azo-dicarboxylate (DIAD) were purchased from Sigma-Aldrich (St. Louis, Mo.). Trifluoroacetic acid (TFA) and all other reagents and solvents were purchased from VWR (San Dimas, Calif.). IRdye800cw and IRdye800cw carboxylate were purchased from Li-Cor (Lincoln, Neb.). [0075] Compound Analyses. Analytical high-performance liquid chromatography (HPLC) was performed on an Agilent 1100 HPLC system equipped with a Varian reverse phase C-18 analytical column (R0086200CG) at a flow rate of 1 mL/min. Samples were eluted with H 2 O/acetonitrile containing 0.1% TFA with three different linear gradients (A: 0-20% in 10 min; B: 0-40% in 30 min; C: 10-80% in 30 min.). Preparative HPLC was performed on a Varian Prostar 210 HPLC equipped with a 25×2.5-cm Varian reverse phase C-18 preparative column (R0080220CB). Matrix-assisted laser desorption ionization mass spectrometry (MALDI) and electrospray ionization mass spectrometry (ESI) were performed by the Protein Chemistry Core Laboratory at Baylor College of Medicine. Nuclear magnetic resonance (NMR) was performed by CCSG Shared Resources at M.D. Anderson Cancer Center. Example 2 Synthesis of W765-BG [0076] The reaction scheme and structure of W765-BG is shown in Scheme 1. The synthesis procedure was carried out in four steps. Compound 1 (3-aminobenzyl alcohol) was reacted with Boc-Gly-OSu under basic conditions to form 3-(Boc-Gly-amino)benzyl alcohol (Compound 2). By means of the Mitzunobu protocol (Dodd and Kozikowski, 1994), compound 2 was converted to 1,3-bis(tert-butyloxycarbonyl)-2-(3-(Boc-Gly-amino)benzyl)guanidine (compound 3) by treatment with N,N-bis-Boc-guandine, triphenylphosphine, and diidsopropyl azo-dicarboxylate. Three Boc-protecting groups on compound 3 were removed under acidic conditions, resulting in compound 4. This compound was conjugated to IRdye800cw through the α-amino functional group of glycine to result in the NIR optical imaging agent W765-BG. [0000] [0077] Synthesis of 3-(Boc-Gly-amino)benzyl alcohol (Boc-Gly-NH-Bn-OH) (Compound 2): 3-aminobenzyl alcohol (123 mg, 1 mmol) and Boc-Gly-OSu (272 mg, 1 mmol) were dissolved in 5 mL of DMF. DIPEA (0.2 mL) was added to the solution, and the mixture was stirred overnight at room temperature. After evaporation of the solvents under vacuum, the residue was dissolved in ethyl acetate, washed with 5% NaHCO 3 , 2% KHSO 4 , and brine. Solvents were removed under vacuum. The solid was further purified by reverse phase HPLC with water and acetonitrile as eluent, and dried by lyophilization to yield Compound 2, which was validated by NMR and analytic HPLC. 1H NMR (CDCl 3 ): 1.49 (s, 9H), 3.93 (s, 2H), 4.65 (s, 2H), 5.45 (b, 1H), 7.07 (d, 1H), 7.25-7.30 (m, 2H), 7.41 (d, 1H), 8.46 (b, 1H); HPLC (gradient C) retention time 10.98 min. [0078] Synthesis of 1,3-bis(tert-butyloxycarbonyl)-2-(3-(Boc-Gly-amino)benzyl)guanidine [Boc-Gly-NH-Bn-G(Boc) 2 ] (Compound 3): Compound 2 (140 mg, 0.5 mmol), 1,3-Bis(tert-butoxycarbonyl)guandine (259 mg, 1 mmol), and TPP (275 mg, 1.1 mmol) were dissolved in 5 mL of THF. DIAD (203 mg, 1 mmol) was added dropwise to the solution, and the mixture was stirred overnight at room temperature. The THF was evaporated under vacuum, and the residue was purified by flash chromatography using ethyl acetate/hexane as eluent, to yield Compound 3, which was validated by NMR, Mass and analytic HPLC. 1H NMR (CDCl 3 ): 1.39 (s, 9H), 1.49 (s, 18H), 3.93 (s, 2H), 5.15 (s, 2H), 5.26 (b, 1H), 6.94 (d, 1H), 7.21-7.27 (m, 2H), 7.46 (d, 1H), 8.17 (b, 1H), 9.51 (b, 1H); Mass for C 25 H 39 N 5 O 7 calculated. [M] + 521.28; found 522.2; HPLC (gradient B) retention time 7.09 min. [0079] Synthesis of 2-(3-(Gly-amino)benzyl)-guanidine (Gly-NH-BG) (Compound 4): Compound 3 (130 mg, 0.25 mmol) was dissolved in 2 mL of 50% TFA in dichloromethane for 1 hr at room temperature. The solvent was evaporated under vacuum, and the residue was purified by reverse phase HPLC with water and acetonitrile containing 0.1% TFA as eluent. The sample was lyophilized to yield Compound 4, which was validated by NMR, Mass and analytic HPLC. 1H NMR (DMSO): 3.78 (s, 2H), 4.37 (d, 2H), 7.02 (d, 1H), 7.33-7.39(m, 3H), 8.12-8.14(m, 4H), 10.51(s, 1H); Mass for C 10 H 15 N 5 O calculated. [M] + 221.13; found 222.1; HPLC (gradient A) retention time 6.68 min. [0080] Synthesis of 2-(3-(IRdye800-Gly-amino)-benzyl)guanidine (W765-BG) (Compound 5): Conjugation of IRdye800cw (5 mg, 0.004 mmol) to the amino group of Gly in 2-(3-(Gly-amino)benzyl)guanidine (2.33 mg, 0.01 mmol), was carried out in a DIPEA/DMF(1/9) solution for 2 hr at 4° C. The solvent was removed under vacuum and the residue was washed with ether several times. The solid was purified by reverse phase HPLC and dried by lyophilization to yield W765-BG. The compound was validated by Mass and analytic HPLC. MALDI for C 56 H 68 N 7 O 15 S 4 + calculated [M] + 1206.37, found 1206.36; HPLC (gradient B) retention time 19.86 min. Example 3 Imaging using W765-BG [0081] Imaging of W765-BG in neuroblastoma cells. To evaluate W765-BG as a potential specific molecule, its ability to uptakes by neuroblastoma cells was examined in vitro by NIR confocal microscopy. NPG.Luc cells were treated with W765-BG or free dye overnight at 37° C., after which they were washed, fixed, and visualized by confocal microscopy. W765-BG was detected inside the cells ( FIG. 1 , top panel), while there was almost no detectable signal in cells treated with the free dye (IRDye800CW carboxylate) alone ( FIG. 1 , bottom panel). This data confirms that W765-BG is taken up by neuroblastoma cells. The merged confocal images clearly demonstrate that W765-BG is located inside the cell and in the nuclear compartment. [0082] Imaging of W765-BG in human tumor xenografts in mice. To further demonstrate the feasibility of imaging neuroblastomas using W765-BG, luciferase-positive tumor cells (NGP.Luc) were implanted subcutaneously into the hind region of mice. Tumor-bearing mice received an intraperitoneal injection of Luciferin to visualize the tumor cells, followed by an intravenous injection of W765-BG from the tail vein. Whole body images were collected at 24 h intervals over the course of eight days. Tumors were visualized by white light, X-ray and luciferase imaging ( FIG. 2 ). W765-BG accumulated in the tumor ( FIG. 2C ), as demonstrated by NIR imaging. When merging the optical signal of W765-BG with luciferase and anatomic X-ray images ( FIG. 2E-2F ), their precise overlay confirms the specificity of W765-BG. [0083] In vitro cell uptake imaging agent. Imaging agent uptake by the cells was recorded by confocal microscopy. The cell population view is shown in FIG. 3 (A to D). The images show cell morphology ( FIG. 3A ), cell nuclei ( FIG. 3B ), and W765-BG uptakes by cells ( FIG. 3C ). The merged image ( FIG. 3D ) shows that W765-BG was internalized into cells, and co-located with nuclei (yellow color). FIG. 3E to FIG. 3H shows a side-by-side confocal imaging study to compare W765-BG and NIR dye uptake at the single-cell level. The merged morphological and NIR images show that the W765-BG signals were coming from the cell ( FIG. 3E ), while there was almost no detectable signal in the cells that were incubated with NIR dye in the same imaging setting ( FIG. 3F ). Those results were validated by non-overlaid NIR images ( FIG. 3G and FIG. 3H ). [0084] In vivo imaging. Luciferase positive tumor cell could be detected as early as 4 days after inoculation (data not show). Different tumor growth patterns were detected at 7 days post inoculation. NB1691.Luc cells formed a localized node with a clear margin ( FIG. 4A ). The vasculature image shows a dark centralized region (arrow in FIG. 4B ) in the same area. The signal-to-background ratio (TBR) of 0.79 quantitatively demonstrates the lack of vasculature agent in this region. A similar effect was observed in the W765-BG image, with a TBR=0.95 (arrow in FIG. 4C ). The merged image shows that the tumor mass fits into this low signal region ( FIG. 4D ). The anatomic image shows the W765-BG whole body distribution ( FIG. 4E ). FIG. 4F shows the relationship among the tumor cell, vasculature imaging agent, tumor imaging agent and anatomic structure. [0085] In contrast, the NGP.Luc tumor was rather diffuse without a clear margin in the early tumor growth phase ( FIG. 4G ). The tumor vasculature developed better than in the NB1691.Luc tumor. This resulted in a higher TBR of 1.13 from the RGD-Cy5.5 agent ( FIG. 4H ). The diffused tumor growth pattern also limited the W765-BG imaging findings in this stage ( FIG. 4I ). Once again, the merged images show the location of the tumor cells and the vasculature status ( FIG. 4J to FIG. 4L ). One week later, the tumor cells became more concentrated in one location ( FIG. 4M ). The vasculature surrounding the tumor node was well formed ( FIG. 4N ) and the TBR of the vasculature agent increased to 1.90. The signal intensity of W765-BG was significantly higher in the tumor region than the background and the TBR increased to 2.90 ( FIG. 4O ). The two imaging agents were distributed differently in the body ( FIG. 4P ). The vasculature imaging agent RGD was in the kidney and the periphery of the tumor, while W765-BG was in the tumor. Merged X-ray and W765-BG images confirmed the tumor size, location and W765-BG signal intensity ( FIG. 4Q ). Finally, FIG. 4R vividly shows the mouse anatomic structure, tumor location, and the distribution of two imaging agents. [0086] Late stage tumor, organ image and pathological analysis. Late stage tumor mass and organ imaging were performed after the injection of additional imaging agent ( FIG. 5A-H ). The color photograph ( FIG. 5A ) shows the tumor on the left hind leg of the animal. The majority of the vasculature agent signal was concentrated in the kidney region ( FIG. 5B ), while W765-BG signals were non-uniformly distributed in the tumor ( FIG. 5C ). A luciferase image of tumor cells also shows uneven signals in the tumor region ( FIG. 5D ). The dissected animal and organ layout is shown in FIG. 5E . The organ images show the vasculature agent localized in the kidney ( FIG. 5F ), confirming the whole body imaging results. The dissected organ images show W765-BG in the tumor, liver and spleen ( FIG. 5G ). The merged image shows the different organ distribution of the two agents ( FIG. 5H ). Gross necropsy confirmed the necrosis in the center of this tumor. H&E stain confirmed the identification of tumor ( FIG. 5I ), muscle ( FIG. 5J ), liver ( FIG. 5K ), kidney ( FIG. 5L ), and spleen ( FIG. 5M ) at pathological levels. [0087] Imaging window and cell type difference. The tumor to background ratio (TBR) was used to determine the optimal imaging time and cell type variance for W765-BG. The TBR is statistically higher at 24 hours after the injection compared with 192 hours (p=0.0196). There was no statistically significant difference in TBR between 24 and 48 hours (P=0.1985) or between 48 and 192 hours (P=0.1574) after injection of this agent in the imaging studies. The results suggested a wide imaging window to achieve consistent data. The data variation also decreased in the 192-hour imaging point compared with the 24-hour. There was a statistically significant difference between the 24 and 192 hours images ( FIG. 6A ). [0088] As shown in FIG. 6B , significant differences were found among the three cell lines. NGP.Luc cells had a significantly higher uptake capability than NB1691 .Luc (p=0.0261) and SYSY.Luc (p=0.0052). There was no statistical difference between NB1691.Luc and SYSY.Luc (p=0.6613). The best cell line for specific agent binding was the NGP.Luc cells ( FIG. 6B ). Example 4 Imaging Agents [0089] In some examples, the meta-functionalized benzyl guanidine, is linked to the non-radioactive dye through a general linker moiety. This general linker moiety is composed of a spacer moiety and two connecting functionalities which are chemically bonded to the meta-functionalized benzyl guanidine and the dye. In specific examples, the chemical bond connecting the meta-functionalized benzyl guanidine and the linker moiety is an amide, amine, ester, ether, thioester, a carbon-carbon single bond, a carbon-carbon double bond, or a carbon-carbon triple bond. In specific examples, the spacer moiety of the liker is a functionalized alkyl (C=1-8) , alkenyl (C=1-8) , or an aralkyl (C=1-8) , or substituted versions of any of these moieties. In general, the dye is a contrast agent. In a particular example, the dye is a flurophore. [0090] The imaging agent has the following general structure: [0000] [0091] In the general formula for the imaging agent, the general linker moiety is represented by X-R-Y. In some examples, X is chemically bonded to benzyl guanidine through amide, amine, ester, ether, thioether, carbonyl, a carbon-carbon single bond, a carbon-carbon double bond, or a carbon-carbon triple bond. The spacer moiety is represented by R. In some instances, R is alkyl (C=1-8) , alkenyl (C=1-8) , or aralkyl (C=1-8) , or a substituted version of any of these groups. The type of chemical bond used to connect the spacer moiety to the dye may be varied. This chemical bond is represented by Y. In some cases, the spacer moiety is bonded to the dye through an amide or a thioether bond. In specific examples, the dye is IRdye800CW, IRdye800RS, or IRdye700DX. [0092] In general, the imaging agent can be synthesized in four major steps, as shown in Scheme 2. Although Scheme 2 only shows the four major steps, one of ordinary skill in the art would readily recognize that steps such as protections, deprotections and the arrangement of the synthetic process can be modified to arrive at the same imaging agent. For example, in some cases it may be synthetically advantageous to perform step 4 before step 2 or step 3 in order to facilitate purification. In some cases, it may be advantageous to use a protecting agent other than -Boc. There are a wide range variations that can be made to the synthetic route shown in Scheme 2 and still be within the scope of the present invention. [0000] [0093] In general, Step 1 comprises coupling the meta-functionalized benzyl alcohol and the linker moiety. The meta-functionalized benzyl alcohol and the linker moiety may be coupled through an amide, an amine, an ester, an ether, thioether, carbon-carbon single bond, carbon-carbon double bond, or a carbon-carbon triple bond. [0094] In the specific example shown below, the meta-functionalized benzyl alcohol is coupled to the linker moiety through an amide bond. [0000] [0095] In this specific example, the coupling is accomplished through a two step process. The reaction conditions for the first step include adding N,N′-diisopropylcarbodiimide (DIC) and N-Hydroxysuccinimide (HOSu) to the linker moiety. In this example, the linker moiety is a carboxylic acid represented by the formula R 4 —R 3 —COOH. The second step of the coupling process includes treating the reaction mixture with a base at room temperature. [0096] In some examples R 1 is hydrogen or trityl (Trt). In specific examples R 3 —COOH is glycine, alanine, valine, phenylalanine, leucine, 3-aminopropanoic acid, 4-aminobutanoic acid, 5-aminopentanoic acid, 6-aminohexanoic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 4-aminobenzoic acid, 4-mercaptobenzoic acid, 2-mercaptoacetic acid, or 3-mercaptopropanoic acid. In some examples, R 4 is 9-fluorenylmethoxycarbonyl (Fmoc) or tert-butyloxycarbonyl (t-Boc or Boc). [0097] In the specific example shown below, the meta-functionalized benzyl alcohol is coupled to the linker moiety through an amine bond. [0000] [0098] In this specific example, the coupling is accomplished through an one step process. The reaction conditions for this coupling include reacting the meta-halo-functionalized benzyl alcohol with a primary amine represented by the formula R 4 —R 3 —NH 2 in the presence of a base. [0099] In some examples R 1 is hydrogen or trityl (Trt) and R 2 is a halogen. In specific examples, R 2 is Chlorine or Bromine. In specific examples, R 3 —NH 2 is ethane-1,2-diamine, propane-1,3-diamine, pentane-1,5-diamine, hexane-1,6-diamine. In some examples, R 4 is 9-fluorenylmethoxycarbonyl (Fmoc) or tert-butyloxycarbonyl (t-Boc or Boc). [0100] In the specific example shown below, the meta-functionalized benzyl alcohol is coupled to the linker moiety through an ester bond. [0000] [0101] In this specific example, the coupling is accomplished through an one step process. The reaction conditions for this coupling include reacting the meta-hydroxy-functionalized benzyl alcohol with a carboxylic acid represented by the formula R 4 —R 3 —COOH, N,N′-diisopropylcarbodiimide (DIC) and 4-Dimethylaminopyridine (DMAP) at room temperature. [0102] In some examples R 1 is hydrogen or trityl (Trt). In specific examples, R 3 —COOH is glycine, 3-aminopropanoic acid, 4-aminobutanoic acid, 5-aminopentanoic acid, 6-aminohexanoic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 4-aminobenzoic acid. In some examples, R 4 is 9-fluorenylmethoxycarbonyl (Fmoc) or tert-butyloxycarbonyl (t-Boc or Boc). [0103] In the specific example shown below, the meta-functionalized benzyl alcohol is coupled to the linker moiety through an ether bond. [0000] [0104] In this specific example, the coupling is accomplished through a multistep process. The first step involves coupling of the meta-hydroxy-functionalized benzyl alcohol with either a cyano-functionalized alkyl halide or a cyano-functionalized alkene in the presence of a base followed by treating the resulting mixture with a borane-tetrahydrofuran complex (BH 3 -THF). In specific examples, the cyano-functionalized alkyl halide is BrCH 2 CN and the cyano-functionalized alkene is CH 2 ═CHCN. The resulting primary amine is then coupled to a carboxylic acid represented by the formula R 4 —R 3 —COOH using N,N′-diisopropylcarbodiimide (DIC) and 4-Dimethylaminopyridine (DMAP) at room temperature followed by treating the resulting reaction mixture with a base. [0105] In some examples R 1 is trityl (Trt). In specific examples, when the cyano-functionalized alkyl halide is BrCH 2 CN, R 5 is (CH 2 ) 2 NH 2 , and when the cyano-functionalized alkene is CH 2 ═CHCN, R 5 is —(CH 2 ) 3 NH 2 . In some examples, R 3 may or may not be present. When R 3 is not present the coupling agent is N-(9-Fluorenylmethoxycarbonyloxy) succinimide (Fmoc-Osu). In specific examples, R 3 —COOH is glycine, alanine, valine, phenylalanine, leucine, 3-aminopropanoic acid, 4-aminobutanoic acid, 5-aminopentanoic acid, 6-aminohexanoic acid, 7-aminoheptanoic acid, or 8-aminooctanoic acid. In some examples, R 4 is 9-fluorenylmethoxycarbonyl (Fmoc) or tert-butyloxycarbonyl (t-Boc or Boc). [0106] In the specific example shown below, the meta-functionalized benzyl alcohol is coupled to the linker moiety through a thioether bond. [0000] [0107] In this specific example, the coupling is accomplished through a two step process. The first step involves coupling of the meta-halo-functionalized benzyl alcohol with a thiol represented by the formula R 5 —SH in the presence of a base. In general the R 5 functional group contains a reactive carboxylic acid moiety. The second step involves the reacting the reactive carboxylic acid with an amine represented by the formula R 4 —R 3 —NH 2 , N,N′-diisopropylcarbodiimide (DIC) and N-Hydroxysuccinimide (HOSu). [0108] In some examples R 1 is hydrogen or trityl (Trt) and R 2 is a halogen. In specific examples, R 2 is Chlorine or Bromine. In specific examples, R 5 —SH is 4-mercaptobenzoic acid, 2-mercaptoacetic acid or 3-mercaptopropanoic acid. In specific examples, R 3 —NH 2 is ethane-1,2-diamine, propane-1,3-diamine, pentane-1,5-diamine or hexane-1,6-diamine. In some examples, R 4 is 9-fluorenylmethoxycarbonyl (Fmoc) or tert-butyloxycarbonyl (t-Boc or Boc). [0109] In the specific example shown below, the meta-functionalized benzyl alcohol is coupled to the linker moiety through a carbon-carbon single bond. [0000] [0110] In this specific example, the coupling is accomplished through a two step process. The first step involves coupling of the meta-halo-functionalized benzyl alcohol with a lithium dialkyl copper reagent ((R 5 ) 2 CuLi) in tetrahydrofuran (THF) at −78° C. In general the lithium dialkyl copper reagent comprises a R 5 functional group further comprising a terminal halide. The second step involves the reacting the resulting terminal halide with an amine represented by the formula R 4 —R 3 —NH 2 , in the presence of a Pentamethylcyclopentadienyl)iridium(III) chloride dimer and a base, at reflux. [0111] In some examples R 1 is hydrogen or trityl (Trt). In general, R 5 is an alkyl halide. In specific embodiments, R 5 is bromobutane (—(CH 2 ) 4 Br), or bromoethane (—(CH 2 ) 2 Br). In some examples, R 3 —NH 2 is ethane-1,2-diamine, propane-1,3-diamine, pentane-1,5-diamine, or hexane-1,6-diamine. In some examples, R 4 is 9-fluorenylmethoxycarbonyl (Fmoc) or tert-butyloxycarbonyl (t-Boc or Boc). [0112] In the specific example shown below, the meta-functionalized benzyl alcohol is coupled to the linker moiety through a carbon-carbon double bond. [0000] [0113] In this specific example, the coupling is accomplished through a two step process. The first step involves coupling of the meta-halo-functionalized benzyl alcohol with an alkene having the general formula R 5 —C═CH 2 , triphenylphosphine (PPh 3 ), palladium acetate (Pd(OAc) 2 ), a base, at about 150° C. The second step involves adding the resulting alkene with a primary amine represented by the formula R 4 —R 3 —NH 2 , N,N′-diisopropylcarbodiimide (DIC) and N-Hydroxysuccinimide (HOSu) to give the meta-functionalized benzyl alcohol coupled to the linker moiety through a carbon-carbon double bond. [0114] In some examples R 1 is trityl (Trt). In general, the formula R 5 —CH═CH 2 represents an alkene with a reactive carboxylic acid functionality. In particular examples, R 5 —CH═CH 2 is HOOC—CH═CH 2 . In specific examples, R 3 —NH 2 is ethane-1,2-diamine, propane-1,3-diamine, pentane-1,5-diamine, and hexane-1,6-diamine. In some examples, R 4 is 9-fluorenylmethoxycarbonyl (Fmoc) or tert-butyloxycarbonyl (t-Boc or Boc). [0115] In the specific example shown below, the meta-functionalized benzyl alcohol is coupled to the linker moiety through a carbon-carbon triple bond. [0000] [0116] In this specific example, the coupling is accomplished through a two step process. The first step involves coupling of the meta-halo-functionalized benzyl alcohol with an alkyne. This reaction involves the addition of the meta-halo-functionalized benzyl alcohol with an alkyne represented by the formula R 5 —C≡CH, pyrrolidine, tetrakis(triphenylphosphine) Palladium (Pd(PPh 3 ) 4 ), Copper(I)iodide (CuI), at about 70° C. The second step involves adding the resulting alkyne to a primary amine represented by the formula R 4 —R 3 —NH 2 , a Pentamethylcyclopentadienyl)iridium(III) chloride dimer and a base at reflux. [0117] In some examples R 1 is trityl (Trt). In general, the formula R 5 —C≡CH represents a hydroxy functionalized alkyne. In a specific example, the formula R 5 —C≡CH represents HOCH 2 —C≡CH. In specific examples, R 3 —NH 2 is ethane-1,2-diamine, propane-1,3-diamine, pentane-1,5-diamine, or hexane-1,6-diamine. In some examples, R 4 is 9-fluorenylmethoxycarbonyl (Fmoc) or tert-butyloxycarbonyl (t-Boc or Boc). [0118] Generally in Step 2, the meta-functionalized benzyl alcohol is converted to the meta-functionalized benzyl guanidine as shown in the scheme below. [0000] [0119] In this specific example, converting the meta-functionalized benzyl alcohol to the meta-functionalized benzyl guanidine may be accomplished in a single step or through a two step process. In specific examples, the meta-functionalized benzyl alcohol is protected and R 1 is a trityl group (Trt). When the meta-functionalized benzyl alcohol is protected with a trityl group, the first step is a deprotection step which removes the trityl group. This step involves treating the protected meta-functionalized benzyl alcohol with 1% trifluoroacetic acid (TFA) in dichloromethane (DCM). When R 1 is hydrogen, this deprotection step is not necessary. [0120] The deprotected meta-functionalized benzyl alcohol is then treated with N,N-bis-Boc-guanidine, triphenylphosphine (TPP), and diisopropyl azodicarboxylate (DIAD) in tetrahydrofuran (THF) to generate the meta-functionalized benzyl guanidine. [0121] In Step 3 of the synthetic process, the protecting groups are removed as shown in the scheme below. [0000] [0122] In specific examples, the protecting groups are removed by treating the meta-functionalized benzyl guanidine with 50% trifluoroacetic acid (TFA) in dichloromethane (DCM) for removing Trt and Boc protecting groups. In other examples when the protecting group is Fmoc, the protecting group is removed by treating the meta-functionalized benzyl guanidine with 20% piperidine in dimethylformamide (DMF). [0123] In particular examples, X is —NHCO—, —NH—, —OCO—, —O—, —S—, —CH 2 CH 2 —, —CH═CH—, or —C≡C—. In general, R is alkyl (C=1-8) , alkenyl (C=1-8) , or aralkyl (C=1-8) , a substituted version of any of these groups, or a substituted and functionalized version of any of these groups. In specific examples, R 6 is —NH 2 or —SH. [0124] In step 4 of the synthetic route, a dye is conjugated to the benzyl guanidine analog as shown in the scheme below. [0000] [0125] In some examples, the dye is conjugated to the benzyl guanidine analog in one step. In general, this step involves treating the benzyl guanidine analog with a dye, a base at room temperature to give the desired imaging agent. [0126] In particular examples, X is —NHCO—, —NH—, —OCO—, —O—, —S—, —CH 2 CH 2 —, —CH═CH—, or —C≡C—. In general, R is alkyl (C=1-8) , alkenyl (C=1-8) , or aralkyl (C=1-8) , a substituted version of any of these groups, or a substituted and functionalized version of any of these groups. In specific examples, R 6 is —NH 2 or —SH. In specific examples, the dye is IRdye800CW, IRdye800RS, or IRdye700DX when the benzyl guanidine analog is coupled to the dye through an amino functional group, and the dye is IRDye 800CW Maleimide when the benzyl guanidine analog is coupled to the dye through a thiol functional group. [0127] In a specific example, X is an amide, R is glycine, R 6 is a carboxylic acid functionalized five carbon alkyl chain and the dye is IRdye800CW and the composition has the formula: [0000] IV. REFERENCES [0128] The following references, to the extent that they provide exemplary procedural or other details supplementary to those set forth herein, are specifically incorporated herein by reference. [0129] Dodd, D. S., and Kozikowski, A. P. (1994) Tetrahedron Letters 35, 977. [0130] Estorch, M. Eur. J. Nucl. Med. Mol. Imaging, (2006), 33, 246-247. [0131] Henneman, M. M., Bax, J. J., and Van der Wall, E. E. Eur. Heart J., (2007), 28: 922-923. [0132] Howman-Giles, R., Shaw, P. J., Uren, R. F., and Chung, D. K. Semin. Nucl. Med., (2007), 37(4), 286-302. [0133] Kaste, S. C. Pediatr. Radiol., (2009), 39 Suppl 1: S74-79, 1. [0134] Lonergan, G. J., Schwab, C. M., Suarez, E. S., and Carlson, C. L. Radiographics, (2002) 22(4), 911-934. [0135] Mairs, R. J. and Boyd, M., Nuc. Med. Bio., (2008) 35 Supp. 261: S9-20. [0136] Maris, J. M., Hogarty, M. D., Bagatell, R., and Cohn, S. L. Lancet, (2007), 369(9579), 2106-2120. [0137] Papaioannou, G., and McHugh, K. Cancer Imaging, (2005), 5, 116-127. [0138] Park, J. R., Eggert, A., and Caron, H. Pediatr. Clin. North Am., (2008), 55: 97-1 20, x. [0139] Rha, S. E., Byun, J. Y., Jung, S. E., Chun, H. J., Lee, H. G., and Lee, J. M. Radiographics, (2003), 23(1), 29-43. [0140] Robbins, E. R, Pediatr. Blood Cancer, (2008), 51: 453-457. [0141] Rufini, V., Calcagni, M. L., and Baum, R. P. Semin. Nucl. Med. (2006), 36(3), 228-247. [0142] Shirani, J. and Dilsizian, V. Curr. Opin. Biotechnol, (2007), 18, 65-72. [0143] Sisson, J. C., and Shulkin, B. L. Q. J. Nucl. Med., (1999), 43(3), 217-223. [0144] Vaidyanathan, G., Affleck, D. J., Alston, K. L., Welsh, P., and Zalutsky, M. R. (2004) Nucl. Med. Commun. 25(9), 947-955. [0145] Vaidyanathan, G., and Zalutsky, M. R., Bioconjug. Chem., (1992), 3(6), 499-503. [0146] Vaidyanathan, G., Q. J. Nucl. Med. Mol. Imaging, (2008), 52(4), 351-368. [0147] Vaidyanathan, G., Shankar, S., and Zalutsky, M. R. Bioconjug. Chem., (2001), 12(5), 786-797. [0148] Valk, T. W., Frager, M. S., Gross, M. D., Sisson, J. C., Wieland, D. M., Swanson, D. P., Mangner, T. J., and Beierwaltes, W. H. Ann. Intern. Med, (1981), 94(6), 762-767. [0149] Vik, T. A., Pfluger, T., Kadota, R., Castel, V., Tulchinsky, M., Farto, J. C., Heiba, S., Serafini, A., Tumeh, S., Khutoryansky, N., and Jacobson, A. F. Pediatr. Blood Cancer, (2009), 52(7), 784-790. [0150] Wafelman, A. R., Hoefnagel, C. A., Maes, R. A., and Beijnen, J. H., Eur. J. Nucl. Med. (1994), 21(6), 545-559. [0151] Wieland, D. M., Radiopharmaceuticals: Progress and Clinical Perspectives, (1986) 1, 117-153. [0152] Wieland, D. M., Wu, J., Brown, L. E., Mangner, T. J., Swanson, D. P., and Beierwaltes, W. H. J. Nucl. Med., (1980), 21(4), 349-353. [0153] Wong, F. C., and Kim, E. E. Eur. J. Radiol., (2009), 70(2), 205-211. [0154] Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
Multi-modal tumor imaging of neuroblastoma is essential for tumor staging, response evaluation and detection of relapsed diseased. The present invention provides a norepinephine analogue with a near-infrared (near-IR) dye, W765-BG, that efficiently and stably detects neuroblastoma in vivo using near-IR optical imaging. Confocal microscopy and optical imaging of neuroblastoma xenografts shows cell specific uptake and reveals exceptional tumor retention with a high tumor-to-tissue ratio up to 7 days after injection of W765-BG.
2
FIELD OF THE INVENTION [0001] The invention is in the field of light variation detection. The invention has application especially in the technical field of imaging. The invention relates more specifically to a device to detect, at a given moment, a light variation in front of the lens or in front of the flash window of a camera, and to warn the user of this variation. BACKGROUND OF THE INVENTION [0002] In the imaging field, the well-known problem of the photographer's finger placed in front of the camera lens at the moment of taking the shot has already been solved by various means. [0003] U.S. Pat. No. 3,878,548 describes mechanical means incorporated in a camera. These means enable, before exposure of the film, the prevention, by warning the photographer, of a finger from being placed in front of the objective. The means enable the shutter opening button to be locked, and enable the photographer to be warned visually, by moving a flag type element in the viewer. A disadvantage linked to these means relates to the relative movements of the various components (rods, springs, and pins) which can produce problems of operational reliability in use. The finger, placed in front of the lens, must touch by contact a mechanical element of the sliding shutter placed in front of the lens. Consequently, these means have the additional disadvantage that when a finger is placed in front of the lens, without touching the camera, this finger cannot operate the mechanical means of locking and warning. [0004] U.S. Pat. No. 4,866,470 describes a camera having a lens not projecting in relation to the front of the camera. This camera comprises tactile means of the type: projections, notches, specially profiled projections, and added to the surface of the lens. These tactile means are placed on the front of the camera, around the lens, to warn the photographer by touch, when their fingers get close to the lens. Besides the fact that the unwarned photographer does not necessarily know what these means are for, and besides the fact that they can be seen as not aesthetic or unpleasant, a disadvantage of such means is that if a finger is not placed pressing on the surface of the front of the camera, but is placed for example slightly set off from this surface, the photographer is not warned that their finger is in the field of the lens. [0005] U.S. Pat. No. 5,210,560 describes a camera that comprises photosensitive sensors placed near the lens or near the flash emission window. These sensors comprise emission and detection means, for example infrared, to emit light radiation in the direction of a photographer's finger that might, inadvertently, be positioned near the lens or flash. The sensors also comprise means to detect the reflection of the light radiation by the finger. Means of warning, for example of the electroluminescent diode (LED) type, are connected to the photosensitive sensors, so as to warn the photographer, if for example one of their fingers is badly placed in relation to the lens. These means imply that the detected finger passes just over the location of the photosensitive sensor. They do not guarantee an absolute detection in every case, according to the way the camera is held. That is to say that a finger positioned for example opposite the detector, this in relation to the lens, cannot be detected, because this finger is placed simply a little bit too far from the detector, while this finger nevertheless blocks the lens. [0006] U.S. Pat. No. 5,943,516 describes a camera provided with capacitive detectors or current detectors. These detectors enable, for example when a photographer's finger is badly positioned in front of a camera window, like the flash window, an electric parameter change to be generated by means of an electric circuit linked to the detection elements. This enables a visual alert (LED) or sound to be activated, which warns the photographer that one of their fingers is blocking the window. The alert device works from finger contact on a detector; and the device has the disadvantage of not working if the finger is placed for example in front of the window, without touching it. [0007] U.S. Pat. No. 6,351,606 describes an electronic or digital camera and a method to detect the obstruction, for example by a photographer's finger, of the window of the camera's electronic flash. The described means determine, after a shot using the electronic flash, the signal levels of the image pixels data, and then calculate whether the sensor CCD (Charge Coupled Device), connected to a signal level determination unit, is under-exposed. If it is determined that the electronic flash does not fully emit the quantity of light, then a processor concludes that a finger is blocking the flash window. In this case, an alert displays this obstruction, so as to prevent the emission of the flash. The problem of the failed picture, when a finger is placed in front of the lens during the shot, is experienced in an even more damaging way by the user of a silver process camera enabling a film to be exposed, because the anomaly will generally only be found after the development operation. This problem is not taken into account in U.S. Pat. No. 6,351,606. [0008] US Patent Application 2003/0012570 describes a camera that is provided with electromechanical means enabling the presence of a photographer's finger in front of the shutter to be detected. These means detect the presence of the finger from the moment when the finger touches a shutter lens. In particular they comprise electrodes and an oscillator to enable the phase differences of high frequency pulses, caused by a capacitance change of the electrodes, to be detected. These electromechanical means are of a limited efficiency, because the photographer's finger has to touch for example the shutter lens to generate a capacitance change. If the finger is simply placed in front of the lens, without touching the shutter lens, the electromechanical detection means do not work. SUMMARY OF THE INVENTION [0009] Invention finds its application in particular for recording devices, of the type for example still camera or moving picture camera. The invention relates to the means to calculate, at a given moment, a light difference between two light detection elements placed on the camera body. The aim of the invention is to eliminate the above-mentioned disadvantages of the previous art, which describe means that do not enable, due to their design or due to their location on a camera, the presence of an obstacle, for example a photographer's finger, placed in front of or in the field of the camera lens to be systematically reliably detected. The lack of reliability of the means of the previous art is due to the fact that if a finger is placed in the shot field and does not touch (in a tactile way) the camera lens, or if the finger is placed a little bit too far from the detection means, then it is not recognized by these detection means. [0010] It is also an aim of the invention to prevent expensive and qualitatively unsatisfactory operations for the photographer. These operations result from the taking of one or more photographic shots that will for example show a finger on the photographic paper after development, or an underexposure of the film if a finger is placed in front of the flash, in the case of a flash camera. Very often, for example on a camera, a viewer and separate lens are found. Furthermore, camera sizes are increasingly compact; consequently, the problem of the finger placed in front of the lens should be taken into account reliably, in particular when the photographer holds the camera vertically: it is in this position (taking vertical photos), with a modest sized camera, that the risks of placing a finger in front of the lens are greater. In other words, the problem of the finger placed in the shooting field is accentuated with the camera held vertically to take high direction shots. On the other hand, camera ergonomics and dimensions are normally planned for holding this camera in a horizontal position. Now, these two camera positions, horizontal or vertical, for the same photographer, generally generate different finger positions when holding the camera; and these finger positions in relation to the camera are generally mastered less well, when the photographer holds the camera in a vertical position. [0011] Consequently, and contrary to the means of the previous art, the invention enables a better response to the problem of a finger placed for example in front of the camera lens, by systematically detecting any unusual presence of one (or more) objects placed anywhere in a camera's shooting field, and this whether or not this object touches the camera. [0012] It is an aim of the invention to be able to be used in any type of still camera or motion-picture camera, independently of the geometry of the camera body, invention can be for example incorporated into a camera provided with a projecting lens or into a camera having a non-projecting lens. The invention thus has the advantage of being able to be incorporated easily into any camera, without any particular locating restrictions. [0013] The aim of the invention is therefore to increase the detection reliability of the presence of an object, for example a finger, in front of a camera lens, independently of the position (horizontal or vertical) in which the photographer holds the camera, during a shot, and whatever the shape of the camera body. The detection reliability of an object, in relation to the previous art, is greater, whatever the relative position of the object in front of the lens. In other words, whether this object is for example in contact with the camera or whether it does not touch the camera, the invention device enables the photographer to be warned before taking the shot. [0014] It is also an aim of the invention not to use mechanical elements, because the movements of these elements, located inside and/or outside the camera body, risk producing operating noises, or risk generating malfunction risks, of the locking or jamming type, that compromise reliability. [0015] The invention device enables the above-mentioned disadvantages to be eliminated. The object of the invention is a camera comprising a device with at least two light detection elements. These light detection elements are connected to a threshold comparison means, and a warning device controlled by the comparison means emits a warning, if, at a given moment, a light difference between two light detection elements exceeds a set value. [0016] The light detection element comprises at least one light measuring cell. [0017] The light measuring cell comprises a capacitance element, a resistance element, a photodiode, an amplifier and an output. The cell enables a quantity of light received by this cell to be transformed into an electric parameter, in the output of said cell. [0018] In a first embodiment of the invention, the camera also comprises a summing means connected between the light measuring cell and the threshold comparison means. [0019] The threshold comparison means is for example a comparator with operational amplifier, or, in a variant, the threshold comparison means comprises a comparator connected to a computer. [0020] In a second embodiment of the invention, the threshold comparison means comprises a multiplexing unit connected to an analog-to-digital converter, and to a computer unit. Advantageously the computer unit is a microprocessor. [0021] The invention device comprises a warning device that is selected in the group comprising light, and/or sound, and/or mechanical warning devices. The warning device is for example one or more electroluminescent diodes placed inside the viewer. Or, the warning device is audible: for example a buzzer. [0022] The invention device is used advantageously with a camera comprising a lens, a viewer, and a flash. Each light detection element comprises at least one light measuring cell. In a preferred embodiment, the camera is characterized in that the first light detection element comprises two light measuring cells arranged around the viewer, the second light detection element comprises eight light measuring cells arranged around the lens, and the third light detection element comprises two light measuring cells arranged around the flash. The light measuring cells can be arranged regularly, respectively around the respective perimeters of the viewer, lens and flash. [0023] The invention device enables, at a given moment, light variation, for example between two different places arranged on a camera body, to be detected and then a difference corresponding to this variation to be calculated. These two locations are, for example, the zone corresponding to the viewer location, placed on the front of the camera body, and the zone corresponding to the lens location, also placed on the front of the camera. If an object, for example a finger or part of finger, is positioned in the field of the shooting lens, by touching or not touching this shooting lens, a light variation is detected, a difference is calculated, and a comparison of this differential with a set or reference value enables a visual and/or sound warning device to be activated to warn the photographer. The set value corresponds to a totally free shooting field, i.e. not blocked by the presence of an object disturbing the quantity of ambient light near the shooting lens. [0024] The light detection elements of the invention enable, at a given moment, for example just before the shot, on the one hand the ambient light around the viewer to be measured, and on the other hand, the ambient light around the lens or flash to be measured. And this, independently of whether the object (a finger), placed in the lens or flash field, touches or not these light detection elements. The device of the present invention also has the advantage of being able to detect the location, on the camera, where the disturbing object is: for example, in front of the lens, and/or the flash. [0025] Other characteristics and advantages of the invention will appear on reading the following description of the embodiments, with reference to the drawings of the various figures. BRIEF DESCRIPTION OF THE DRAWINGS [0026] FIG. 1 schematically represents a first embodiment of the device according to the invention. [0027] FIG. 2 schematically represents a second embodiment of the device according to the invention. [0028] FIG. 3 schematically represents a third embodiment of the device according to the invention. [0029] FIG. 4 schematically represents a light detection cell of a light detection element according to the invention. [0030] FIG. 5 schematically represents the front of a camera according to the invention. DETAILED DESCRIPTION OF THE INVENTION [0031] The invention is described with reference to preferred embodiments. [0032] The following description is a detailed description of the main embodiments of the invention, with reference to the drawings in which the same numerical references identify the same elements in each of the figures. [0033] The invention device is intended to be located for example on a camera. The front of the body 23 of this camera comprises, according to FIG. 5 , a viewer 20 , a shooting lens 22 , and a flash 21 as an option. [0034] FIG. 1 corresponds to a first embodiment of the invention device, intended to be located for example on a camera not comprising flash. The invention device comprises a first light detection element 1 . This first element 1 comprises a set of light measuring cells 1 C, independent one from another. These light measuring cells are independent, i.e. they operate by producing, independently one from another, the electrical parameters data that is specific to them. The light measuring cells 1 C are placed for example on the front of the body 23 : they are preferably arranged regularly around the viewer 20 . The invention device also comprises a second light detection element 2 comprising a set of light measuring cells 2 C independent one from another. According to FIG. 5 , these light measuring cells 2 C are placed for example on the front of the body 23 , and are preferably arranged regularly around the lens 22 . The elements constituting the light measuring cells 2 C are advantageously identical to the elements constituting the light measuring cells 1 C. In another embodiment, the light measuring cells 1 C, 2 C may not be arranged regularly around these perimeters. [0035] FIG. 2 corresponds to a second embodiment of the invention device, intended to be located for example on a camera whose body front 23 comprises, according to FIG. 5 , besides the viewer 20 and the lens 22 , a flash 21 . The device according to this second embodiment comprises a third light detection element 3 . This third light detection element 3 comprises a set of light measuring cells 3 C, independent one from another, placed for example on the front of the body 23 , and preferably arranged equally around the flash 21 . The elements constituting the light measuring cells 3 C are advantageously identical to the elements constituting the light measuring cells 1 C and 2 C. [0036] According to a preferred embodiment of the invention, and according to FIGS. 2 and 5 , the first light detection element 1 comprises two light measuring cells 1 C, placed and arranged regularly or uniformly around the perimeter of the viewer 20 . The second light detection element 2 , comprises eight light measuring cells 2 C, placed and arranged regularly around the perimeter of the shooting lens 22 , and the third light detection element 3 comprises two light measuring cells 3 C, placed and arranged regularly around the perimeter of the flash 21 . If the lens 22 has for example a circular shape, eight light measuring cells 2 C are arranged regularly around the perimeter of this lens, this means that two consecutive cells form together, according to FIG. 5 , an angle a of 45 degrees. In another embodiment, the light measuring cells 1 C, 2 C, 3 C may not be arranged regularly around these perimeters. [0037] Besides the previously described embodiments, the camera can take, in general, light detection elements ( 1 , 2 , 3 ) each comprising at least one light measuring cell ( 1 C, 2 C, 3 C). [0038] According to FIG. 4 , each light measuring cell 1 C, 2 C, 3 C preferably comprises a capacitance element 14 , a resistance element 15 , an output 16 , a photodiode 17 , and an amplifier 18 referenced to the ground 19 . The function of the photodiode 17 is to transform incident light radiation, for example due to the ambient light, received by this cell, into an electric current, and which thus becomes an analog value, the voltage at the output 16 of the light measuring cell 1 C, 2 C, 3 C. Consequently, a variation of this incident light on the photodiode 17 generates a variation of output current 16 . For each of the light measuring cells 1 C, 2 C, 3 C belonging to the same light detection element 1 , 2 , 3 , the gains of the amplifiers 18 are identical. Because of the capacitance 14 , the amplifier 18 is also a low-pass filter, for example having a cutoff frequency of 10 Hertz. This frequency of 10 Hertz is chosen to avoid, if necessary, the influence of lighting lamps surrounding the invention device. The resistance 15 enables the conversion gain of the current flowing in the photodiode 17 to be adjusted in voltage. [0039] According to the embodiments of FIGS. 1 and 2 , each of the light measuring cells 1 C, 2 C, 3 C is connected to a summing means 3 S, 4 , 5 . In a first embodiment of the invention, according to FIGS. 1 and 2 , this summing means is connected to a threshold comparison means 8 . The threshold comparison means 8 is, for example, a comparator with operational amplifier. But, according to FIGS. 1 and 2 , this threshold comparison means 8 can also be a comparator 7 , connected to a computer 6 . In a variant, the summing means 3 S, 4 , 5 are incorporated into the computer 6 or the comparison means 8 . According to FIGS. 1 and 2 , the threshold comparison means 8 enables analog processing to be performed of the electrical parameters values (voltage) transmitted to the outputs 16 of the light measuring cells 1 C, 2 C, 3 C. In other words, the comparison means 8 enables algebraic operations among the values of the electrical parameters to be executed automatically. The comparison means 8 thus enables the values of the voltage induced respectively at the outputs 16 of each light measuring cell 1 C, 2 C, 3 C of the light detection elements 1 , 2 , 3 to be added automatically to obtain a sum Vi, respectively at points 24 , 25 , 26 . Every light detection element 1 , 2 , 3 induces a sum Vi specific to said element. The index “i” is an integer that varies for example from 1 to 2 for the embodiments of FIGS. 1 and 3 , which comprise two light detection elements 1 and 2 . The index “i” varies for example from 1 to 3 for the embodiment of FIGS. 2 , which comprises three light detection elements 1 , 2 , 3 . The threshold comparison means 8 also enables to automatically subtract from them, the respective sums Vi thus obtained at points 24 , 25 , 26 . These sums Vi correspond respectively to each of the electrical parameters values, and the sums Vi are specific to each of the light detection elements 1 , 2 , 3 . For a given light detection element, Vi represents the sum of the individual analog values produced at the outputs 16 of the light measuring cells 1 C, 2 C, 3 C. In this embodiment, the unit for measuring the electrical parameters is the “volt”. If the elements 14 , 15 , 17 , 18 which form the light measuring cells 1 C, 2 C, 3 C are not identical among the various cells, the device is adjusted, so that the sum of the respective voltages Vi, measured at points 24 , 25 , 26 , is the same at these three points 24 , 25 , 26 . This adjustment is operated when there is no object disturbing the incident ambient light on the set of light detection elements 1 , 2 , 3 . [0040] The threshold comparison means 8 is connected to a warning device 9 . This warning device 9 is visual and/or audible. The warning device 9 can be activated visually and/or audibly by the comparison means 8 . In a preferred embodiment of the invention, the warning device 9 comprises, for example, one or more electroluminescent diodes (LED) that are placed in the viewer window, so as to be visible to the photographer's eye, when the latter prepares to take a photograph. But the warning device 9 can also be an audible element, for example a buzzer incorporated into the camera. This buzzer can, for example, be connected to the LEDs 9 , to operate (to be activated) simultaneously with the LEDs 9 , or not connected to said LEDs, and to operate independently of them. [0041] In a second embodiment of the invention, according to FIG. 3 , the threshold comparison means 8 comprises a multiplexing unit 10 connected to an analog-to-digital converter 11 to communicate, via a data transport element 12 , with a computer unit 13 . The multiplexing unit 10 is connected to the outputs 16 of the light measuring cells 1 C, 2 C, 3 C, and enables the individual values of the electrical parameters at each of these outputs 16 to be collected. The summing means of the output data of the light measuring cells 1 C, 2 C, 3 C can be integrated either into the multiplexing unit 10 , or into the computer unit 13 . The data transport element 12 is for example a bus connected between on the one hand the multiplexer 10 —converter 11 assembly, and the computer unit 13 on the other hand. The computer unit 13 is, for example, a microprocessor. According to the embodiment of FIG. 3 , the comparison means 8 enables a conversion of the voltage analog data to be made into digital values. The comparison means 8 of the embodiment of FIG. 3 thus enables digital processing of the voltage parameter values Vi produced at points 24 , 25 , 26 to be performed. The voltage parameters Vi come from the summed individual data, previously produced at the outputs 16 of the light measuring cells 1 C, 2 C, 3 C. In other words, the comparison means 8 enables algebraic operations among the analog data to be executed automatically after they have been converted into digital values. The comparison means 8 enables, like in the previously described embodiments, individual values specific to each light measuring cell (outputs 16 ) to be added to obtain the summed values Vi, and to subtract from them the summed values Vi specific to each light detection element 1 , 2 , 3 . [0042] If there is no object in front of the viewer 20 , lens 22 , or flash 21 , the accumulated voltage Vi at the outputs 16 of the light measuring cells 1 C, 2 C, 3 C is for example, according to FIGS. 1 and 2 , equal to a value V 1 at points 24 , 25 , 26 : the case where it is considered, for example, that the ambient lighting is the same in front of each light measuring cell. This value V 1 is for example obtained by choosing an appropriate resistance value 15 in each light measuring cell, and this for each light detection element 1 , 2 , 3 . Consequently, if there is no object blocking the ambient light radiation on the viewer 20 , lens 22 , and flash 21 , the difference of the accumulated voltages Vi between the first light detection element 1 of the viewer and the other light detection elements 2 , 3 is zero. [0043] The fact that an object is positioned in front of the viewer 20 , is not of much practical interest on a camera with a viewer. In this case, if for example the photographer's finger is placed in front of the viewer 20 , the photographer will realize it visually, by looking through the viewer, just before taking a photograph. According to FIG. 2 , the invention device enables, by using for example the specific calculation units 6 A and 6 B of the computer 6 , to calculate the difference between the electrical parameter values (accumulated voltages Vi) between the first light detection element 1 corresponding to the viewer 20 serving as reference, and respectively the second light detection elements 2 and 3 , corresponding to the lens 22 and flash 21 . The values Vi, as previously described, are measured at points 24 , 25 , 26 . [0044] If an object is present, either in front of the flash 21 , or the lens 22 , the accumulated voltage of the outputs 16 of the cells of the light detection element corresponding to the flash or the lens takes for example a value V 2 , different than V 1 (no object). According to FIG. 2 , if the object blocks for example the lens 22 , the corresponding light detection element 2 produces a voltage V 2 at the point 25 ; the voltages at points 24 (viewer) and 26 (flash) remaining equal to V 1 (no object). Thus, the object creates an imbalance in the relations between the voltages of each light detection element 1 , 2 , 3 . The difference of the voltages (V 1 −V 2 ) is thus different than zero. There is a light difference between the light detection elements 2 (lens) on the one hand, and 1 (viewer), 3 (flash) on the other hand. [0045] The threshold comparison means 8 enables the presence of an object present in front of the flash 21 and lens 22 windows to be detected. When an object (generally a finger tip) is positioned for example in front of the second light detection elements 2 and 3 , corresponding to the light measurement, respectively in front of the lens 22 and the flash 21 , i.e. there is, for example, at the same moment an object (e.g. photographer's finger) placed in front of the lens 22 and also another object (e.g. another finger of the photographer) placed in front of the flash 21 , the threshold comparison means 8 determines a difference between the summed value of the first electrical parameter V 1 , and respectively the summed values of the other electrical parameters V 2 and V 3 . This difference is produced by the calculations of the differences (V 1 −V 2 ) on the one hand, and (V 1 −V 3 ) on the other hand. The first value V 1 corresponds to the measurement of the light near the viewer 20 ; V 1 corresponds for example to the ambient light near the viewer 20 . The values V 2 , V 3 correspond, for example, to the measurement of ambient light attenuated near the lens 22 and the flash 21 . V 2 differs from V 3 in so far as, for example, the attenuated light on the lens 22 , in relation to the ambient light, is a little more or less than on the flash 21 . In other words, the quantity of incident light on the lens 22 is, at a given moment, different than the quantity of incident light on the flash 21 . In this example, the value V 1 corresponds to a set or reference value Vr, for which there is no object in front of the light detection element 1 of the viewer 20 . The preferably chosen set or reference value Vr is “zero” (Vr=0=V 1 −V 1 ). When an object is positioned in front of another light detection element 2 , 3 , i.e. an object is placed for example in front of the lens 22 , and this object or another object is also placed in front of the flash 21 , the comparison means 8 determines a positive or negative difference between the value of the first parameter V 1 and the values of the parameters V 2 , V 3 . This difference, different than zero (Vr=zero=set or reference value), expresses the existence of a light difference between the zones 20 and 22 on the one hand, and between the zones 20 and 21 on the other hand; the zone 20 being chosen as a reference zone. The sign of this difference 37 plus” or “minus”) is a function of the internal arrangement of the electrical circuit components of the comparison means 8 . In a preferred embodiment, and to calculate a positive difference, the programming of the comparison means 8 integrates the absolute value of the difference calculated between V 1 and V 2 , or between V 1 and V 3 . The formula of the difference is thus |V 1 −V 2 | or |V 1 −V 3 |. [0046] The invention device also enables the location to be detected, for example on the camera, where the disturbing object is placed that cannot be seen by the photographer whose eye is placed in the viewer. Thus the invention device enables, for example, the detection of an object placed in front of the shooting lens 22 : generally the most harmful case, in terms of the final result sought by the photographer. In this first case, the absolute value |V 1 −V 2 | is different than zero. The invention device also enables, for example, the detection of an object placed in front of the flash 21 : not a systematically harmful case because, according to the ambient light conditions, the use of flash is not always required. In this second case, the absolute value |V 1 −V 3 | is different than zero. [0047] The invention device also enables the detection of an object placed for example both in front of the shooting lens 22 and in front of the flash 21 . In this latter case, the values |V 1 −V 2 | and |V 1 −V 3 | are different than zero. [0048] Detection of the object in front of the flash 21 and/or the lens 22 is operated by a warning device 9 , connected to the comparison means 8 . The warning device 9 comprises for example at least one electroluminescent diode placed inside the viewer 20 , so as to be visible by the photographer, when they look through the viewer 20 . In a preferred embodiment of the invention, two electroluminescent diodes (LEDs) are placed in the viewer 20 . On the one hand, a first diode producing for example red light, if an object is placed in front of the lens 22 ; on the other hand, a second diode producing orange light, if an object is placed in front of the flash 21 . But the warning device 9 can also be an audible element, buzzer type, placed for example on the front 23 of the camera. It can also be planned for this buzzer to be activated in a synchronized way (i.e. operates at the same time) with the electroluminescent diodes 9 . [0049] If |V 1 −V 3 | is different than zero and no object is blocking the viewer 20 , this means that an object is placed in front of the flash window 21 . In the embodiment of the invention with flash, the comparison means 8 also enables the saving of a “flash threshold” value Vf. This value Vf corresponds to the ambient light level, around the camera, below which the flash must be put into service, otherwise the photograph is underexposed. The comparison means 8 enables the values Vf and the reference value to be compared with the ambient light, which is for example V 1 in this example. If the difference between Vf and V 1 is different than zero (zero is the set value Vr), and that for example Vf is greater than V 1 , then the flash warning device 9 is not activated: in this case, the flash is not used, because it is not considered necessary to obtain a correct photograph. The flash warning device 9 is for example the orange LED. [0050] In the opposite case, where for example Vf is less than V 1 , the flash's orange LED is activated. This last case means on the one hand that the camera's flash, for example automatic, is required to obtain a correct photograph, given the level of ambient light, and that, on the other hand an object blocks the flash. The LED 9 thus warns for example the photographer that they should remove their finger that is blocking the flash 21 . [0051] In special case where the photographer's finger partially blocks for example the viewer 20 , and if the photographer deliberately chooses to leave their finger in front of the viewer 20 , an imbalance between the accumulated voltages Vi of each light detection element 1 , 2 , 3 occurs. And this imbalance occurs, whether the lens 22 and/or flash 21 are blocked or not by an object themselves. In this case, the comparison means 8 records the differences, between voltages Vi, different than zero, and the warning device 9 is activated.
The invention relates to a device for detecting, at a given moment, a light difference between two light detection elements. The invention has application in the technical field of imaging, and more particularly in cameras comprising the invention device. The invention describes a device for detecting a light variation between two locations ( 20, 21, 22 ) placed on one surface of a camera body ( 23 ) and calculating a corresponding difference. The camera comprises light measuring cells ( 1 C, 2 C, 3 C) arranged regularly around the viewer ( 20 ), the flash ( 21 ), and the lens ( 22 ). A light differential existing between two locations, for example between the viewer ( 20 ) and the lens ( 22 ), automatically generates a calculation of this light difference, to compare it with a set or reference value (Vr). A warning device linked to the invention device is activated if the light difference exceeds the set value (Vr).
6
RELATED APPLICATIONS This patent document is a continuation of U.S. application Ser. No. 13/745,995, filed Jan. 21, 2013, now U.S. Pat. No. 8,703,256, which is a continuation of U.S. application Ser. No. 12/875,445, filed Sep. 3, 2010, now U.S. Pat. No. 8,361,574, which is a continuation of U.S. application Ser. No. 10/911,249, filed Aug. 4, 2004, now U.S. Pat. No. 7,824,748, which is a divisional of U.S. application Ser. No. 09/541,845, filed Apr. 3, 2000, now U.S. Pat. No. 6,884,311, which is a continuation-in-part of U.S. application Ser. No. 09/391,910, filed Sep. 9, 1999 and which has been reissued as U.S. application Ser. No. 12/218,260, filed Jul. 11, 2008, now U.S. Pat. No. RE41,623, the entirety of each of the disclosures of which are explicitly incorporated by reference herein. This patent document is also related to U.S. application Ser. No. 12/034,932, filed Feb. 21, 2008, now U.S. Pat. No. 7,771,554, U.S. application Ser. No. 12/193,578, filed Aug. 18, 2008, now U.S. Pat. No. 7,749,581, U.S. Ser. application No. 12/193,573, filed Aug. 18, 2008, now U.S. Pat. No. 7,754,042, and U.S. application Ser. No. 12/193,562, filed Aug. 18, 2008, now U.S. Pat. No. 7,766,475, the entirety of each of the disclosures of which are explicitly incorporated by reference herein. BACKGROUND The present invention relates to a method for transferring an image onto a colored base and to an article comprising a dark base and an image with a light background on the base. Image transfer to articles made from materials such as fabric, nylon, plastics and the like has increased in popularity over the past decade due to innovations in image development. On Feb. 5, 1974, LaPerre et al. had issued a United States Patent describing a transfer sheet material markable with uniform indicia and applicable to book covers. The sheet material included adhered plies of an ink receptive printable layer and a solvent free, heat activatable adhesive layer. The adhesive layer was somewhat tacky prior to heat activation to facilitate positioning of a composite sheet material on a substrate which was to be bonded. The printable layer had a thickness of 10-500 microns and had an exposed porous surface of thermal plastic polymeric material at least 10 microns thick. Indicia were applied to the printable layer with a conventional typewriter. A thin film of temperature-resistant low-surface-energy polymer, such as polytetrafluoroethylene, was laid over the printed surface and heated with an iron. Heating caused the polymer in the printable layer to fuse thereby sealing the indicia into the printable layer. On Sep. 23, 1980, Hare had issued U.S. Pat. No. 4,224,358, which described a kit for applying a colored emblem to a T-shirt. The kit comprised a transfer sheet which included the outline of a mirror image of a message. To utilize the kit, a user applied a colored crayon to the transfer sheet and positioned the transfer sheet on a T-shirt. A heated instrument was applied to the reverse side of the transfer sheet in order to transfer the colored message. The Greenman et al. patent, U.S. Pat. No. 4,235,657, issuing Nov. 25, 1980, described a transfer web for a hot melt transfer of graphic patterns onto natural, synthetic fabrics. The transfer web included a flexible substrate coating with a first polymer film layer and a second polymer film layer. The first polymer film layer was made with a vinyl resin and a polyethylene wax which were blended together in a solvent or liquid solution. The first film layer served as a releasable or separable layer during heat transfer. The second polymeric film layer was an ionomer in an aqueous dispersion. An ink composition was applied to a top surface of the second film layer. Application of heat released the first film layer from the substrate while activating the adhesive property of the second film layer thereby transferring the printed pattern and a major part of the first layer along with the second film layer onto the work piece. The second film layer bonded the printed pattern to the work piece while serving as a protective layer for the pattern. DeSanders et al. patent, U.S. Pat. No. 4,399,209, issuing Aug. 16, 1983, describes an imaging system in which images were formed by exposing a photosensitive encapsulate to actinic radiation and rupturing the capsules in the presence of a developer so that there was a pattern reaction of a chromogenic material present in the encapsulate or co-deposited on a support with the encapsulate and the developer which yielded an image. The Joffi patent, U.S. Pat. No. 4,880,678, issuing Nov. 14, 1989, describes a dry transfer sheet which comprises a colored film adhering to a backing sheet with an interposition of a layer of release varnish. The colored film included 30%-40% pigment, 1%-4% of cycloaliphatic epoxy resin, from 15%-35% of vinyl copolymer and from 1%-4% of polyethylene wax. This particular printing process was described as being suitable for transferring an image to a panel of wood. The Kronzer et al. patent, U.S. Pat. No. 5,271,990, issuing Dec. 21, 1993, describes an image-receptive heat transfer paper that included a flexible paper web based sheet and an image-receptive melt transfer film that overlaid the top surface of the base sheet. The image-receptive melt transfer film was comprised of a thermal plastic polymer melting at a temperature within a range of 65°-180° C. The Higashiyami et al. patent, U.S. Pat. No. 5,019,475, issuing May 28, 1991, describes a recording medium that included a base sheet, a thermoplastic resin layer formed on at least one side of the base sheet and a color developer formed on a thermoplastic resin layer and capable of color development by reaction with a dye precursor. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a schematic view of one process of image transfer onto a colored product, of the present invention. FIG. 2 is a schematic view of one prior art process of image transfer onto a colored product. FIG. 3 a is a cross-sectional view of one embodiment of the image transfer device of the present invention. FIG. 3 b is a cross-sectional view of another embodiment of the image transfer device of the present invention. FIG. 4 is a cross-sectional view of another embodiment of the image transfer device of the present invention. FIG. 5 is a cross-sectional view of one other embodiment of the image transfer device of the present invention. FIG. 6 is a cross-sectional view of another embodiment of the image transfer device of the present invention. FIG. 7 is a cross-sectional view of another embodiment of the image transfer device of the present invention. FIG. 8 is a cross-sectional schematic view of one process of image transfer onto a colored product, of the present invention. SUMMARY One embodiment of the present invention includes a method for transferring an image to a colored substrate. The method comprises providing an image transfer sheet comprising a release layer and an image-imparting layer that comprises a polymer. The image-imparting layer comprises titanium oxide or another white pigment or luminescent pigment. The image transfer sheet is contacted to the colored substrate. Heat is applied to the image transfer sheet so that an image is transferred from the image transfer sheet to the colored substrate. The image transferred comprises a substantially white or luminescent background and indicia. Another embodiment of the present invention includes an image transfer sheet. The image transfer sheet comprises a polymer. The polymer comprises titanium oxide or other white pigment or luminescent pigment. One other embodiment of the present invention includes a method for making an image transfer sheet. The method comprises providing an ink receptive polymer and impregnating the polymer with titanium oxide or other white pigment or luminescent pigment. An image is imparted to the polymer. DETAILED DESCRIPTION One method embodiment of the present invention, for transferring an image onto a colored base material, illustrated generally at 100 in FIG. 1 , comprises providing the colored base material 102 , such as a colored textile, and providing an image 104 that comprises a substantially white background 106 with indicia 108 disposed on the substantially white background, applying the image 104 to the colored base 102 with heat to make an article, such as is shown generally at 110 in FIG. 1 with the substantially white background 106 , the image 108 disposed on the white background, so that the image and background are adhered to the colored base in a single step. As used herein, the term “base” or substrate refers to an article that receives an image of the image transfer device of the present invention. The base includes woven or fabric-based materials. The base includes articles of clothing such as T-shirts, as well as towels, curtains, and other fabric-based or woven articles. As used herein, the term “indicia” refers to an image disposed on the image transfer device of the present invention in conjunction with a substantially white background. Indicia include letters, figures, photo-derived images and video-derived images. As used herein, the term “white layer” refers to a layer on a transfer sheet positioned between a release layer and a receiving layer. The white layer imparts a white background on a dark substrate. The method of the present invention is a significant improvement over conventional two-step image transfer processes. One prior art embodiment is shown generally at 200 in FIG. 2 . Typically in prior art embodiments, a colored base, in particular, a dark base such as a black T-shirt 202 , is imparted with an image in a multiple step process. One prior art method 200 includes applying a white or light background 204 to the colored base 202 with heat. The light or white background 204 is typically a polymeric material such as a cycloaliphatic epoxy resin, a vinyl copolymer and/or a polyethylene wax. A sheet 206 with an image 208 printed or otherwise imparted is applied to the substantially white polymeric material 204 by aligning the image to the white background and applying heat. This two-step prior art process requires the use of two separate sheets 204 and 206 , separately applied to the colored base. The two-step prior art process 200 also requires careful alignment of the image 208 to the white background 202 . Consequently, the two-step process is exceedingly time-consuming and, because of improper alignment, produces significant wastage of base and image transfer materials. With the method of the present invention, a sheet such as is shown at 104 a , is prepared having a substrate layer 302 that comprises a polymeric material such as polypropylene, paper, a polyester film, or other film or films having a matte or glossy finish, such as is shown in FIG. 3 a . The substrate layer 302 may be coated with clay on one side or both sides. The substrate layer may be resin coated or may be free of coating if the substrate is smooth enough. The resin coating acts as a release coating 304 . The coating weight typically ranges from 40 g/square meter to 250 g/square meter. In one embodiment, the range is 60 to 130 g/square meter. In one embodiment, overlaying the substrate 302 or base paper is a silicone coating 304 . Other release coatings such as fluorocarbon, urethane, or acrylic base polymer are usable in the image transfer device of the present invention. One other release coating is a silicone coating. The silicone coating has a release value of about 10 to 2500 g/inch, using a Tesa Tape 7375 tmi, 90 degree angle, 1 inch tape, 12 inches per minute. These other release coatings are, for some embodiments, impregnated with titanium oxide or other white pigments in a concentration of about 20% by weight. Impregnated within the substrate 302 , shown in FIG. 3 a and/or silicone coating 304 , shown in FIG. 3 b , is a plurality of titanium oxide particles or other white pigment or luminescent pigment in a concentration that may be as high as about 35% by volume or as low as 5% by volume. Specific embodiments include titanium oxide concentrations or talc, or barium or aluminum hydrate with or without calcium carbonate or aluminum silicate in a range from 0 to 50%, by weight. Other materials such as hollow pigment, kaolin, silica, zinc oxide, alumina, zinc sulfate, calcium carbonate, barium or aluminum oxide; aluminum trihydrate, aluminum fillers, aluminum silicate, alumina trihydrate, barium sulfate, barium titanate, fumed silica, talc, and titanium oxide extenders are also usable in conjunction with titanium oxide or instead of titanium oxide. It is believed that any white organic or inorganic pigment that has a concentration at a level of 0 to 7% by weight total ash content is acceptable for use. In one embodiment illustrated at 600 in FIG. 6 , a white layer 606 includes a concentration of blended pigments or other pigments at a concentration of 10 to 40% by weight. Other pigments such as Lumilux®, manufactured by Reidel de Haen Aktiengellschaft of Germany, or other luminescent pigments, such as pigments manufactured by Matsui International, Inc., may be used in the method and article of the present invention. The titanium oxide or other white pigment or luminescent particles impart to the substrate layer, a substantially white background with a glowing that occurs at night or in the dark area. The pigments are used in conjunction with ink jet printing, laser printing, painting, other inks, for “Glow in the Dark” images, for light resolution displays, for pop displays, monochrome displays or image transfer articles. Suitable pigments are excitable by daylight or artificial radiation, fluorescent light, fluorescent radiation, infrared light, infrared radiation, IR light, ultra-violet light or UV radiation. Other materials may be added to the substrate such as antistatic agents, slip agents, lubricants or other conventional additives. The white layer or layers are formed by extrusion or co-extrusion emulsion coating or solvent coating. The white layer coating thickness ranges from 0.5 to 7 mils. In one embodiment, the range is 1.5 to 3.5 mils or 14 g/meter squared to up to 200 g/meter squared. In other embodiments of the image transfer sheet, a changeable color was added to one or more of the layers of the image transfer sheet. The color-changeable material transferred utilized a material such as a temperature sensitive pigmented chemical or light changeable material, a neon light which glows in the dark for over 50 hours and was a phosphorescent pigment, a zinc-oxide pigment or a light-sensitive colorant. A concentrated batch of one or more of the materials of polyethylene, polyester, EVA, EAA, polystyrene, polyamide or MEAA which was a Nucrel-like material was prepared. The color-changeable material was added to the layer material up to a concentration of 100% by weight with 50% by weight being typical. The color-changeable material technologies changed the image transfer sheet from colorless to one or more of yellow, orange, red, rose, red, violet, magenta, black, brown, mustard, taupe, green or blue. The color-changeable material changed the image transfer sheet color from yellow to green or from pink to purple. In particular, sunlight or UV light induced the color change. The color-changeable material was blendable in a batch process with materials such as EAA, EVA, polyamide and other types of resin. The polymer was extruded to 0.5 mils or 14 g/m 2 to 7 mils or 196 g/m 2 against a release side or a smooth side for a hot peel with up to 50% by weight of the color-changeable concentrate. The first ink-receiving layer 306 was an acrylic or SBR EVA, PVOH, polyurethane, MEAA, polyamide, PVP, or an emulsion of EAA, EVA or a blend of EAA or acrylic or polyurethane or polyamide, modified acrylic resins with non-acrylic monomers such as acrylonitrile, butadiene and/or styrene with or without pigments such as polyamide particle, silica, COCl 3 , titanium oxide, clay and so forth. The thermoplastic copolymer was an ethylene acrylic acid or ethylene vinyl acetate grade, water- or solvent-based, which was produced by high pressure copolymerization of ethylene and acrylic acid or vinyl acetate. Use of EAA or EVA as a binder was performed by additionally adding in a concentration of up to 90% with the concentration being up to 73% for some embodiments. The titanium oxide pigment concentration was, for some embodiments, about 50%. The photopia concentration was about 80% maximum. The additive was about 70% maximum. The second receiving layer 306 included the photopia or color changeable material in a concentration of up to 70% by weight with a range of 2 to 50% by weight for some embodiments. PHOTOPHOPIA is an ink produced by Matsui Shikiso chemical, Co. of Kyoto, Japan. The pigment ranged from 0 to 90% and the binder from 0 to 80%. This type of coloring scheme was used in shirts with invisible patterns and slogans. The PHOTOPIA products were obtained from Matsui International Company, Inc. While they have been described as being incorporated in the ink-receiving layer, the PHOTOPIA products were also applicable as a separate monolayer. PHOTOPIA-containing layers were coated onto the release layer by conventional coating methods such as by rod, slot, reverse or reverse gravure, air knife, knife-over and so forth. Temperature sensitive color changeable materials could also be added to the image transfer sheet. Chromacolor materials changed color in response to a temperature change. The Chromacolor solid material had a first color at a first temperature and changed color as the temperature changed. For instance, solid colors on a T-shirt became colorless as a hot item or the outside temperature increased. Chromacolor was prepared as a polypropylene concentrate, polyethylene, polystyrene, acrylo-styrene (AS) resins, PVC/plasticizer, nylon or 12 nylon resin, polyester resin, and EVA resin. The base material for this image transfer sheet embodiment was selected from materials such as paper, PVC, polyester, and polyester film. This type of image transfer sheet was fabricated, in some embodiments, without ink-jet receiving layers. It was usable by itself for color copy, laser printers, and so forth and then was transferable directly onto T-shirts or fabrics. In one or both receiving layers 306 , permanent color was addable with a color-changeable dispersion when the temperature changed, that is, when color disappeared. The color returned to permanent color as was shown in previous examples. With this formulation, the changeable color was added to one or more layers in a concentration of up to about 80% by weight with a range of 2-50% by weight being typical. The base paper for this embodiment was about 90 g/m 2 . About 0.5 mils EAA were applied with 10% PHOTOPIA or temperature-sensitive color-changeable materials. The top coat layer was an ink-receiving layer that contained polyamides, silica, COCl 3 for 15% color-changeable items. For some embodiments, a white layer 506 , 606 , such as is shown in FIGS. 5-6 , includes ethylene/methacrylic acid (E/MAA), with an acid content of 0-30%, and a melt index from 10 to 3500 with a melt index range of 20 to 2300 for some embodiments. A low density polyethylene with a melt index higher than 200 is also suitable for use. Other embodiments of the white layer include ethylene vinyl acetate copolymer resin, EVA, with vinyl acetate percentages up to 50%/EVA are modifiable with an additive such as DuPont Elvax, manufactured by DuPont de Neimours of Wilmington, Del. These resins have a Vicat softening point of about 40 degrees to 220 degrees C., with a range of 40 degrees to 149 degrees C. usable for some embodiments. Other resins usable in this fashion include nylon multipolymer resins with or without plasticizers with the same pigment percent or ash content nylon resin such as Elvamide, manufactured by DuPont de Neimours or CM 8000 Toray. Nylon polymers are also blendable with resin such as ENGAGE with or without plasticizers. These resins are applicable as a solution water base or a solvent base solution system. These resins are also applicable by extrusion or co-extrusion or hot melt application. Other suitable resins include Allied Signal Ethylene acrylic acid, A-0540, 540A, or AC 580, AC 5120, and/or AC 5180 or ethylene vinyl acetate, AC-400, 400A, AC-405(s), or AC-430. The silicone-coated layer 304 acts as a release-enhancing layer. When heat is applied to the image transfer sheet 104 , thereby encapsulating image imparting media such as ink or toner or titanium oxide with low density polyethylene, ethylene acrylic acid (EAA), or MEAA, ethylene vinyl acetate (EVA), polyester exhibiting a melt point from 20 C up to 225 C, polyamide, nylon, or methane acrylic ethylene acrylate (MAEA), or mixtures of these materials in the substrate layer 302 , local changes in temperature and fluidity of the low density polyethylene or other polymeric material occurs. These local changes are transmitted into the silicone coated release layer 304 and result in local preferential release of the low density polyethylene encapsulates, EVA, EAA, polyester, and polyamide. The silicone coated release layer is an optional layer that may be eliminated if the colored base 102 or peel layer is sufficiently smooth to receive the image. In instances where the silicone coated release layer 304 is employed, the silicone coated release layer may, for some embodiments wherein the release layer performs image transfer, such as is shown in FIG. 3 b , also include titanium oxide particles or other white pigment or luminescent pigment in a concentration of about 20% by volume. One other image transfer sheet embodiment of the present invention, illustrated at 400 in FIG. 4 , includes a substrate layer 402 , a release layer 404 and an image imparting layer 406 that comprises a polymeric layer such as a low density polyethylene layer, an EAA layer, an EVA layer or a nylon-based layer or an MAEA layer or polyester melt point of 20 C up to 225 degrees C. The image imparting layer is an ink jet receptive layer. In one embodiment, the nylon is 100% nylon type 6 or type 12 or a blend of type 6 and 12. The polyamides, such as nylon, are insoluble in water and resistant to dry cleaning fluids. The polyamides may be extruded or dissolved in alcohol or other solvent depending upon the kind of solvent, density of polymer and mixing condition. Other solvents include methanol, methanol trichloro-ethylene, propylene glycol, methanol/water or methanol/chloroform. One additional embodiment of the present invention comprises an image transfer sheet that comprises an image imparting layer but is free from an image receptive layer such as an ink receptive layer. The image imparting layer includes titanium oxide or other white pigment or luminescent pigment in order to make a white or luminescent background for indicia or other images. Image indicia are imparted, with this embodiment, by techniques such as color copy, laser techniques, toner, dye applications or by thermo transfer from ribbon wax or from resin. The LDPE polymer of the image imparting layer melts at a point within a range of 43°-300° C. The LDPE and EAA have a melt index (MI) of 20-1200 SI-g/10 minutes. The EAA has an acrylic acid concentration ranging from 5 to 25% by weight and has an MI of 20 to 1300 g/10 minutes. A preferred EAA embodiment has an acrylic acid concentration of 7 to 20% by weight and an MI range of 20 to 1300. The EVA has an MI within a range of 20 to 3300. The EVA has a vinyl acetate concentration ranging from 10 to 40% by weight. One other polymer usable in the image imparting layer comprises a nylon-based polymer such as Elvamide®, manufactured by DuPont de Nemours or ELF ATO CHEM, with or without plasticizers in a concentration of 10 to 37% by weight. Each of these polymers, LDPE, EAA, EVA and nylon-based polymer is usable along or with a resin such as Engage® resin, manufactured by DuPont de Nemours. Suitable plasticizers include N-butyl benzene sulfonamide in a concentration up to about 35%. In one embodiment, the concentration of plasticizer ranged from 8 to 27% by weight with or without a blend of resin, such as Engage® resin, manufactured by DuPont de Nemours. Suitable Elvamide® nylon multipolymer resins include Elvamide 8023R® low viscosity nylon multipolymer resin; Elvamide 8063® multipolymer resin manufactured by Dupont de Nemours. The melting point of the Elvamide® resins ranges from about 154° to 158° C. The specific gravity ranges from about 1.07 to 1.08. The tensile strength ranges from 51.0 to about 51.7 Mpa. Other polyamides suitable for use are manufactured by ELF ATO CHEM, or Toray. Other embodiments include polymers such as polyester No. MH 4101, manufactured by Bostik, and other polymers such as epoxy or polyurethane. The density of polymer has a considerable effect on the viscosity of a solution for extrusion. In one embodiment, 100% of a nylon resin such as DuPont Elvamide 80625® having a melting point of 124° C. or Elvamide 8061M®, or Elvamide 8062 P® or Elvamide 8064®, all supplied by DuPont de Nemours. Other suitable polyamide formulations include Amilan CM 4000® or CM 8000 supplied by Toray, or polyamide from ELF ATO CHEM M548 or other polyamide type. In an extrusion process, these polyamide formulations may be used straight, as 100% polyamide or may be blended with polyolefin elastomers to form a saturated ethylene-octane co-polymer that has excellent flow properties and may be cross-linked with a resin such as Engage®, manufactured by DuPont de Nemours, by peroxide, silane or irradiation. The Engage® resin is, in some embodiments, blended in a ratio ranging from 95/5 nylon/Engage® to 63/35 nylon/Engage®. The polyamide is, in some embodiments, blended with resins such as EVA or EAA, with or without plasticizers. Plasticizers are added to improve flexibility at concentrations as low as 0% or as high as 37%. One embodiment range is 5% to 20%. Other resins usable with the polyamide include Dupont's Bynel®, which is a modified ethylene acrylate acid terpolymer. The Bynel® resin, such as Bynel 20E538®, has a melting point of 53° C. and a melt index of 25 dg/min as described in D-ASTM 1238. The Bynel® has a Vicat Softening Point of 44 C as described in D-ASTM 1525-91. This resin may be blended with other resin solutions and used as a top coat primer or as a receptive coating for printing applications or thermo transfer imaging. For some embodiments, an emulsion solution is formed by dissolving polymer with surfactant and KOH or NaOH and water to make the emulsion. The emulsion is applied by conventional coating methods such as a roll coater, air knife or slot die and so forth. The polymeric solution is pigmented with up to about 50%, with a material such as titanium oxide or other pigment, or without plasticizers and is applied by conventional coating methods such as air knife, rod gater, reverse or slot die or by standard coating methods in one pass pan or in multiple passes. Fillers may be added in order to reduce heat of fusion or improve receptivity or to obtain particular optical properties, opacity or to improve color copy or adhesion. The present invention further includes a kit for image transfer. The kit comprises an image transfer sheet for a color base that is comprised of a substrate layer impregnated with titanium oxide, a release layer and an image imparting layer made of a polymer such as LDPE, EAA, EVA, or MAEA, MEAA, nylon-based polymer or mixtures of these polymers or blends of these polymers with a resin such as Engage® or other polyester adhesion that melt at a temperature within a range of 100°-700° C. The LDPE has a melt index of 60-1200 (SI)-g/minute. The kit also includes a colored base for receiving the image on the image transfer sheet and a package for containing the image transfer sheet and the colored base. Another embodiment of the present invention includes an emulsion-based image transfer system. The system comprises a colored base, such as a colored fabric, an image transfer sheet with a release coating and a polyamide. The polyamide is impregnated with titanium oxide or other white pigment or luminescent pigment in order to impart a white or luminescent background on the colored base. One other embodiment of the present invention, illustrated at 500 in FIG. 5 , is also utilized in a method for transferring an image from one substrate to another. The method comprises a step of providing an image transfer sheet 500 that is comprised of a substrate layer 502 , a release layer 504 , comprising a silicone coating 505 and a white layer 506 with a thickness of about 0.5 to 7 mils and having a melt index, MI, within a range of 40°-280° C. The substrate layer 502 is, for some embodiments, a base paper coated on one side or both sides. The base paper is, optionally, of a saturated grade. In one embodiment, the white layer 506 of the image transfer sheet 500 is impregnated with titanium oxide or other white or luminescent pigment. In one embodiment, the white layer 506 and a receiving layer 508 , contacting the white layer 506 are impregnated with titanium oxide or other white or luminescent pigment. In one embodiment, the nylon resin is applied by a hot melt extrusion process in a thickener to a thickness of 0.35 mils or 8 gms per square meter to about 3.0 mils or 65 gms per square meter to a maximum of about 80 gms per square meter. In one particular embodiment, the thickness is about 0.8 mils or 15 gms per square meter to about 50 gms per square meter or about 0.75 mils to about 2.00 mils. The nylon resin is, in another embodiment, emulsified in alcohol or other solvent or is dispersed in water and applied with conventional coating methods known in the industry. Next, an image is imparted to the polymer component of the peel layer 520 utilizing a top coat image-imparting material such as ink or toner. In one embodiment, the polymer coating is impregnated with titanium oxide or other white or luminescent pigment prior to imparting the image. The ink or toner may be applied utilizing any conventional method such as an ink jet printer or an ink pen or color copy or a laser printer. The ink may be comprised of any conventional ink formulation. An ink jet coating is preferred for some embodiments. A reactive ink is preferred for other applications. The image transfer sheet 500 is applied to the colored base material so that the polymeric component of the peel layer 520 contacts the colored base. The second substrate is comprised of materials such as cloth, paper and other flexible or inflexible materials. Once the image transfer sheet peel layer 520 contacts the colored base, a source of heat, such as an iron or other heat source, is applied to the image transfer sheet 500 and heat is transferred through the peel layer 520 . The peel layer 520 transfers the image, which is indicia over a white or luminescent field, to the colored base. The application of heat to the transfer sheet 500 results in ink or other image-imparting media within the polymeric component of the peel layer being changed in form to particles encapsulated by the polymeric substrate such as the LDPE, EAA, EVA, nylon or M/EAA or polyamides, or polyester, urethane, epoxies or resin-containing mixtures of these polymers immediately proximal to the ink or toner. The encapsulated ink particles or encapsulated toner particles and encapsulated titanium oxide particles are then transferred to the colored base in a mirror image to the ink image or toner image on the polymeric component of the peel layer 520 . Because the polymeric component of the peel layer 520 generally has a high melting point, the application of heat, such as from an iron, does not result in melting of this layer or in a significant change in viscosity of the overall peel layer 520 . The change in viscosity is confined to the polymeric component that actually contacts the ink or toner or is immediately adjacent to the ink or toner. As a consequence, a mixture of the polymeric component, titanium oxide or other white or luminescent pigment, and ink or toner is transferred to the colored base as an encapsulate whereby the polymeric component encapsulates the ink or toner or titanium oxide or other white pigment. It is believed that the image transfer sheet, with the white titanium oxide or other white or luminescent pigment background is uniquely capable of both cold peel and hot peel with a very good performance for both types of peels. EXAMPLE 1 EAA is extruded or co-extruded at 300 melt index (Dow Primacor 59801) with 30% titanium oxide ash content extruded on silicone coated base paper 95 g/meter squared for thicknesses as follows: 0.75 mils, 1.0 mil, 1.2 mils, 2.2 mils, 2.75 mils, 3.5 mils, 7.0 mils. The EAA layer is coated with ink jet receptive layers and then printed on an ink jet printer. The print is then removed from the release layer to expose the print. The exposed print is applied against fabric and covered by release paper, wherein the release side contacts the printed side. The printed image is transferred by heat application with pressure, such as by an iron, at 250 F to 350 F for about 15 seconds. This procedure is usable with a blend of 80/20, 70/30, 50/50, 60/40 or vice versa, Dow Primacor 59801 and 59901. This procedure is also usable with DuPont Elvax 3180, or 3185 DuPont Nucrel 599, DuPont Nucrel 699, Allied Signal AC-5120 or an EAA emulsion of Primacor or Allied Signal 580 or 5120 resin or EVA or make a wax emulsion or EVA or EAA emulsion, or is blended with ELF 548 or Elvamide or polyester resin from Bostik MLT 4101. The emulsion is blended with titanium or white pigment in one or multiple layers and applied with conventional coating methods such as roll coating, myer rod, air knife, knife over or slot die. The blended emulsion is applied with a coat weight of 5 g/meter squared to 150 g/meter squared. The percent ash is about 7 to 80 percent with 10 to 70 percent for some embodiments. EXAMPLE 2 An ink receptive mono or multiple layer such as is shown in FIG. 6 at 604 , 606 , 608 and 610 includes a first layer 606 that includes 0 to 80% titanium pigment with acrylic or EVA or polyvinyl alcohol, or SBR with a Tg glass transition of −60 up to 56 with a range of −50 to 25, for some embodiments. In another embodiment, a wax emulsion is used with a coat weight of 5 g/meter squared to 38 g/meter squared with a range of 8 g/meter squared to 22 g/meter squared for some embodiments. In another embodiment, a pigment is blended to make layer 606 . EAA or EVA solution solvent or a water base solution and a different coat and different thickness are employed. On top of extruded layers, top coats 608 and 610 comprise ink receptive layers. This construction imparts an excellent whiteness to the background of a print with an excellent washability. EXAMPLE 3 For one image transfer sheet, such as is shown at 600 in FIG. 6 , a blend is prepared. The blend includes the same ratio of ash to emulsion of EAA or EVA or a blend of both of these polymers. The blend has a MEIT index of 10 MI to 2500 MI with a range of 25 MI to 2000 MI for some embodiments. The blend is formed into a substrate layer 602 , which can be coated on one side or both. The optionally coated substrate layer 602 is further coated with a release layer 604 that is coated with ink jet receptive layers 606 and 608 . The ink jet receptive layer or layers 606 and 608 include 50 percent titanium or barium talc, or a combination of different high brightness, high opacity pigments. These layers are coated within a range of 5 g/meter squared to 50 g/meter squared. In one embodiment, the range is 8 g/meter squared to 30 g/meter squared. EXAMPLE 4 As shown at 700 in FIG. 7 , a polyester resin obtained from Bostek MH 4101 was extruded to thicknesses of 0.5 mils, 1.0 mils, 2.0 mils and 4 mils with titanium oxide concentrations of 5%, 10%, 30%, and 40%, respectively, against silicone coated 705 paper 702 , having a density of 80 g/m-sq. The silicone coated 705 paper 702 was top coated with an EAA solution 706 that included titanium oxide in a concentration of about 40%. This titanium oxide coated paper was then coated with an ink jet receiving layer 708 . The ink jet receiving layer 708 was coated with a “Glow in the Dark” containing layer or a temperature changeable pigment containing layer or a light changeable layer 712 . These layers were ink jet printed, as required. As shown at 800 in FIG. 8 , the peeled printed layers 820 , including at least one or more layers collectively comprising a white or luminescent pigment and received indicia, were then placed against a fabric 854 and covered with release paper 852 . Heat 850 was applied to the peeled printed layers 820 and the release paper 852 . The heat 850 was applied at 200 F, 225 F, 250 F, 300 F, 350 F, and 400 F. A good image transfer was observed for all of these temperatures. EXAMPLE 5 An image transfer sheet was prepared in the manner described in Example 4 except that a polyamide polymer layer was coextruded using polyamide from ELF ATO CHEM M 548. EXAMPLE 6 An image transfer sheet was prepared in the manner described in Example 4 except that a blend of polyamides and DuPont 3185 in ratios of 90/10, 80/20, 50/50, 75/25 and 10/90, respectively was prepared and coextruded to make image transfer sheets. Each of the sheets displayed a good image transfer. EXAMPLE 7 An image transfer sheet was prepared in the manner described in Example 4 except that a blend of EAA and polyamide was prepared and coextruded to make image transfer sheets. Each of the sheets displayed a good image transfer. Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. The above Detailed Description includes references to the accompanying drawings, which form a part of the Detailed Description. The drawings show, by way of illustration, specific embodiments of present subject matter. These embodiments are also referred to herein as “examples.” The above Detailed Description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more elements thereof) can be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. Also, various features or elements can be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter can lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the event of inconsistent usages between this document and any document so incorporated by reference, the usage in this document controls. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” The terms “including” and “comprising” are open-ended, that is, an article, system, kit, or method that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. The Abstract is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
An image transfer article can include an image-imparting member and a removable substrate disposed adjacent to the image-imparting member. The image-imparting member can have a softening point temperature less than about 220° C. The image-imparting member can include at least one surface configured to receive and carry indicia to be transferred and at least one portion comprising a pigment providing an opaque background for received indicia. In some examples, the image-imparting member can comprise a first polymer including the indicia and at least a second polymer including the pigment. In some examples, the image-imparting member can comprise a polymer including the indicia and the pigment. The indicia and the opaque background can be arranged to concurrently transfer to a woven- or fabric-based article or paper in contact with the image-imparting member, upon application of iron pressing temperatures.
1
CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of co-pending International Application No. PCT/EP02/10545, filed Sep. 19, 2002, which designated the United States and was not published in English. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for an optical measuring of an OPC structure, in particular for measuring an OPC structure associated with a predetermined structure on a photo mask. 2. Description of the Related Art The trend in semiconductor manufacturing goes more and more toward smaller and smallest structures. The common method here is the illumination of wavers using photomasks by means of light (e.g. using visual wavelengths or wavelengths in the UV range), ion beams, electron beams, x-rays, or other methods to be mapped (lithography). At that, the structures to be mapped, like e.g. thin conductive traces or small contacts, are often in the range of or even smaller than the used wavelengths, which inevitably leads to mapping errors. The limits for mapping for lithography methods which use visible light range from a structure size of about 350 nm to 400 nm, and the mapping limit for lithography methods which use UV light range from about 250 nm to 300 nm. In particular, due to the limited resolution, corners of structures or line ends are mapped strongly rounded off onto the waver. In order to achieve a better pattern fidelity compared to the original design or layout, the above-mentioned critical locations (corners, line ends) on the photomask are provided with OPC structures or OPC-similar structures (OPC=Optical Proximity Correction). In connection with the present description, the term OPC structure refers to any structure or any element which is added to a photomask in order to guarantee or support, respectively, the true mapping of the mask onto a substrate. The OPC structures serve to change the structures actually to be generated on the photomask in a deliberate way in order to achieve a better mapping on the waver, i.e. for example less rounded at the corners. With reference to FIG. 1 , in the following two examples for the layout of OPC structures for the generation of photomasks are described. In FIG. 1A a section 100 of a layout is shown including a portion of a first structure 102 . In order to prevent a roundoff in the area of the corner 104 due to the mapping of the layout 100 onto the photomask, an OPC structure 106 is provided there protruding beyond the horizontal edge 108 and the vertical edge 110 of the structure 102 in the area of the corner 104 . In the example shown in FIG. 1A for a layout, the OPC structure 106 is substantially square. The OPC structure at the corner 104 shown in FIG. 1A is also referred to as corner serif. In FIG. 1B a section 200 of a layout is shown together with a portion of a second structure 202 . The second structure 202 is a line, and in the section 200 of the layout the line end of the structure 202 is illustrated. The structure 202 includes two parallel vertical edges 204 and 206 and a horizontal edge 208 connected to the vertical edges 204 and 206 in the area of a first corner 210 and in the area of a second corner. When transmitting the layout 200 onto a photomask, a similar problem results as in the transmission of the layouts described with reference to FIG. 1A , i.e. that the structure generated on the photomask in the area of the corners 210 and 212 is rounded off, so that also here, similar to FIG. 1A , an OPC structure needs to be provided in the area of the corners 210 and 212 . In FIG. 1B two OPC structures 214 and 216 are arranged in the area of the corners 210 and 212 , respectively, wherein the OPC structures respectively protrude beyond corners 204 and 208 and 206 and 208 , respectively. As in FIG. 1A , also here the OPC structures are basically of a square nature. The structure shown in FIG. 1B is also referred to as line end serifs. A special case of theses OPC structures in which the serifs are adjacent to each other at the line end is also referred to as a hammerhead. Conditional on the function, the OPC structures 106 , 214 , and 216 illustrated in FIGS. 1A and 1B are very small (approx. 200 nm and smaller). Instead of the structures described in FIG. 1 also other structures and elements are possible, e.g. so-called jogs or scatterbars, in order to improve the edge quality. In the conventional quality testing and quality assurance of photomasks for example generated using the layouts as they were described with reference to FIGS. 1A and 1B using optical microscopy, these small dimensions of the OPC structures represent a special challenge. Further, due to the high number of OPC structures in different spatial orientations on only one photomask a demand exists for an automatic method for the recognition and measuring of these structures. SUMMARY OF THE INVENTION Based on this prior art it is the object of the present invention to provide a method enabling the optical measuring of an OPC structure associated with a predetermined structure on a photomask with a minimum effort. The present invention provides a method for an optical measuring of an OPC structure ( 306 ; 406 ) associated with a predetermined structure ( 302 ; 402 ) on a photo mask with the following steps: (a) specifying an area ( 300 ; 400 ) on the photomask including the OPC structure ( 306 ; 406 ) to be measured and a first edge ( 310 ; 404 , 406 ) of the predetermined structure ( 302 ; 402 ). (b) sampling of the intensity image of the specified area ( 300 ; 400 ) row-wise in a first direction perpendicular to the first edge ( 310 ; 404 , 406 ) of the predetermined structure ( 302 ; 402 ), and for each row: (b.1) determining the location in which the intensity passes a threshold, and (c) based on the locations specified in step (b.1), determining a location lying farthest out with reference to the predetermined structure ( 302 ; 402 ), and a location lying farthest in with relation to the predetermined structure ( 302 ; 402 ); and (d) determining the maximum distance between the first edge ( 310 ; 402 , 404 ) of the predetermined structure ( 302 ; 402 ) and a first edge ( 312 ; 414 , 416 ) of the associated OPC structure ( 306 ; 406 ) based on the difference of the location lying farthest out and the location lying farthest in. According to a first embodiment, the structure is measured in two directions. In this case, first of all a sampling of the intensity of the specified area in a second direction is performed, and for each sampling in the second direction a location is determined in which the intensity passes a threshold and the maximum distance between an edge of the structure and an edge of the associated OPC structure is determined based on the difference of the specified locations. Alternatively, instead of the additional sampling in the second direction, the photomask may be rotated and the sampling is repeated in the first direction. According to a further embodiment of the present invention, the threshold is determined based on the intensities associated with the structure and a background of the structure. According to a further preferred embodiment, after specifying an area on the photomask first of all the type of the structure and/or the orientation of the structure with regard to a reference position is identified. The type of the structure is preferably identified by sampling the determined area along the edges of the area. For identifying the corner serif, the sampling of the corners of the area is sufficient. In other cases, the intensity course or the number of intensity transitions between light and dark along all edges is used, respectively, to determine the type of the structure. The present invention enables an automatic method, which firstly enables the recognition of a “corner serif”, “line end serifs”, or other OPC or OPC-similar structures on a photomask with a minimum effort on the operator side and to measure the same with a sufficient accuracy. The inventive method reduces errors that may be caused by the operator, as it operates objectively and thus eliminates errors caused by subjective assessments. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and features of the present invention will become clear from the following description taken in conjunction with the accompanying drawings, in which: FIG. 1A shows a schematical illustration of a layout for a portion of a photomask, wherein the layout shows a corner with corner serif; FIG. 1B shows a schematical illustration of a layout for a portion of a photomask, wherein the layout shows a line end with line end serifs; FIG. 2A shows a section of a photomask generated using the layout section of FIG. 1A ; FIG. 2B shows a section of a photomask generated using the layout of FIG. 1B ; FIG. 3A shows an example for the edge probing in the x direction with line end serifs; and FIG. 3B shows an example for the edge probing in y direction with line end serifs. DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 2A an illustration of an intensity image (section 300 ) of a photomask is shown generated using conventional imaging methods, e.g. by a microscope with an associated CCD camera. Alternatively, it may also be an SEM image or another image, which was generated by other imaging methods. In FIG. 2A a section 300 of a photomask is shown, wherein the section 300 was generated by transmitting the layouts of FIG. 1A onto a photomask. The section 300 includes a portion of a photomask structure 302 including a corner 304 . In the area of the corner 304 of the structure 302 on the photomask the OPC structure 306 was generated which, compared to the structure in the layout (see FIG. 1A ), was generated with rounded-off edges on the photomask. As it may be seen, the OPC structure 306 is implemented such that the same protrudes beyond a horizontal edge (in the x direction) of the structure 302 and beyond a vertical edge 310 (in y direction) of the structure 302 . In order to test the generated photomask with regard to its quality, it is required now to test the generated OPC structure 306 with regard to its dimensions, in particular with regard to the distance of the same from the edges 308 and 310 , in order to guarantee that the thus generated OPC structure 306 causes the desired correction in the corner area of the structure generated on the substrate in an application of the photomask for generating a structure on a substrate. According to the present invention, a method is provided which firstly enables to measure the distances dx and dy of the OPC structure 306 on the photomask from the structure 302 with a sufficient accuracy with a minimum effort from the operator side. Using an optical microscope, which is provided with a CCD camera, an intensity image of the photomask is generated containing the structure to be examined, i.e. the structure 302 with an associated OPC structure 306 . Around the structure to be examined an image section is defined, section 300 , which is the so-called ROI (ROI=Region of Interest). The selection of this area may either be performed manually by a user or, depending on whether the layout information is known, in an automatically controlled way. The size of the ROI 300 is not critical here, the only important thing is that the ROI 300 does not contain any other structures but only the structure 302 with the associated OPC structure 306 , which is to be measured. As soon as the area 300 is determined, the measuring is performed automatically by the inventive method. Due to the limited spatial resolution of the microscope, the ROI 300 contains a somewhat blurred mapping of the overall structure 302 , 306 to be examined. Otherwise, the structure 302 , 306 is mapped with an approximately constant brightness, and via the evaluation of the intensity distribution within the ROI 300 using a suitable method (e.g. histogram), a brightness of the structure 302 , 306 and a brightness of the background is established. Here, it is not important whether it is a bright structure in front of a dark background or a dark structure in front of a light background, as it is illustrated in FIG. 2A . After the ROI 300 has been determined, all edges of the overall structure 302 , 306 are probed in horizontal direction (x direction) and vertical direction (y direction). To this end, e.g. first in the x direction, the intensity in the area 300 is sampled, wherein for each sampling in the x direction the location is specified in which the determined intensity passes a threshold, i.e. for example an intensity signal of a value representing a light background changes to a value representing a dark background (See FIG. 2A ), whereby the presence of an edge within the photomask may be determined. The edge sampling is performed, as mentioned above, using the threshold value method, which uses a constant threshold which is preferably calculated from the mean intensities of the structure to be measured and the background. At that, the threshold value is selected so that the measuring error resulting from the limited resolution of the microscope and the blurring of the small OPC structure resulting from it is minimized. The sampling in the x direction is performed such that in each row a plurality of sampling points are selected for which the intensity is determined. The location in which an intensity change from light to dark takes place is determined for each row and based on the difference of the locations of the edge 310 of the overall structure 302 , 306 for each row, the maximum distance between an edge 312 of the OPC structure 306 and the edge 310 of the structure 302 to dx is determined. Analogue to this, a maximum distance between a horizontal edge 314 of the OPC structure 306 and the edge 308 of the structure 302 to dy is determined. In the area of the edge of the structure, the edge sampling with the smallest possible spatial resolution along the edge to be measured is performed. In case of a bad signal-to-noise ratio also a coarser spatial resolution may be selected, wherein then two or more rows or columns, respectively, perpendicular to the edge are combined. Due to the thus performed determination of the locations of the edges it is now possible to obtain all relevant dimensions of the OPC structure 306 overlaid over the structure 302 from the thus obtained edge profiles in horizontal direction and in vertical direction, i.e. the dimensions dx and dy for the corner serif, as it is shown in FIG. 2A . The final result consists of the dimensions of the OPC structure 306 both in horizontal direction and vertical direction, or the distance, respectively, by which the OPC structure is taller than the structure to be measured, wherein for the example shown in FIG. 2A a measurement value pair dx, dy is generated. Optionally, also the edge positions with regard to a predetermined reference position, the overall edge course resulting from individual samplings and the type of the found structure (type, orientation, light/dark) are output. In an alternative approach, instead of the sampling of individual points in the rows, one row or one column, respectively, is completely sampled in order to generate the sum of the intensity values of this sampling. The thus generated overall intensity values for each row or column, respectively, are compared to a first and a second threshold. For the embodiment illustrated in FIG. 2A , an overall intensity value below the first threshold indicates, that the row comprises no component of the structure 302 or the OPC structure 306 . Such a row is shown as an example in FIG. 2A at 316 . The second threshold defines the boundary between the OPC structure 306 and the structure 302 where an intensity exceeding the second threshold is regarded as a combination of the intensities resulting from the background and the structure 302 . Such a row is shown as an example at 318 . If an overall intensity of a completely sampled row lies between the first threshold and the second threshold, as it is indicated as an example in row 320 in FIG. 2A , this sampled overall row 320 only includes the OPC structure 306 . Thus it is possible to detect the edge 314 of the OPC structure 306 when passing the first threshold and to detect the edge 308 of structure 302 when passing the second threshold, and thus the distance of the edges 314 and 308 to each other or an absolute position of these edges, respectively, with regard to a predetermined reference point. Analogue to that, a corresponding approach is possible when sampling column by column. These approaches are only possible, however, when structures similar to those in FIG. 2A are to be sampled, i.e. when only one dimension is to be determined in one sampling direction. If several dimensions are to be detected in one sampling direction, then the row-wise or column-wise approach, respectively, provides no unique result, so that here again the sampling of individual sample points along one row is to be used. In FIG. 2B a section of a photomask is illustrated containing a structure which is obtained after mapping the layout of FIG. 1B onto the photomask. The section 400 shows a portion of a line 402 including two vertical edges 404 and 406 (in y direction) and a horizontal edge 408 (in x direction) connected to the vertical edges in the area of the corners 410 and 412 . In the area of the corners 410 and 412 the OPC structures 414 and 416 are formed which were generated in a rounded way compared to the layout in FIG. 1B on the photomask 400 due to the mapping technology. Similar to the method described as a first alternative with reference to FIG. 2A , here a distance of the vertical edge 404 of the structure 402 to the vertical edge 418 of the OPC structure 414 is determined to be the distance dx 1 . Further, a distance dy 1 of the horizontal edge 408 of the structure 402 to the horizontal edge 420 of the OPC structure 414 is determined. In the line segment 402 , subsequently further a distance dx 2 between the vertical edge 406 of the structure 402 and the vertical edge 422 of the OPC structure 416 is determined, as well as the distance dy 2 between the horizontal edge 408 of the structure 402 and the horizontal edge 424 of the OPC structure 416 . The proceedings are similar to the embodiment described with reference to FIG. 2A , it is to be noted, however, that two measurement values each are to be generated for every sampling direction. Thus, first in the x direction for each sampling a location of the edge 404 is determined and in the further sampling the location of the edge 406 and analogue to that the location of the edge 418 or the edge 422 , respectively, is determined, wherein from the difference of the thus determined locations a maximum distance dx 1 or dx 2 , respectively, between the edges 404 and 418 and 406 and 422 , respectively, is determined. Analogue to that, the locations for the edges 420 and 408 or 422 and 408 , respectively, are determined by sampling in the y direction, and from the difference of the locations detected for the edges a maximum distance of the edges dy 1 or dy 2 , respectively, is determined. The proceedings of detecting an overall intensity for one row or one column, respectively, described above as a second alternative with reference to FIG. 2A , is not possible in the embodiment shown in FIG. 2B , as by this no unique specification of the distances dy 1 or dy 2 , respectively, would be possible. Analogue to the method in FIG. 2A , for the line end serifs illustrated in FIG. 2B two measurement value pairs dx 1 , dy 1 , and dx 2 , dy 2 , are obtained, indicating the distance of the edges of the OPC structures to the edges of the structure 402 . Optionally, the edge positions with reference to a predetermined reference position, the overall edge course resulting from the individual samplings and the type of the found structure (type, orientation, light/dark) are output. Alternatively, it is also possible to respectively indicate the absolute positions of the edges with reference to a predetermined reference position. According to a preferred embodiment of the present invention, after specifying of the area of the photomask 300 or 400 to be examined it is determined what type of structure is arranged within the selected area 300 or 400 , respectively, in order to thus perform a case differentiation with regard to the steps to be performed for edge detection. If it is determined, for example, that a structure is contained in the area, as it is shown in FIG. 2A , then here, after reaching an edge in the x direction or the y direction, respectively, the search for a further edge may be terminated. Alternatively, as described above, the overall intensity of a row/column may be used. If it is determined, however, that a structure similar to the one in FIG. 2B is present in the area, then it is required to further detect the other edge after detecting one edge in one of the directions, in order to be able to perform the corresponding measurements. After the area 300 or 400 , respectively, was specified on the photomask, the type of structure contained within the same is identified by comparing a brightness course along all four borders or edges, respectively, of the portion 300 or 400 , whereby each structure may uniquely be identified due to the number of intensity transmissions from light to dark determined along each edge. At that, the type of structure (corner or line end), the intensity of the structure (light or dark) and the orientation of the structure with regard to the x or y direction are distinguished. The latter differentiation is facilitated by the fact that on typical photomasks all structures are either oriented horizontally or vertically. If this is not the case, however, the CCD camera itself may be rotated correspondingly and be automatically oriented to the structure. In the following, the determination of the intensity distribution in the intensity image, the corresponding determination of the threshold value and the identification of a structure according to a preferred embodiment of the present invention are described. First of all, the ROI is specified again and the brightness distribution is determined. Further, a threshold is specified, as it is described below. Using a histogram, the brightness distribution in the overall ROI is analysed. Maxima of the histogram distribution are searched for. The condition for this is that the maxima are clearly separated, i.e. that they are different by a certain minimum amount in brightness. A suitable function (Gaussian curve) is adjusted to the two highest maxima in order to determine the brightnesses (I 1 and I 2 ) corresponding to the maxima more accurately. I 1 and I 2 correspond to the mean brightnesses for “dark” and “light”. The absolute brightness threshold value S is calculated from I 1 and I 2 using S=s/ 100*( I 2 −I 1)+ I 1 wherein s is the relative threshold value (in %, commonly 50%) to be set by the user. This threshold value S is used both for the identification of the structure type and also for the later edge probing. Subsequently, the type of structure is determined. In the above-described embodiments only corners (corner serifs) and line ends (line end serifs) are identified. The expansion to other simple structure types is easily possible, however. The brightnesses in the four corners of the ROI are used in order to enable a first identification of the structure to be measured. For this, the four brightness values are compared to the threshold value S and identified as “light” or “dark” using the same. With a ratio of light/dark=1/3 and 3/1, the identification is clear; it can only be a corner serif. Simultaneously, by this the orientation and the differentiation “dark corner” or “bright corner” is determined and the identification may be ended. What is left is the line ends to be identified. With a corner ratio of light/dark=2/2 it can be no line ending; the identification is terminated with an error message. Only with a ratio of 0/4 or 4/0 can the identification be continued. Now, the ROI is searched along all four edges, and using the threshold value S transitions between light and dark are searched for. In case of a line end, only exactly two such transitions along exactly one edge may be present which then specify the type (light or dark) and the orientation of the line end. In any other cases, the identification is terminated with an error message. After type and orientation of the structure have been specified, now the measuring of the same is started. The measuring is subsequently described with reference to the line end serif OPC structure shown in FIGS. 3A and 3B . The strategy of edge probing depends on the preceding identification. In the following, the measuring of a “dark upper line end” with line end serifs 500 is described. The generalization to other structure types and orientations is trivial. The first sampling is performed row-wise in the x direction, as shown in FIG. 3A , wherein in FIG. 3A one starts at the bottom and proceeds row by row to the top to the line end (see arrow 502 ). In FIG. 3A a row 504 is shown as an example. If required, also two or several rows each may be combined into one. For each row the brightness profile 506 is extracted and from that, using the threshold value S, the positions of the two transitions light/dark are determined with a greatest possible accuracy. In the area of the line end serifs, four transitions are present; here, only the outer two transitions are measured. The sampling is terminated when no transition is visible any more in the profile, i.e. at the upper end of the line end serifs. Thus, the two edge courses left and right are obtained as a series of value pairs x left and x right . Firstly, the maxima (points of the structure lying farthest out) are determined left and right. Then, the minima (point of the structure lying farthest in) of the edge courses from the bottom boundary of the ROI to the height of the respective maxima are determined. From these four extreme values of the two edge courses left and right, the OPC dimensions dx 1 and dx 2 ( FIG. 2B ) are determined. The determination of dy 1 and dy 2 is performed similarly and is illustrated with reference to FIG. 3B . Here, the sampling is performed column-wise, wherein in FIG. 3B as an example a column 508 is shown. Starting from the middle 510 of the structure 500 (determined using the extreme values of the x edge courses in the last step) movements to the left and right are performed (see errors 512 , 514 ). For each column the brightness profile 516 is extracted and from this, using the threshold value S, the position of a transition light/dark is determined with a highest possible accuracy. At that, always only the topmost transition is measured and used if several transitions are found. The column-wise sampling is terminated as soon as no more transition are found left and right. For each column the position y of the brightness transition is obtained. The y values obtained for all measured columns determine the upper course of the edge. From the upper course of the edge first of all the maximum values (the topmost points) are determined left and right from the middle 510 , and the minimum value (bottommost point) from the part of the edge course between the two maximum values. From these three values the OPC dimensions dy 1 and dy 2 are obtained. Instead of the above-described structures, the inventive method may also be used for measuring other structures or elements, e.g. so-called jogs or scatterbars. The inventive method may also be used for the determination of an edge roughness of photomask structures. The present invention is not limited to the measuring of the structures and OPC structures described in the preferred embodiment, but is generally directed to the identification and measuring of OPC structures using optical microscopy or other mapping methods in an automatic run. Preferably, an identification of the type of structure and the overlaid OPC structure is performed based on an analysis of the brightness distribution in the intensity image or a section of the same, respectively. The actual measuring of the OPC structure is then performed by the above-described spatial high resolution edge sampling using a threshold value method adjusted to the microscope resolution. The inventive proceedings are used on all types of OPC structures and are not limited to those described above. While this invention has been described in terms of several preferred embodiments, there are alterations, permutations, and equivalents which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and compositions of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.
The invention relates to a method for optical measurement of an OPC structure ( 306 ), having a pre-determined structure ( 302 ) on a photo-mask, in order to determine a measurement of the structure in at least one direction, whereby, firstly, a region ( 300 ) is determined on the photo-mask, which comprises the OPC structure ( 306 ) to be measured. The intensity of the determined region ( 300 ) is then scanned in a first direction and the region in which the intensity passes a threshold is determined for each scan. The maximum separation between an edge ( 308 ) of the structure ( 302 ) and an edge ( 312 ) of the corresponding OPC structure ( 306 ) is determined, based on the difference of the determined regions.
6
BACKGROUND [0001] The present invention relates to synchronization of data between cellular devices. [0002] Computers are becoming increasingly powerful, lightweight, and portable. The computing power of computers that once filled entire rooms is now residing on a desktop. Laptop, notebook, and sub-notebook computers are virtually as powerful as their desktop counterparts. Even smaller hand-held computers are now capable of computing tasks that required much larger machines a few short years ago. [0003] As a part of this trend, computerized personal organizers are becoming increasingly popular with a large segment of the population. Computerized personal organizers tend to be small, lightweight, relatively inexpensive, and can perform such functions as keeping a calendar, an address book, a to-do list, etc. For example, people use computers and handheld devices to maintain information that includes, for example, calendar and personal information manager (“PIM”) data, in addition to information contained in files such as word processing documents. Examples of a pen-based handheld system include the Newton pen-based computer from Apple Computer, Inc., the Palm handheld from Palm Computing, Inc. and the Windows/CE handheld from various manufacturers such as HP/Compaq and Casio, among others. More recently, cellular telephones have added PIM functionality as well as picture capture and sharing capability. [0004] To address file synchronization issues, U.S. Pat. No. 5,845,282 discloses a method and apparatus for selecting and retrieving computer data files from a remote computer includes an automatic file translation mechanism. In one embodiment, the data being retrieved and the file translation mechanism are located on the same computer. The method of the invention includes establishing a data transfer link with the remote computer, displaying the files available for retrieval from the remote computer, selecting a file to be transferred, and translating the file prior to transfer. In one embodiment, the apparatus includes a pen-based computer and the remote computer is a desktop computer. [0005] U.S. Pat. No, 6,000,000 discloses an extendible file synchronization system for sharing information between a handheld computer system and a personal computer system. The synchronization system is activated by a single button press. The synchronization system proceeds to synchronize data for several different applications that run on the handheld computer system and the personal computer system. If the user gets a new application for the handheld computer system and the personal computer system, then a new library of code is added for synchronizing the databases associate with the new application. The synchronization system automatically recognizes the new library of code and uses it during the next synchronization. [0006] Many cell phones operate as stand alone units wherein the user enters all the information into the cell phone and the information is retrieved out of the cell phone alone. Other cell phones operate in conjunction with personal computer systems such that the cell phones and the PCs can transfer data back and forth when the cell phones are synchronized with the PCs. [0007] U.S. Pat. No. 5,491,507 discloses a telephone which permits a user to transmit and receive pictures and speech with a casing held in one hand. A speaker is arranged at the upper end part of the front of the casing which is thin and vertically long, while a microphone is arranged at the lower end part thereof. A display panel and a control panel are interposed between the speaker and the microphone. A camera is mounted on the casing so as to be capable of altering its angle. The speaker is detachably mounted, and it is usable as an earphone when detached. The user's movements are not hampered during the transmission and reception, and the equipment can assume various communication or service attitudes conforming to the contents of information for the communications. [0008] FIG. 1 shows an exemplary cell phone with a camera for taking pictures or videos. As mentioned in the '507 patent, the phone 1 is mainly constructed of the body 2 thereof which is thin and flat and which is in a vertically long shape, a camera 3 which is turnably mounted on the right side surface of the body 2 , an ear pad 4 which is foldably mounted on the upper part of the front of the body 2 , a speaker 6 which is arranged at the central part of the ear pad 4 , an antenna 21 which is mounted on the right side of the top surface of the body 2 , and a battery assembly 9 which is detachably mounted on the lower part of the rear surface of the body 2 . In addition, a grip 35 (chamfered parts 35 a ) is formed extending from the rear surface of the handy type video telephone equipment 1 to both the side surfaces thereof. A display panel 11 , a transmission/reception key 12 , a termination key 13 , a control panel 14 , function keys 15 , and a microphone 16 are arranged on the front surface of the body 2 , in addition to the ear pad 4 . The phone includes a processor and a memory, a communication device which includes a radio/video codec, a speaker, a display panel, a control circuit, a microphone, a battery, an antenna 21 , and the camera 3 . Additionally, Bluetooth and/or 802.11 transceivers are coupled to the control circuit so that the phone 1 can communicate with a WLAN. [0009] Recently, smart phones such as AudioVox's SMT5600 run on Microsoft's Windows Mobile 2003 OS and contain built-in VGA cameras that take both still and video images. When finished with taking the photos, the user can save them to the phone or send them to friends via a multimedia message, Bluetooth, or an infrared port. In addition to Bluetooth, WiFi capable cellular phones have appeared. For example, Nokia's 9500 Communicator is a tri-band voice device with wide color screen and full keyboard, email, web and office applications, and the ability to connect to compatible company and public network via high-speed 802.11 Wireless LAN, GPRS and EDGE. With this device, the user can access the Internet without incurring cellular data charges whenever the user is within range of an 802.11 Wireless LAN. SUMMARY [0010] Systems and methods are disclosed for communicating image data between a first cell phone and a remote processor by capturing image data using a first cell phone camera; connecting with the remote processor; and synchronizing images stored in the first cell phone with images stored in a data storage device coupled to the remote processor. [0011] Implementations of the above systems and method can include one or more of the following. The synchronizing of images is performed automatically without an explicit user request. The remote processor can be a second cell phone or a server. The system can communicate over one of: a cellular protocol, an 802.11 protocol, a Bluetooth protocol. When communicating over a wireless local area network (WLAN) protocol, the system synchronizes image data only when excess WLAN bandwidth is available. In one embodiment, the WLAN has a maximum upload bandwidth, and the system determines current data transmission utilization of the WLAN; and synchronizes image data only when the current data transmission utilization of the WLAN is below the maximum upload bandwidth of the WLAN. The server can print the image data or simply archive the image data. [0012] In another embodiment, the system automatic downloads images from a phone via Bluetooth or Wi-Fi protocol when in proximity of a home network or other device. The system enables the automatic transfer of multimedia data from a camera or cell phone when in proximity of a wireless hotspot. The system automatically senses when the multimedia device is in range of an appropriate wireless hotspot and begin a transfer of the data to an appropriate server over the network. This mechanism allows the user to take pictures or other multimedia and not have to go through an explicit export step. The data would be made available from the new server location for printing, sharing and archiving, and any other use. The portable device can be any of a number of digital appliances with Bluetooth and/or WiFi such as for example, a camera cell phone, a digital still or digital video camera, set-top box, game machine, photo appliance, and the like. [0013] Advantages of the system may include one or more of the following. The system enables authorized cell phones to synchronize images with each other. The system frees up the memory in the camera cell phone for taking more pictures without having to swap out memory cards as in conventional systems. Another advantage is that it affords the user the ability to wireless synchronize all associated multimedia assets, such as digital photos, and/or albums that contain digital images. Thus, if a particular multimedia asset is captured, the information can be automatically shared with other cell phones. This synchronization is accomplished efficiently and automatically by, in one embodiment, transparently transferring newly captured images whenever the device detects an available wireless network. BRIEF DESCRIPTION OF THE DRAWINGS [0014] FIG. 1 shows a prior art cell phone with a camera for taking pictures or videos. [0015] FIG. 2 illustrates a first method of transferring information between cell phones. [0016] FIG. 3 shows an exemplary user-activated image file synchronization process. [0017] FIG. 4 shows an exemplary automatic image file synchronization process without user instruction. [0018] FIG. 5 shows an exemplary automatic image file synchronization process between a cell phone and a server on a WLAN without user instruction. DESCRIPTION [0019] FIG. 2 illustrates a system for transferring information between cell phones 110 and 150 or other suitable portable communication systems. In the cell phone 110 in FIG. 2 , a first file transfer program 210 runs on the cell phone 110 to manage file transfers from the first cell phone. The file transfer program 210 on the first cell phone 110 communicates with a local file system 220 responsible for creating and storing files such as image files. The file transfer program 210 on the first cell phone 110 communicates across a communication link 140 (such as a wired link or a wireless link over 802.11, Bluetooth, or GPRS protocols, among others) to second cell phone file transfer program 250 that runs on the second cell phone 150 . The file transfer program 250 communicates with a local file system 260 on the cell phone 150 . The file transfer program 210 on the first cell phone 110 also communicates over the communication link 140 to a server 160 through a server file transfer program 252 that runs on the server 160 . The file transfer program 252 communicates with a local file system 262 on the server 160 . [0020] For security, in one embodiment, a link encryption for either Bluetooth or 802.11 transmissions is done as a stream cipher using 4 LFSR (linear feedback shift registers). The sum of the width of the LFSRs is 128, and the effective key length is selectable between 8 and 128 bits. Key generation and authentication is done using an 8-round SAFER+ encryption algorithm. In one embodiment, to minimize “bluesnarf attack” the cell phone's ‘visible’ mode is turned off. Additionally, a login process is performed in another embodiment where the user enters a user ID and a password before data transmission can occur. [0021] In one embodiment, to minimize data transmission requirement a user may indicate that images may be shared one at a time or, alternatively, a plurality of images can be marked for sharing/synchronization of images and associated image data. Only selected images are then shared with other cell phones. [0022] To invoke the file transfer system of FIG. 2 , two methods shown in FIG. 3 and 4 can be used. FIG. 3 shows an exemplary user-activated image file synchronization process. In this process, a first user executes the file transfer program 210 on the cell phone 110 ( 260 ), and a second user executes the file transfer program 250 on the second cell phone 150 ( 261 ). The file transfer program 210 accesses the second phone 150 over the communications link 140 ( 262 ), and the file transfer program 210 authenticates the second phone 150 ( 263 ). Upon authentication, file transfer program 210 retrieves file names from the local file system of phone 150 ( 264 ) and performs a comparison to detect differences in the image files ( 265 ). Files in phone 110 but not in phone 150 are sent to storage memory on the phone 150 and local file system of phone 150 is updated ( 266 ) and files in phone 150 but not in phone 110 are copied to storage memory on the phone 110 and local file system of phone 110 is updated ( 267 ). [0023] FIG. 4 shows an exemplary automatic image file synchronization process without user instruction. In this process, software can detect the presence of an authorized cell phone on the communications link 140 and automatically initiates an image synchronization process. The process first detects when the phone 110 is in range of a wireless network over communications link 140 ( 280 ). If so, the process also detects if the phone 150 is also on the wireless network ( 281 ). Without an explicit user request, file transfer program 210 accesses the second phone 150 over the wireless communications link 140 ( 282 ). The file transfer program 210 authenticates the second phone 150 ( 283 ). Upon authentication, file transfer program 210 retrieves file names from the local file system of phone 150 ( 284 ), and the file transfer program 210 compares the files in the second phone 150 local file system ( 285 ). Files in phone 110 but not in phone 150 are sent to storage memory on the phone 150 and local file system of phone 150 is updated ( 286 ), while files in phone 150 but not in phone 110 are copied to storage memory on the phone 110 and local file system of phone 110 is updated ( 287 ). [0024] FIG. 5 shows an exemplary automatic image file synchronization process with a server. The cell phone 110 can communicate over the WLAN to a server 160 that is connected to the Internet. As would be evident to one of ordinary skill in the art, the server 160 includes a CPU, hard disk, memory, and Internet access such as a modem, network interface card, or a cable modem. Having access to the Internet, the server can transfer image data from the cell phone to a photofinisher. When within range of the WLAN, the system transfer data automatically to the storage space of the server 160 from the data storage device of the user's cell phone 110 . The cell phone's WLAN transceiver then transmits the pictures over the WLAN. Alternatively, when WLAN is not present and the cell phone data storage device is almost full, the cell phone can transmit images through the cellular network (preferably using 3G) to the home-based server for storage thereon. In that case, the cell phone calls the server's modem and transmits data to the server over the POTS network. [0025] In FIG. 5 , software can detect the presence of a WLAN on the communications link 140 and automatically initiates an image synchronization process with a server connected to the WLAN. The process first detects when the phone 110 is in range of a wireless network over communications link 140 ( 290 ). If so, the process also detects if an authorized server is also accessible to the wireless network ( 291 ). Without an explicit user request, file transfer program 210 accesses the server over the wireless communications link 140 ( 292 ). The file transfer program 210 authenticates the server ( 293 ). [0026] Upon authentication, file transfer program 210 retrieves file names from the local file system of the image server ( 294 ), and the file transfer program 210 compares the files in the server's file system ( 295 ). Files in phone 110 but not stored on the server are sent to the server disk space and server file system is updated ( 296 ), while files in the server but not in phone 110 are copied to storage memory on the phone 110 and local file system of phone 110 is updated ( 297 ). [0027] In one embodiment, the syncing of multimedia data is achieved without disrupting existing WLAN data transfer speed. This is done by syncing the data back to the network server over the wide area wireless network only when surplus data bandwidth is available and only excess bandwidth is consumed to synchronize image data between the cell phone and the server. The system thus synchronizes image data only when excess WLAN bandwidth is available. In one embodiment, the system determines the WLAN's maximum upload bandwidth, determines current data transmission utilization of the WLAN; and synchronizes image data only when the current data transmission utilization of the WLAN is below the maximum upload bandwidth of the WLAN. [0028] In the embodiment of FIGS. 3-5 , to speed up the synchronization of images between the two cell phones, the file transfer system 210 operates only on individual files in the two computer systems such that no individual record analysis is done. For example, the file transfer programs on both cell phones can compare the dates of files on each system and transfer the more recent version from one system over to the other. This is efficient for image file transfers since it is unlikely that users would edit or otherwise alter image data files on the cell phones. In other embodiments, cell phones with matching applications can share information on a record level. For example, an address book containing names, pictures, phone numbers, and addresses of people in records can be merged at a record level. [0029] In this disclosure and claims, the terms “transfer” and “transmit” or their derivatives are may be equivalent when transference is done through transmission. Images include image data and image data includes images. Also, in this disclosure and claims, the term “automatically” is meant to mean that something is done without the need for further input from a user. [0030] It is to be understood that various terms employed in the description herein are interchangeable. Accordingly, the above description of the invention is illustrative and not limiting. Further modifications will be apparent to one of ordinary skill in the art in light of this disclosure. [0031] The invention has been described in terms of specific examples which are illustrative only and are not to be construed as limiting. For example, although the buffer memory is described as high speed static random access memory (SRAM), the memory can be any suitable memory, including DRAM, EEPROMs, flash, and ferro-electric elements, for example. The invention may be implemented in digital electronic circuitry or in computer hardware, firmware, software, or in combinations of them. [0032] Apparatus of the invention may be implemented in a computer program product tangibly embodied in a machine-readable storage device for execution by a computer processor; and method steps of the invention may be performed by a computer processor executing a program to perform functions of the invention by operating on input data and generating output. Suitable processors include, by way of example, both general and special purpose microprocessors. Storage devices suitable for tangibly embodying computer program instructions include all forms of non-volatile memory including, but not limited to: semiconductor memory devices such as EPROM, EEPROM, and flash devices; magnetic disks (fixed, floppy, and removable); other magnetic media such as tape; optical media such as CD-ROM disks; and magneto-optic devices. Any of the foregoing may be supplemented by, or incorporated in, specially-designed application-specific integrated circuits (ASICs) or suitably programmed field programmable gate arrays (FPGAs). [0033] While the above embodiments have involved application of luminescent substances to dental structures, the invention is applicable to all non-opaque surfaces. [0034] Although an illustrative embodiment of the present invention, and various modifications thereof, have been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to this precise embodiment and the described modifications, and that various changes and further modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.
Systems and methods are disclosed for communicating image data between a first cell phone and a remote processor by capturing image data using a first cell phone camera; connecting with the remote processor; and synchronizing images stored in the first cell phone with images stored in a data storage device coupled to the remote processor.
7
This is a continuation of application Ser. No. 07/940,202 filed on Sep. 1, 1992/now abandoned, which is a continuation of U.S. Ser. No. 07/664,370, filed Mar. 4, 1991 which is now abandoned. BACKGROUND OF THE INVENTION It is recognized in the art that in aqueous iodine compositions wherein the iodine is formulated with organic substances with which it reacts, such as water soluble organic solvents, iodine complexing polymers or surface active agents, the elemental iodine concentration decreases on storage leading to decreased germicidal effectiveness and lack of reproducibility of results. One method of overcoming the problem of elemental iodine stability which has been suggested involves adding iodate or iodide ions to the aqueous solution. For example, U.K. Specification No. 2060385, describes aqueous germicidal iodine compositions comprising an aqueous solution of elemental iodine and at least one organic substance which slowly reacts with iodine wherein iodine loss on storage due to reaction with the organic substance is controlled by providing balanced sources of iodide ion in the range of about 0.025% to 0.5% and iodate ion in the range of about 0.005% to 0.2% and controlling the pH within the range of pH 5 to 7. In this way, iodine loss in the iodine composition is balanced by iodine formed from reacting iodate, iodide and hydrogen ions, the rate of formation of iodine being governed by the pH selected. The need for stable pharmaceutical iodine compositions with less irritancy than known compositions still exists. SUMMARY OF THE INVENTION It is accordingly a primary object of the present invention to provide stable pharmaceutical iodine compositions with reduced irritancy. It is another object of the present invention to provide for the method of producing such compositions and further to provide for germicidal treatment with such compositions. Other objects and advantages of the present invention will be apparent from a further reading of the specification and of the appended claims. Thus, the present invention relates to pharmaceutical iodine compositions, to processes for their preparation and to their medical use, and in particular, to stable germicidal iodine compositions in which the elemental iodine concentration level is maintained by the addition of iodate ions. With the above and other objects in view, it has been found according to the present invention that stable compositions with unexpectedly reduced irritancy are obtained by adding iodate ions in the range of 0.01% to 0.04% by weight to aqueous iodine compositions. Thus, the present invention provides a pharmaceutical composition comprising an aqueous solution of elemental iodine and at least one organic substance which reacts with iodine, whereby iodine loss is controlled by providing a source of iodate ions sufficient to provide from 0.01% to 0.04% by weight iodate ions, preferably from 0.02% to 0.03% by weight iodate ions. Suitable organic substances for use in the present invention include those conventionally used in the art. Those include for example, water soluble solvents (such as ethanol, propanol, polyethylene glycol); iodine solubilizers; iodine complexing polymers such as polyvinylpyrrolidone or non-ionic, cationic or anionic detergent carriers or surface active agents (such as nonoxynol or sodium lauryl sulphate). According to the invention, elemental iodine is preferably present in the range of 0.1 to 1.4% by weight, most preferably 0.75 to 1.25% by weight. Conveniently, the composition according to the invention comprises an aqueous solution of a complex of iodine with an organic iodine-complexing agent, preferably a polyvinylpyrrolidine-iodine complex. Where polyvinylpyrrolidone-iodine is used, the same is preferably present in the range of from 1% to 12% by weight to give from 0.1% to 1.4% of the available iodine in solution. The iodate ions for use in the present invention may be obtained from any convenient source for example sodium or potassium iodate. The pH range of compositions according to the present invention is desirably maintained within the range from pH 3 to 7, preferably pH 4 to 6. The pH is conveniently maintained in the desired range by addition of a conventional buffer such as a citrate or phosphate buffer. Compositions according to the present invention may be formulated for administration by any convenient route conventional in the art. Such compositions are preferably in a form adapted for use in medicine, in particular human medicine, and can conveniently be formulated in conventional manner using one or more pharmaceutically acceptable carriers or excipients. Compositions according to the present invention are conveniently formulated for topical or mucosal administration in the form of solutions, soaps, ointments, gels or paints. In a further aspect there is provided a process for preparing a pharmaceutical iodine composition according to the invention, comprising forming a solution of iodine and at least one organic substance with which iodine reacts and adding iodate ions in the range of from 0.01% to 0.04% by weight. In an alternative aspect, there is provided a method for the germicidal treatment of a mammal, including man, comprising administering a composition as defined above. It will be appreciated that reference to treatment is intended to include phophylaxis. BRIEF DESCRIPTION OF THE DRAWINGS The present invention is further illustrated in connection with the accompanying drawings in which: FIG. 1 is a graphical representation of mean visual erythema assessment; FIG. 2 is a graphical representation of mean erythema meter readings, and FIG. 3 is a graphical representation of blood flow measurements, all in connection with tests with respect to the compositions of the present invention. DESCRIPTION OF PREFERRED EMBODIMENTS The following example is given to further illustrate the present invention. The scope of the invention is not, however, meant to be limited to the specific details thereof. EXAMPLE The following iodine compositions were prepared. ______________________________________ I II (Comparative) III (ComparativeConstituents % w/w % w/w % w/w______________________________________Povidone-iodine 10.00 10.00 10.00(Overage %) (0) (20) (0)Glycerol 1.0 1.0 1.0Nonoxynol 9 0.25 0.25 0.25Potassium iodate 0.03 -- 0.225Citrate/phosphate 1.11 0.20 1.1Buffer (Approx.Sodium hydroxide q.s. q.s. q.s.Purified water to 100.00 to 100.00 to 100.00______________________________________ A portion of the purified water (60%) was placed in a suitable vessel. Glycerol was added and mixed until the solution was uniform. Povidone-iodine was mixed until dissolved. Potassium iodate was dissolved in a separate small quantity of purified water and added to the povidone-iodine solution. The citrate phosphate were dissolved in water and added to the solution with mixing following by the addition of Nonoxynol 9. The solution was made up with the remaining purified water and the pH adjusted to within the desired range. The cutaneous irritancy of the three compositions was assessed in a panel of 12 normal volunteer subjects. Each subject received 7 applications of each material under occlusive patches to separate sites on the back. The treatments were applied to 21 sites on the lower and upper parts of the back using 12 mm aluminum Finn chambers on Scanpor tape with filter paper inserts. 50 mol of the solution was pipetted onto the filter paper. The chamber and filter paper was then applied to one of the sites on the back and the procedure repeated for all 21 sites. One chamber per treatment was removed after 1, 2, 3, 4, 5, 6 and 8 hours following application and the skin assessed. Assessments were performed 30 minutes after removal of the chambers to allow for any erythema due to chamber removal to subside. Following removal of the chambers, irritancy was assessed using three procedures. Sites were assessed for erythema/oedema using the following categorical scale: 0 - No reaction 0.5 - Slight patch erythema 1 - Slight uniform erythema 2 - Moderate erythema 3 - Strong erythema 4 - Strong erythema, spreading outside patch 5 - Strong erythema, spreading outside patch with either swelling or vesiculation 6 - Severe reaction with erosion When at any time point a site was scored at Grade 3 (strong erythema) or more, then the applications were removed from all remaining sites of that solution on that subject. In this situation, the sites were assessed at the same time points as originally scheduled as if no severe reactions had occurred. Erythema was also assessed using an Erythema Meter. Cutaneous blood flow was measured using a Laser Doppler blood flow device (periflux blood flow meter, Perimed, Sweden). METHOD OF ANALYSIS In the clinical study the data was either non-parametric in nature or not normally distributed or not of equal variances. Therefore, it was decided that a non-parametric method of analysis was the most suitable. As the data is based on within subject comparison (each subject receiving all three treatments) the Friedman non-parametric analysis of variance was considered appropriate. Comparisons were made between treatments at t=1, t=2, t=3 and t=4 hours for the three parameters measured. If a significant value for the test statistic was found, then a multiple comparison procedure was carried out in order to determine individual treatment difference. The threshold value for significance was set at 5%. Analysis was not carried out at the later time points as in some subjects the treatments had been removed. RESULTS The results (means and standard deviations) for visual erythema assessment, erythema meter readings and blood flow measurements are shown in FIGS. 1-3. The results for all three methods of assessment show a clear difference in the irritancy potential of the three solutions. From the results it can be seen that composition III is the most irritant, producing the greatest rate of increase of parameters assessed as well as the highest mean value. Composition II produced the second highest values while composition I produced the least irritancy. Statistical analysis confirmed these differences at the 2, 3 and 4 hour time points. It will be appreciated that these time periods are important in the clinical situation of an operation. An in-vitro study to compare the bactericidal activity of solutions I, II and III using standard microbiological dilution techniques against a test bacterial organism, Staphylococcus aureus NCTC 29213 showed no difference in the bactericidal activity of the three solutions. While the invention has been illustrated with respect to particular compositions, it is apparent that variations and modifications of the invention can be made within departing from the spirit or scope of the invention.
A stable pharmaceutical composition with reduced irritancy is provided, the composition comprising an aqueous solution of elemental iodine and at least one organic substance which reacts with iodine, whereby iodine loss is controlled by providing a source of iodate ions in an amount sufficient to provide from 0.01% to 0.04% by weight iodate ions, preferably from 0.02% to 0.03% by weight iodate ions.
0
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machine designed for direct or indirect application of a liquid or viscous coating medium onto a moving surface. 2. Description of the Related Art Coating machines for direct or indirect application of a liquid or viscous coating medium onto a moving surface are generally well known and considered as state-of-the-art (ref GB 2 040 738 A). In the case of direct application, the moving surface includes an outer surface of a material web such as paper or cardboard. In the case of indirect application, the moving surface includes an outer surface of a transfer element, preferably a transfer roll which transfers the coating medium onto the material web. In order to achieve a uniform coating with such a coating mechanism, a coater must be uniformly supplied with a coating medium. That means that the pressure of the incoming coating medium has to be equally applied onto the coater across the entire coating width so that the coater is uniformly lifted off the moving surface to form a metering slot of the desired width. This applies to the application of a coater blade, as well as to a smooth or profiled coater rod. The “profile” of the coater rod can be generated by way of wire sheathing, machining, etching, or forming of impressions onto its surface. GB 2 040 738 does not deal with the problem of achieving a uniform coating, but introduces a concept that is capable of compensating for the surface wear of the coater bed supporting the coater rod. It should be further noted that GB 2 040 738 describes the coating medium being supplied to the coater as already having taken the shape of a thin film. An older, re-published document DE 197 23 458 A1 discloses a coating mechanism, which includes an accumulator chamber positioned downstream of the coater, whose boundaries are formed by an accumulator chamber inlet limiting element at the moving surface entrance and a coater at the moving surface exit. The main purpose of the accumulator chamber inlet limiting element is to keep air bubbles from entering the accumulator chamber. It cannot be discerned from GB 2 040 738 A that the coating quality can be influenced by the accumulator chamber positioned in front of the coater and by altering its geometry. The movement of the limiting surface of the coater facing the moving surface towards the moving surface serves to balance the wear in the intake area of the coater rod. This is only possible because the coating medium is supplied in form of a thin film and does not accumulate or “back up” in front of the coater rod. In terms of the subject matter, DE 197 213 458 differs by the fact that the accumulator chamber is open on one side; that means it is not bound by an accumulator chamber limiting element. SUMMARY OF THE INVENTION The present invention provides a coating mechanism that is capable of uniformly applying a liquid or viscous coating medium onto a moving surface. A machine is designed for direct or indirect application of a liquid or viscous coating medium onto a moving surface. In the case of direct application, the moving surface is an outer surface of a material web, such as paper or cardboard. In the case of indirect application, the moving surface is an outer surface of a transfer element, preferably a transfer roll designed to transfer the coating medium onto a material web. The machine further includes a coating mechanism with a coater bed and a coater, which, together with the moving surface, establish a metering slot. A limiting surface of the coater positioned at the inlet of the moving surface forms an accumulator chamber designed to accumulate or collect the coating medium transported by the moving surface. This chamber includes an opening at the side of the chamber opposing the feed direction of the moving surface. This chamber gradually decreases in volume in the feed direction of the moving surface. Such a chamber further includes an adjusting mechanism in order to alter the relative position of the limiting surface with respect to the moving surface and to thereby alter the shape of the accumulator chamber. The present invention has distinct advantages over prior art coating mechanisms. By providing a chamber ahead of the coater in which the coating medium accumulates, a transverse flow patterns builds upstream of the coater, i.e., the flow has components in a direction perpendicular to the moving surface. This cross-flow leads to a more even distribution of the coating medium across the width of the moving surface on one hand, and, on the other hand, to a more balanced pressure distribution of the accumulated coating medium. This has the consequence that the coater receives the coating medium more evenly, resulting in overall improvements in coating quality. An additional advantage of the accumulator chamber can be realized by changing the geometry of the accumulator chamber by use of an adjusting mechanism. This alters the hydrodynamic pressure in a very specific manner, which, in turn, affects the coating thickness without having to change the feed speed or the viscosity of the coating medium. When applying a coating mechanism that employs a coater rod, the provision of the accumulator chamber has the further advantage of minimizing the influence of the coater rod diameter, i.e., the surface curvature of the coater rod, on the hydrodynamic pressure acting upon it. More specifically, the combination of a coater rod having a small diameter and a limiting surface designed as described by the present invention can result in conditions that are normally only achievable with very large diameter coater rods. This allows for the advantages of coater rods with small diameters, such as the easier handling, lower manufacturing cost, etc., to be combined with the advantages of large diameter coaters such as the increased amount of coating medium that can be applied onto the moving surface per unit time, as well as the lower pressure being exerted onto the moving surface, etc. Additionally, when applying the coating mechanism in accordance to the present invention, it requires only a reduced number of coater rods with varying diameters to cover the full operating spectrum of the coating procedure. Finally, the even distribution of the coating medium in the accumulator chamber, and therefore, the improved pressure distribution in the coating medium, allows the pre-metering amount to be lowered, which, in turn, lowers the total amount of circulating coating medium and, hence, the required pumping power. It should be noted here that the above mentioned optimization of the operating conditions can be achieved not only with smooth coater rods, but also with profiled coater rods. An optimum color distribution can be achieved when using jets (for example slotted jets or spray jets, etc.) for the pre-metering of coating films in film presses. In general, this coating mechanism can be applied in coating equipment, which is commercially available through the corporation of the applicant under the name “Speedsizer”, “SpeedCoater” and “SpeedFlow”. Further advantages include the capability of achieving targeted shear stresses of the coating medium in the accumulator chamber, as well as the capability of affecting the mold clamping force of the coater bed to avoid color circles on the coater rod or to avoid coater rod vibrations. The above indicated advantages can be achieved especially when the length of the accumulator chamber, as measured in direction of feed, is between 2 mm and 100 mm, preferably between 5 mm and 50 mm, and/or when the width of the accumulator at the inlet is between 0.5 and approximately 5 mm, preferably between 0.5 mm and approximately 2 mm, as measured in a direction that is perpendicular to the direction of feed as well as perpendicular to the transverse direction of the moving surface. If the feed speed of the moving surface is relatively low, i.e. 900 m/min, an accumulator chamber length that is comparatively large with a relatively small inlet width can be applied. With an average feed speed of approximately 1000 m/min, the accumulator chamber length, as well as the inlet width, can also be mean values. In the case of higher feed speeds, especially when the speeds exceed 1500 m/min, a short accumulator chamber length having a large inlet width can be used. Of course, the above mentioned relative values are in reference to the absolute values of the accumulator length and inlet width stated at the beginning of this paragraph. If the coating mechanism is further equipped with a distribution chamber adjacent to the inlet of the accumulator chamber, the cross-flows, which are required to balance the pressure in the incoming coating medium, can be kept away from the metering slot by instituting simple design considerations. This further improves the quality of the coating result. With this additional development of the present invention, the pressure balancing occurs initially in the distribution chamber, which is further removed from the metering slot. The coating medium is subsequently fed through the narrower accumulator nip to the metering gap. The distribution chamber can have a length of between 5 mm and approximately 30 mm, for example, as measured in the direction of feed, and/or an inlet width ranging from approximately 4 mm to 11 mm, as measured in a direction that is perpendicular to the direction of feed as well as perpendicular to the transverse direction of the moving surface. In order to simplify the altering of the relative position of the limiting surface, which bounds not only the accumulator chamber but also the distribution chamber, the adjusting mechanism can be designed to be capable of simultaneously altering the shape of the accumulator chamber, as well as that of the distribution chamber. Altering the geometry of the accumulator chamber (and the distribution chamber) can be simply accomplished by adjusting a limiting surface of a coater bed. A coater bed has a base unit onto which the coater is attached, while the limiting surface is part of a tongue plate which is positioned at a distance relative to the base unit while being connected to it in a flexible manner. The adjusting mechanism can support itself on the base unit as well as on the coater bed. Alternatively, the same effect can be achieved by rotating the coater bed by moving an adjusting mechanism about an axis positioned in the transverse direction relative to the moving surface. If, as an additional measure, the tongue plate is supported at its free end by a support element of the coating mechanism, the approaching and receding movements of the limiting surface of the coater bed at a point along the tongue plate near the coater are amplified as compared to a point along the tongue plate that is further removed from the coater, which, once again, has a favorable impact on the pressure distribution of the coating medium accumulating in the area ahead of the coater. As an alternative to the above-described options detailing coater bed design and adjustment options, the coater bed can also be attached to a support element of the coating mechanism via a flexible web so that an approach or recession (with respect to the moving surface) of the coater bed surface defining in part the accumulator or distribution chamber can be achieved by moving the coater bed as a whole. The adjusting device can support itself on the coater bed as well as on the support element. For the above-described design, which employs a coater rod to serve as a coater, the rod can have a diameter of between 10 and 38 mm, preferably approximately 24 mm, which is advantageous as far as handling is concerned. In a further development of the present invention, at least one section of the adjoining limiting surface can be made flat. In order to achieve an optimum hydrodynamic interaction between the limiting surface and the coater rod, this flat section of the flat limiting surface can be positioned at a distance of up to 1 mm relative to an imaginary plane positioned tangentially to the coater rod and substantially parallel to the flat section of the limiting surface. Additionally, or alternatively, the flat section of the limiting surface can be positioned at an angle of up to 10 degrees relative to an imaginary plane positioned tangentially to the coater rod, allowing a smooth convergence in the accumulator/nip area, and thus avoiding the undesired generation of turbulences in the coating medium. Additionally, or alternatively to the flat surface section, the limiting surface can also include a section which has the shape of a partial outer surface of a circular cylinder. Specifically, this circular cylinder can have a radius of between 10 mm and 600 mm, preferably approximately 50 mm. In order to avoid deposits on the limiting surface, at least a part of the surface sections of the limiting surface can be connected by rounded-off transition sections. As touched upon in a previous section of this text, with a coating mechanism employing a coater rod placed in a cavity of the coater bed in a such a manner that it is allowed to rotate, any changes to the relative position of the limiting surface and moving surface should not affect the support of the coater rod in its seat. This allows an independent adjustment of the coater rod mounting in the rod cavity on one hand and the geometry of the accumulator chamber on the other hand. In order to facilitate a pressing of the coater rod against the moving surface and in order to be able to fix the position of the coater in the coater bed, an additional adjusting mechanism can be provided, which can be activated independently from the above-described adjusting mechanism. The terminology “fixing the position” in this context describes a measure to secure the coater rod to keep it from falling out. Concurrently, though, it must be assured that the rod is still capable of rotating in its bed. In order to respond to possible non-uniformities that remain in the coating, it is suggested that the minimum of one adjusting mechanism includes a plurality of adjusting elements distributed in the transverse direction of the machine, all of which are activated independently from each other. The adjusting elements can be activated in at least one of the following manners: electrically, hydraulically, pneumatically, hydro-pneumatically and manually. An especially simple design of the adjusting mechanism can be achieved when at least part of the adjusting elements have pneumatic hose units. Further, in view of achieving a satisfactory coating profile in the transverse direction, at least one adjusting element can contain a pneumatic hose that includes a plurality of individual pressure chambers. The invention further relates to a process designed to apply a liquid or viscous coating medium onto a moving surface by use of a machine as it is described above. The process allows the coating pressure to be influenced or adjusted by altering the relative position of the limiting surface with respect to the moving surface, that is, by altering the shape or geometry of the accumulator chamber. With respect to the advantages and further development opportunities of this process, reference is made to the aforementioned discussion of the coating mechanism. It should be especially highlighted here that the process, as described by this invention, lends itself to modify or adjust the transverse profile of the coating that is to be applied onto the moving surface by altering the relative position of the limiting surface with respect to the moving surface in specific zones of the application area. BRIEF DESCRIPTION OF THE DRAWINGS The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: FIG. 1 is schematic, partial cross-sectional side view of a coating mechanism in accordance with this invention; and FIG. 1 a is a schematic partial view of a pressure hose with a plurality of individual pressure chambers. FIGS. 2-4 are illustrations in the same fashion as shown in FIG. 1 of additional designs. Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate at least one preferred embodiment of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings and particularly to FIG. 1, there is shown a coating mechanism 10 in accordance with the intent of the present invention. It is serves to apply a layer 12 of coating material 14 of uniform thickness onto a moving surface U traversing in direction L. In this case, moving surface U is outer surface 16 a of a transfer roll 16 . Coating medium 14 is applied in excess, although pre-metered, onto roll 16 by use of a coating applicator (not shown) and receives the final metering as well as final smoothing by use of coater 18 (FIG. 1 ), so that is coating layer 12 receives a uniform thickness in the longitudinal direction L as well as in the transverse direction Q. Coater 18 includes a coater bed 20 , which is fastened to support element 24 of coating machine 10 by support piece 22 (shown only schematically in FIG. 1 ). Coater rod 26 is seated in a cavity 20 a of a base unit 20 b , which is part of coater bed 20 , and rotates around its longitudinal axis A which is essentially located parallel to transverse direction Q. Coater rod 26 , whose outer surface can either be smooth or profiled, can rotate in the opposite direction with respect to the feed direction L of the moving surface U, i.e., in the direction as indicated by arrow P in FIG. 1 . Upstream of coater rod 26 resides a flexible tongue 20 c of base unit 20 b ; both of which are an integral part of the coater bed. The flexibility of the tongue is a function of the material properties of the tongue, as well as a function of certain design features. In the example shown in FIG. 1, tongue 20 c is designed to be relatively slender so the tongue can be pushed against moving surface U by pneumatic pressure hose 28 , given the constraints of the elastic deformation capability of the material of coater bed 20 . When releasing the pressure from the pneumatic pressure hose 28 , the tongue moves away from the moving surface U and returns to its original position as a result of its natural elastic characteristics. Coater rod 26 is supported in such, a manner as to preclude an effect thereon as the pressure in pressure hose 28 fluctuates. One outer surface 20 d of tongue 20 c extends in a direction opposite to the feed direction L of moving surface U to a distance from the coater rod 26 which is specified as D 1 and has a proximity of d 1 relative to the moving surface U. Because of the protruding design of the tongue, an accumulator chamber 30 is formed by the moving surface U and the surface 20 d of tongue 20 c facing the moving surface, in which the coating medium (supplied in excess quantity) accumulates ahead of coater element 26 . Coating medium 14 disperses inside this accumulator chamber 30 in transverse direction Q, so that at any place within the working area, a sufficient amount of coating medium 14 is present at coater element 26 . Additionally, the hydrodynamic pressure present in accumulated coating medium 14 also equalizes across transverse direction Q. The hydrodynamic pressure conditions are thus substantially identical at any point along coater rod 26 , so that metering slot 32 formed by moving surface U and coater rod 26 is substantially uniformly constant across the entire working width, resulting in the desired uniform coating layer 12 . As is known from the state of the art, the width of metering slot 32 is self-adjusting as a result of opposing forces: On one hand, the hydrodynamic pressure present in accumulator chamber 30 attempts to lift coater element 26 including coater bed 20 off from moving surface U. On the other hand, coater rod 26 and coater bed 20 are being forced towards moving surface U by an adjusting mechanism, which is only indicated schematically in FIG. 1 by arrow 34 . Since surface 20 d of tongue 20 c separating accumulator chamber 30 from coater bed 20 is relatively large compared to the outer surface of coater rod 26 facing accumulator chamber 30 , the pressure acting upon surface 20 d , forcing a widening of coating gap 32 , dominates. The entire pressure loading induced by coating medium 14 and acting upon coater bed 20 is, therefore, essentially independent of the diameter of coater rod 26 . This has several advantages: On one hand, coating mechanism 10 can take advantage of coater rods having small diameters as well as of coater rods with large diameters. This means that it is possible to deliver a large amount of coating medium 14 onto moving surface U per unit time with cost-effective, commercially available, easy-to-handle coater rods. Consequently, the pressure acting upon the moving surface U is relatively low. On the other hand, the pressure of coating layer 12 can be altered by simply changing the relative position of limiting surface 20 d with respect to moving surface U, without having to change the force settings of adjusting mechanism 34 , designed to force coater rod 26 against moving surface U. Furthermore, coater 18 requires a reduced number of coater rods with varying diameters to cover the full operating spectrum, compared to traditional coaters, whose hydrodynamic forces attempt to widen metering slot 32 upstream of the coater rod, are largely dependent on the diameter of the coater rod. Length D 1 of accumulator chamber 30 can range between approximately 5 and 100 mm, while a height d 1 of the accumulator chamber can range between approximately 0.5 mm and 5 mm, preferably between 0.5 mm and 2 mm. If moving surface U is moving at a low rate of speed, such as at a speed of approximately 900 m/sec, then a long accumulator chamber 30 with a small inlet width should be selected. For medium feed speeds, i.e., approximately 1000 m/sec, a medium-sized accumulator chamber length with a medium sized inlet width is recommended. For high feed speeds, such as speeds in excess of 1500 m/sec, a short accumulator chamber length with a large-sized inlet width is suggested. It should be mentioned here that pressure hose 28 is supported on base unit 20 b of coater bed 20 for adjusting purposes. As schematically shown in FIG. 1 a , pressure hose 28 can be sectioned into a plurality of individual pressure chambers 28 a , which are independently provided with a pressurized medium such as air via pressure lines 28 b . The sectioning of the pressure hose allows the adjustment of height d 1 of accumulator chamber 30 at various places along the width of the machine, facilitating a transverse profiling of coating 12 . A further advantage of coater 18 can be realized by allowing the thickness of coating 12 to be altered through changing height d 1 of accumulator chamber 12 . This eliminates the need of having to change the feed speed of moving surface U traversing in feed direction L, or of having to change the viscosity of coating medium 14 for the purpose of achieving a different coating thickness. Coater 18 introduces an additional and quick process to alter the thickness of coating 12 . FIG. 2 illustrates another design variation of coating mechanism presented by this invention. It is fundamentally similar to the coater mechanism represented in FIG. 1 . The same parts use the same reference labels as used in FIG. 1 but are increased by the number 100 . It should also be pointed out that the description of coating machine 110 displayed in FIG. 2 is limited to the differences between the two designs. The coater 118 of the design shown in FIG. 2 differs from the coater 18 shown in FIG. 1 mainly by the fact that coater bed 120 of FIG. 2 does not include a tongue 20 c. Web 122 , required to mount the coater bed 120 onto support element 124 , is designed to be sufficiently flexible and is mounted on coater bed 120 in such a manner, that coater bed 120 pivots around an axis parallel to transverse direction Q, as a result of pressure applied to pressure hose 128 which is supported by support element 124 . Coater bed 120 includes a “protruding lip” 120 c , extending in opposite direction of feed direction L, onto which pressure hose 120 acts upon, and whose surface 120 d facing moving surface U together with moving surface U, forms accumulator chamber 130 . Through clever design of coater bed 120 , mounting web 122 , as well as pressure hose 128 , it is feasible to locate the axis, around which coater bed 120 pivots upon applying pressurized gas to pressure hose 128 , to a position which is identical to the position of the axis associated with coater rod 126 . This has the advantage that the width of metering slot 132 does not fundamentally change when altering the geometry of accumulator chamber 130 and has the additional advantage that the adjusting force of adjusting mechanism 134 is not biased in significant ways. FIG. 3 illustrates another design variation of the present invention, which corresponds, in essence, to the designs displayed in FIGS. 1 and 2. The same parts use the same reference labels as used in FIGS. 1 and 2 but are increased by the number 200 , compared to the reference numbers used in FIG. 1 . It should also be pointed out that the description of coating machine 210 displayed in FIG. 3 is limited to the differences between it and the designs shown in FIGS. 1 and 2. Coating mechanism 210 shown in FIG. 3 utilizes coater bed 220 of coater 218 designed and supported in a manner that allows base unit 220 b to be rotated around the axis A of coater rod 226 . To facilitate this motion, gear teeth 220 e are integrated into coater rod bed 220 engaging with gear 228 a of adjusting mechanism 228 . Base unit 220 b of coater bed 220 includes a tongue 220 c designed in a similar fashion to the construction shown in FIG. 1 . Tongue surface 220 d (facing moving surface U) together with moving surface U bounds accumulator chamber 230 . Tongue 220 c does not necessarily have to be designed to be flexible, since a fixed tongue 220 c is just as suitable to be moved to and from moving surface U by use of drive mechanism 228 . In the construction shown in FIG. 3, however, tongue 220 c is designed to be flexible and is mounted by support arrangement 236 onto support element 224 of coating machine 210 . Support arrangement 236 can be attached to support element 224 in a fixed or movable manner. By supporting tongue 220 c of coater bed 220 , tongue 220 undergoes a bending as,it is moved towards moving surface U in response to an adjustment of adjusting mechanism 228 , so that the section of surface 220 d bounding the accumulator chamber comes closer to moving surface U, as compared to a section of surface 220 d that is further removed from metering slot 232 . This can have a favorable impact on the hydrodynamic pressure conditions in accumulator chamber 230 . FIG. 4 illustrates another design variation of the present invention, which corresponds, in essence, to the design displayed in FIG. 2 . The same parts use the same reference labels as used in FIG. 2, but are increased by the number 200 , compared to the reference numbers used in FIG. 2, or increased by the number 300 as compared to the reference numbers used in FIG. 1 . It should also be pointed out that the description of coating machine 310 displayed in FIG. 4 is limited to the differences between it and the designs shown in FIGS. 1 through 3. Coater 318 of coating machine 310 shown in FIG. 4 differs from coating mechanism 118 shown in FIG. 2 only by the addition of a distribution chamber 340 upstream of accumulator chamber 330 , whose taper in direction opposite of the feed direction L is more pronounced as compared to accumulator chamber 330 . For example, distribution chamber 340 can have length D 2 ranging from approximately 5 to 30 mm and an inlet width d 2 ranging from approximately 4 to 11 mm. The wide distribution chamber 340 of the design shown in FIG. 4 serves to evenly distribute coating medium 314 , as well as to distribute the hydrodynamic pressure present in the coating medium in transverse direction Q of moving surface U. Coating medium 314 subsequently passes through narrow accumulator chamber 330 into metering slot 332 , at which point it has a uniform flow pattern, resulting in improved coating quality. Accumulator chamber 330 , as well as distribution chamber 340 , is bound by surface 320 d of coater bed 320 . Surface 230 d includes a first section 320 d 1 , which is part of accumulator chamber 330 , and a second section 320 d 2 , residing closer to pressure hose 328 , which is part of distribution chamber 340 . In order to simplify the design of coating mechanism 310 , as well as to simplify the controls aspect of the adjusting mechanism, the design is such that pressure hose 328 affects the position of both surface sections 320 d 1 and 320 d 2 relative to moving surface U simultaneously. In order that coating medium 314 does not adhere to surface 320 d , the transition between two surface sections 320 d 1 and 320 d 2 is rounded in the area labeled as 320 d 3 instead of being a sharp edge. This design feature should also be applied to other areas of coating machine 310 for similar reasons. Finally, it should be pointed out that limiting surfaces 20 d , 120 d , 220 d and surface section 320 d 1 of all design variations depicted in FIGS. 1 through 4 are flat, at least at their end regions bordering the coater rod. As FIG. 4 shows in form of an example, which is also applicable for the remaining Figures, flat surface section 320 d 1 is positioned at an angle of up to 10 degrees relative to an imaginary plane T 1 located tangentially to moving surface U at metering slot 332 . The resulting, relatively narrow nip of accumulator chamber 330 provides an effective manner in which to distribute and feed coating medium 314 to metering slot 332 . Additionally, this surface section is placed at a distance of no more than 1 mm (distance h) from another imaginary plane T 2 , which is located tangentially to coater rod 326 at metering slot 332 . This means that flat surface section 320 d 1 is nearly tangential to coater rod 326 , so that the outer surface of coater rod 326 and the adjacent flat surface section 320 d 1 form one unit which acts like a coater rod having a large diameter. All this has a favorable impact on the coating quality. Because of the effectiveness of the accumulator chamber, designed per the intent of the present invention, and the adjacent distribution chamber, coater rods of small diameters can be utilized and more coating medium can be applied per unit time. At the same time a uniform coating quality can be achieved. Furthermore, it should be mentioned here that not only can a curved limiting surface be employed, as shown in FIG. 3, but one can also employ a limiting surface designed in accordance to the illustrations in FIGS. 1, 2 and 4 , that is inherently curved. Specifically, the curvature can have a approximate range in radius of between 10 mm and 600 mm, preferably 50 mm. While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
A coating machine serves to directly or indirectly apply a liquid or viscous coating medium onto a moving surface. A coater imbedded in a coater bed, defines in part the metering slot. A limiting surface at the moving surface inlet of the coater bed forms, together with the moving surface, an accumulator chamber, with the opening facing in the opposite direction with respect to the feed direction. The accumulator chamber gradually reduces its volume, and the coating medium, delivered to the accumulator chamber by the moving surface, accumulates in the area ahead of the metering slot. It further includes pneumatic pressure device to alter the relative position of the limiting surface with respect to the moving surface and thus alter the geometry of the accumulator chamber.
3
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to priority control systems for determining rights to bus use for performing direct data transfer between the random access memory (RAM) of an information processor and periphery equipment without using the central processing unit (CPU). 2. Description of the Prior Art For DMA transfer bus interrupts, there are two cases; one in which rights to bus use by the CPU are prioritized in a main group and the other in which a priority order is determined for a subgroup of a requesting source in the main group. A conventional priority control system is shown in FIG. 3. The priority control system includes a CPU 1; a dynamic memory or RAM 2; four input/output (I/O) devices 3; a data bus 4; an address bus 5; and a direct memory access (DMA) controller 7. The DMA controller 7 includes a sampling signal generator 6; a priority circuit 8; a priority encoder 9; an access controller 10; and a DRAM controller 11. The RAM requires periodic refreshing. The priority circuit 8 determines a priority order among bus requests. The priority circuit 8 for performing main sampling is composed of a circuit in which an interrupt priority order is determined by hardware. The priority encoder 9 for determining a priority order among channels of the I/O devices 3 is composed of a circuit for performing auxiliary sampling. For example, the priority encoder 9 has four channel input ports, of which one channel is given priority and outputted as a bus request to a predetermined channel of the priority circuit 8. The I/O devices 3 consist of four circuit periphery devices, for example, which are connected to respective channel input ports of the priority encoder 9. The priority order from top to bottom in the priority circuit 8 is as follows: (1) RAM refreshing request by the DRAM controller 11; (2) HOLD external interrupt request; (3) DRQ bus request by the I/O devices 3; and (4) bus requests by the CPU 1. Consequently, there are a main priority group connected to the priority circuit 8 and a auxiliary priority group within the I/O devices 3 which is one of the inputs to the priority circuit 8. The sampling signal generator 6 outputs a machine cycle basic clock to the priority circuit 8 and a sampling signal 2 having a frequency of a half of the machine cycle to the priority encoder 9. Gates 1-1, 1-2, 10-1, 10-2, 11-1, and 11-2 interconnect the buses 4 and 5 to the respective controllers. DMACK is a response signal to the I/O chip of a bus requesting source, etc. to which priority is given. The operation will be described with reference to FIG. 4. The basic clock φ synchronized with the machine cycle, for example, and the half clock 2φ made by dividing the basic clock by 2 are inputted to the sampling signal generator 6. Consequently, DRQL and DRQH are outputted in synchronism with "H" of φ in the periods "H" and "L" of 2φ, respectively. The DRQL and DRQH are inputted to the priority encoder 9 and the priority circuit 8, respectively. The priority encoder 9 samples DMA requests DRQs from the respective I/O devices in synchronism with the rising edge of DRQL to select a request of the highest priority and outputs it as a bus request BRQ to the priority circuit 8. The priority circuit 8 samples the bus request BRQ, etc. in synchronism with the rising edge of DRQH, accepts the BRQ if there is neither DRAM refreshing request a nor HOLD request b which are given higher priorities than the BRQ, and outputs a BAK signal, turning off the gates 1-1 and 1-2 which have connected the buses 4 and 5 to the CPU 1 and on the gates 10-1 and 10-2 connected to the access controller (DMAC) 10 to start bus control by the DMAC 10. When the DMAC 10 connects the I/O devices 3 and the RAM 2 by bus control, a signal DMACK for selecting a chip to which the highest priority is given by the priority encoder 9 is outputted to a predetermined I/O device 3 for effecting a DMA transfer. However, when the BUSY signal is "H" at the main sampling time DRQH, the DMAC 10 is unable to receive the bus use right so that it must wait until the BUSY signal becomes "L". Consequently, the period between the first sampling at the auxiliary sampling signal DRQL and the time when the DMAC 10 resumes the bus use can be so long as shown by A in FIG. 4 that the information becomes too old; that is, it is not the latest DMA request from another I/O device 3. SUMMARY OF THE INVENTION Accordingly, it is an object of the invention to provide a priority control system capable of monitoring the bus use conditions to use either the main or the auxiliary sampling, thereby not only making constant the period between the auxiliary sample and the start of bus use but also providing a response in the shortest time. According to the invention there is provided a priority control system having a bus, which includes a main group of first bus request sources; an auxiliary group of second bus request sources provided in one of the first bus request sources; a unit for alternating main and auxiliary sampling for checking if there is a bus request for the main or auxiliary group; and a bus use condition detector for detecting use conditions of the bus to select either the main or said auxiliary sampling. When the bus condition detector finds that the bus is not used, only the main sampling is taken of the bus request sources of the main group. By making constant the period between the auxiliary sampling of the auxiliary group and the start of bus use and enabling the DMA controller to immediately accept the bus request which is made by a bus request source in the main group upon completion of the bus use by the auxiliary group, it is possible to transfer the right to bus use to the main group of the higher priority without a waste of time. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a priority control system according to an embodiment of the invention; FIG. 2 a timing chart useful for explaining the operation of the priority control system of FIG. 1; FIG. 3 is a block diagram of a conventional priority control system; and FIG. 4 is a timing chart useful explaining the operation of the priority control system of FIG. 3. DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, the priority control system according to an embodiment of the invention includes a CPU 1; a dynamic memory or RAM 2; four I/O devices 3; a data bus 4; an address bus 5; and a DMA controller 17. The DMA controller 17 includes a priority circuit 8; a priority encoder 9; an access controller 10; a DRAM controller 11; a bus use detector 14; and a sampling signal generator 13. The RAM 2 requires periodic refreshing. The priority circuit 8 determines a priority order among bus requests. The priority circuit 8 for performing main sampling is composed of a circuit in which the interrupt priority order is determined by hardware. The priority encoder 9 determines a priority order among the channels and performs auxiliary sampling. For example, it has 4 channel input ports, of which one channel is given priority and outputted to a predetermined input port of the priority circuit 8 as a bus request by the I/O devices 3. The I/O devices 3 have four periphery devices, for example, which are connected to respective channels of the priority encoder 9. The priority order from top to bottom in the priority circuit 8 is as follows: (1) DRAM refresh request for the RAM; (2) HOLD external interrupt request; (3) BRQ bus request by the I/O devices 3; and (4) bus requests by the CPU 1. Consequently, there is a main priority group connected to the priority circuit 8 and an auxiliary priority group within the I/O devices 3 which is one of the inputs to the priority circuit 8. The bus condition detector 14 detects the use conditions of the buses 4 and 5 based on a bus acknowledge BAK which is outputted to the CPU 1 from the priority circuit 8. The operation will be described with reference to FIG. 2. The bus condition detector 14 monitors the use conditions of the buses 4 and 5 to generate a BUSY signal. In response to the BUSY and the internal clock φ, the sampling signal generator 13 generates DRQL and DRQH. That is, DRQL and DRQH are generated in synchronism with "H" of φ during "H" and "L" of the BUSY, respectively. Since the bus is used during the period T 2 in which the BUSY is "H", the auxiliary group is sampled. The priority encoder 9 samples DMA requests DRQs from the respective I/O devices in synchronism with the rising edge of DRQL to select a request of the highest priority and outputs a bus request BRQ to the priority circuit 8. If the BUSY stays "H" or the bus is continuously in use, the above auxiliary sampling and the prioritizing of the auxiliary group are repeated to update the information. The priority circuit 8 samples the bus request BRQ, etc. in synchronism with the rising edge of DRQH to generate a BAK signal if there is neither DRAM refresh request a nor HOLD request b which have higher priorities than the BRQ, turning off the gate 1-1 and 1-2 which have connected the buses 4 and 5 to the CPU 1 and on the gates 10-1 and 10-2 connected to the DMAC 10 to start bus control by the DMAC 10. Simultaneously, a signal DMACK for selecting a chip to which the highest priority is given by the priority encoder 9 is outputted to the requesting I/O device to effect a DMA transfer. When the BUSY becomes "L" or the bus is not used, the bus request BRQ, etc. are sampled in synchronism with the rising edge of DRQH. Since the sampling timing is synchronized with "L" of the BUSY so that the bus is not used, it is unnecessary for the main sampling to wait until the completion of bus use. In addition, the auxiliary sampling is always taken to update the information during the bus use or when the BUSY is "H" so that the main sampling is taken with the latest information (the prioritizing result of the auxiliary group). It is noted that the invention is applicable to general bus requests as well as the DMA control. As has been described above, the priority control system according to the invention includes a main group of bus request sources, one of which includes an auxiliary group of bus request sources and a bus use condition detector for detecting the bus use conditions to effect either the main or the auxiliary sampling and generating a sampling signal in synchronism with the result so that it is possible to effect the main sampling immediately after the latest auxiliary sampling. In addition, it is possible to respond with the minimum time to the bus request of a bus request source in the main group of the highest priority for the bus use right, thereby enhancing the DMA transfer capability.
A priority control system for determining a priority order of bus requests in an information processor includes a main group of first bus request sources; an auxiliary group of second bus request sources provided in one of the first bus request sources; and a sampling unit responsive to the bus use conditions to effect sampling to check if there is a bus request for either said main or said auxiliary group.
6
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The instant invention relates generally to the production of nonwoven products. More specifically, the instant invention relates to a forming fabric or belt for use in the manufacture of nonwovens. [0003] 2. Background of the Invention [0004] The production of nonwoven products is well known in the art. Nonwoven products are used in a wide variety of applications ranging from baby diapers to high performance textiles where the engineered qualities of the products can be advantageously employed. Numerous nonwoven products can be manufactured using the instant invention including, but not limited to: geotextiles; building materials such as MDF (medium density fiberboard), roofing and tile underlayment, acoustic ceiling tiles and thermal and sound insulation; hygienic and healthcare products such as bandages, tapes, sterile packaging, diapers and sanitary napkins; and household goods such as wipes, scouring pads, fabric softener sheets, placemats, napkins, washcloths, tablecloths and vacuum bags. In these types of products, the fibers or filaments of the product are integrated into a coherent web. Entanglement of the fibrous elements of the nonwoven web, coupled with other processes such as chemical or thermal bonding, provides the desired product integrity, functionality and aesthetics. [0005] Such products are produced directly from fibers without conventional textile methods such as weaving or knitting operations. Instead, they are produced by nonwoven manufacturing methods and processes such as meltblowing. In the meltblown process for manufacturing nonwoven products, a thermoplastic forming polymer is placed in an extruder and is then passed through a linear die containing about twenty to forty small orifices per inch of die width. Convergent streams of hot air rapidly attenuate the extruded polymer steams to form solidifying filaments. The solidifying filaments are subsequently blown by high velocity air onto a take-up screen or another layer of woven or nonwoven material thus forming a meltblown web. [0006] In addition, nonwoven products may be produced by air-laying or carding operations where the web of fibers is consolidated or processed, subsequent to deposition, into a nonwoven product by needling or hydroentanglement. In the latter, high-pressure water jets are directed vertically down onto the nonwoven web to entangle the fibers with each other. In needling, entanglement is achieved mechanically through the use of a reciprocating bed of barbed needles which force fibers on the surface of the web further thereinto during the entry stroke of the needles. [0007] Nonwoven products are generally made up of fibers locked into place by fiber interaction to provide a strong cohesive structure, with or without the need for chemical binders or filament fusing. The products may have a repeating pattern of entangled fiber regions of higher area density (weight per unit area) than the average area density of the product, and interconnecting fibers which extend between the densely entangled regions that are randomly entangled with each other. Localized entangled regions may be interconnected by fibers extending between adjacent entangled regions to define regions of lower area density than that of the adjacent high-density region. A pattern of apertures substantially free from fibers may be defined within or between the dense entangled regions and interconnecting fibers. Unlike in the instant invention, however, these patterns are not used to separate the nonwoven web into a plurality of individual or separate nonwoven sheets. [0008] In some products, the densely entangled regions are arranged in a regular pattern and joined by ordered groups of fibers to provide a nonwoven product having an appearance similar to that of a conventional woven fabric, but in which the fibers proceed randomly through the nonwoven product from entangled region to entangled region. The fibers of an ordered group may be either substantially parallel or randomly disposed relative to one another. Embodiments include nonwoven products having complex fiber structures with entangled fiber regions interconnected by ordered fiber groups located in different thickness zones of the nonwoven, which are particularly suitable for apparel and industrial products such as wipes. [0009] As previously stated, the nonwoven web may be processed and the fibers locked into place in the product by fiber interaction. By “locked into place,” it is meant that individual fibers of the structure not only have no tendency to move from their respective positions in the patterned structure, but they are actually also physically restrained from such movement by interaction with themselves and/or with other fibers of the product. Fibers are locked into place in the entangled fiber regions of higher area density than the average area density of the product, and such fiber interaction may also occur elsewhere. [0010] By “interaction,” it is meant that the fibers turn, wind, twist back-and-forth and pass about one another in all directions of the structure in such an intricate entanglement that they interlock with one another. [0011] Mechanical entanglement processes such as needling, bind or secure a layer or layers of fibers to themselves or to a substrate by impaling the fibrous webs with a large number of barbed needles in a device called a needle loom or fiber locker. This action pushes fibers from the fiber layer surface into and through the bulk of the web layers. While strength properties are improved by this entangling of fibers within the web, the process can be slow, the needles can damage the fibers, and the needles themselves are worn out rapidly. [0012] In order to avoid these problems, hydroentangling (or “spunlacing”) processes have been developed which use the energy of small-diameter, highly coherent jets of high-pressure water to mimic the entangling action of the older needle loom. The process involves forming a fiber web as described above, after which the fibers are entangled by means of very fine water jets under high pressure. Several rows of water jets are directed against the fiber web which is supported by a movable wire or fabric. The entangled fiber web is then dried. The fibers that are used in the material can be synthetic or regenerated staple fibers, e.g. polyester, polyamide, polypropylene, rayon or the like, cellulose or other material fibers or mixtures of any combination of these materials. Spunlace materials can be produced in high quality at a reasonable cost and have a high absorption capacity. They can be used as wiping materials for household or industrial use, as disposable materials in medical care and for hygiene purposes, etc. [0013] The hydroentangling process can be used to produce a large number of different products by varying the initial material and/or the belt/patterning member used. The initial material may consist of any web, mat, batt or the like of loose fibers disposed in random relationship with one another or in any degree of alignment. The term “fiber” as employed herein, is meant to include all types of fibrous material, whether naturally or synthetically produced, and comprises, for example, fibrids (of a type of synthetic fibrous particles used in bonding), cellulose fibers, and textile staple fibers. Improved properties can be obtained by suitable combinations of different lengths of fibers. Reinforced products are provided by combinations of staple length fibers with fibrous strands, where the term “strands” includes filaments and various forms of conventional textile fibers, which may be straight or crimped, and other desirable products are obtained by using highly crimped and/or elastic fibers in the initial material. Particularly desirable patterned, nonwoven products are prepared by using an initial material comprising fibers having a latent ability to elongate, crimp, shrink, or otherwise change in length, and subsequently treating the patterned, nonwoven structure to develop the latent properties of the fibers so as to alter the free-length of the fibers. The initial material may contain different types of fibers, e.g., shrinkable and nonshrinkable fibers, to obtain special effects upon activation of the latent properties of one type of fiber. [0014] In addition, thermal bonding can be used to lock the fibers in the nonwoven product into place. With thermal bonding, a binding material is necessary in order to bind the nonwoven fibers to each other. Binding materials include binding fibers, binding powders and binding webs. Binder fibers are the most widely used in thermal bonding and include single-component and bi-component fibers. When heat is applied, portions of the binder fibers melt, thereby binding with other fibers at the fiber cross-over points. Binding powders in the form of powdered polymers are also used to bind the fibers to each other. The binding powders are applied between layers of fibers during cross-laying, air-laying or as an after treatment. With binding powders, a short exposure to heat in an oven is usually sufficient to melt and fuse the powder to the nonwoven fibers resulting in a nonwoven web comprised of fibers that are bound to each other. Lastly, a binding web, which is a low-melting point, thermoplastic open-structured fabric, can be placed between the nonwoven webs. In order to bind the nonwoven webs together, heat is applied to completely melt the binding web and calendar rolls are used to press and bind the nonwoven webs together. Methods of thermal binding include, for example, hot calendaring, belt calendaring, oven bonding, ultrasonic bonding and radiant heat bonding. The bonding method used has a significant effect on product properties such as porosity, thickness and absorbency. All bonding methods, however, provide strong bond points that are resistant to hostile environments and to many solvents. [0015] In all of the previously described methods and processes used to produce nonwoven products, an endless forming fabric or belt plays a key role in the formation of the nonwoven web. Generally, these belts take the form of mesh screens woven from plastic monofilaments, although metal wire may be used instead of plastic monofilaments when temperature conditions during a nonwoven manufacturing process make it impractical or impossible to use plastic monofilament. [0016] While each of these methods of manufacturing and processing of nonwoven products has its advantages, all current manufacturing systems require additional processing to cut or separate the nonwoven web into the desired sizes and shapes of the final nonwoven product. The instant invention is directed to overcoming this shortcoming of the known systems. SUMMARY OF THE INVENTION [0017] It is therefore a principal object of the invention to provide a forming fabric or belt for use in the manufacture of nonwoven products that reduces post processing of the nonwoven web by eliminating the step of cutting or slitting the nonwoven web into smaller, individual nonwoven sheets. [0018] It is a further object of the invention to provide a forming fabric or belt for use in the manufacture of nonwoven products capable of cutting or dividing the nonwoven web formed thereon during the forming process. [0019] Yet another object of the invention is to provide a forming fabric or belt used in the manufacture of nonwoven products having an impermeable material applied as a coating, an extrusion, a deposition, or as individual strips or pieces of material attached to the surface of the web forming side of the fabric or belt that cuts or slits the nonwoven web into individual, separate nonwoven sheets. [0020] A still further object of the invention is to provide a method of forming a plurality of individual nonwoven sheets on a forming fabric or belt used in the manufacture of nonwoven products. [0021] These and other objects and advantages are provided by the instant invention. In this regard, the instant invention is directed to a forming fabric that is used in the production of nonwoven products. In a preferred embodiment, the forming fabric comprises a plurality of protuberances that are included on the web forming side of the forming fabric. The plurality of protuberances are arranged in a pattern or grid and define the size and shape of nonwoven sheets formed thereon. The protuberances are constructed from an air impermeable material that includes polymeric resins and thermoplastic materials, for example. [0022] Another aspect of the instant invention is a method of forming individual nonwoven sheets. The method includes providing an air permeable forming fabric. A plurality of areas on the web forming surface of the air permeable forming fabric are selectively closed to air in a desired pattern or grid, wherein the desired pattern or grid defines the shape and size of the individual nonwoven sheets formed thereon. Vacuum boxes are provided adjacent to the non-web forming surface of the air permeable forming fabric in order to provide suction to the forming fabric, thereby urging the fibers deposited onto the forming fabric toward the air permeable areas of the fabric. The plurality of areas on the forming belt are rendered impermeable to air by the addition of an impermeable material to the web forming surface of the forming fabric, such as polymeric resins or thermoplastic materials, for example. [0023] The various features of novelty which characterize the invention are pointed out in particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying descriptive matter in which preferred embodiments of the invention are illustrated in the accompanying drawings in which corresponding components are identified by the same reference numerals. BRIEF DESCRIPTION OF THE DRAWINGS [0024] The following detailed description, given by way of example and not intended to limit the present invention solely thereto, will best be appreciated in conjunction with the accompanying drawings, wherein like reference numerals denote like elements and parts, in which: [0025] FIG. 1 is a forming fabric of the instant invention installed on an apparatus used to manufacture nonwoven products; [0026] FIG. 2 depicts a shape and configuration of manufactured nonwoven products, according to one embodiment of the instant invention; and [0027] FIGS. 3A-3E depict various cross-sectional shapes for the impermeable material, according to one embodiment of the instant invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0028] The instant invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the illustrated embodiments set forth herein. Rather, these illustrated embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. [0029] The instant invention relates to a forming fabric or belt used to manufacture slitted or individual nonwoven sheets. As used herein, the terms fabric and belt are used interchangeably. Additionally, the term “web” refers to a nonwoven product formed on a forming fabric. Lastly, a “sheet” as used herein defines any nonwoven product that has dimensions less than the dimensions of the web forming area on the forming fabric upon which it is formed. [0030] Typically, a nonwoven web is formed on a forming fabric and requires additional processing to cut or slit the nonwoven web into smaller, individual sheets. The instant invention eliminates post processing cutting or slitting of the formed nonwoven web since use of the instant forming fabric results in separate, individual nonwoven sheets being formed directly on the fabric during the web forming stage of the manufacturing process. [0031] The instant invention achieves slitted or individualized nonwoven sheets by obtaining a different fiber distribution directly on the forming fabric in, for example, airlaid, meltblown, or spunlace nonwoven manufacturing processes. [0032] As depicted in FIG. 1 , an air permeable forming fabric 10 used in the manufacturing of nonwoven product, having machine direction (MD) and cross machine direction (CD) yarns, such as disclosed in pending U.S. Application entitled “High-Speed Spun-Bond Production of Nonwoven Fabrics” Ser. No. 10/280,865, (U.S. 2003/0164199) the disclosure of which is incorporated herein by reference. The fabric 10 includes an impermeable material 15 in the form of a pattern or grid 20 on the web forming surface 25 of the forming fabric 10 . It should be noted that the fabric may be woven from yarns, fibers, threads, strands or the like, and that the term “yarns” as used herein is meant to collectively refer to all such elements. Furthermore, the yarns may be of a synthetic or natural material such as metal. Additional structures may be used as the forming fabric substrate, for example, an extruded mesh, a knitted fabric, MD or CD yarn arrays, or other structures suitable for the purpose. [0033] The material used to form the pattern or grid 20 on the forming fabric 10 must be impermeable to air. By having areas on the forming fabric 10 that are impermeable to air, fibers that are deposited on the fabric during one of the previously discussed nonwoven manufacturing processes, are drawn by negative airflow or suction created by vacuum boxes located on the non-web forming side of the forming fabric 10 , to the areas of the fabric that are permeable to air. As a result, the fibers that are deposited on the fabric accumulate on the air permeable areas of the fabric and not on the areas of the fabric that have been made impermeable with the addition of the impermeable material. Because the fibers on either side of the air impermeable areas of the fabric are isolated from one another and hence do not interact with each other, these portions of the nonwoven web are prevented from becoming entangled with one another during one of the previously described entangling methods. After the fibers are deposited onto the belt, the fibers are locked into place using one of the previously disclosed processes. The result is a nonwoven web that is already separated or slit into individual nonwoven pieces 30 . [0034] As depicted in FIG. 1 , gaps 35 are formed between the individual nonwoven sheets in the areas that correspond to the areas of the forming fabric 10 that have been rendered impermeable to form the pattern or grid 20 . It should be noted that the impermeable material can be applied to the fabric surface as a coating using any of the methods well known in the art or the material can be deposited via extrusion or the material can be deposited via a process as described in commonly assigned, copending application, U.S. patent application entitled “Method of Fabricating a Belt and a Belt Used to Make Both Tissue and Towels and Nonwoven Articles and Fabrics”, Ser. No. 10/334,211 (U.S. 2004/016601 A1), the contents of which are incorporated herein by reference. The impermeable material can also be applied in the form of strips or pieces of material having various shapes and sizes and that are attached to the web forming side of the fabric using any mechanical attachment means known to those skilled in the art, including, but not limited to coatings, gluing with an adhesive, stitching, melt bonding or with the use of hook and loop type fasteners, i.e. VELCRO®. [0035] In one embodiment of the instant invention, as can be seen in FIG. 2 , the individual nonwoven sheets 34 that are formed using the instant forming fabric are defined by X and Y dimensions. These dimensions define the areas on the fabric between the impermeable material on the surface of the belt. The width of the gaps 35 between the individual nonwoven sheets is dependent on the width of the impermeable material that is attached or applied to the surface of the belt 25 . Therefore, various sizes and shapes of the individual nonwoven sheets, within the dimensions of the forming fabric, can be manufactured by varying the size and/or shape of the pattern or grid formed on the belt surface by the impermeable material. As will be evident to a person of ordinary skill in the art, the individual nonwoven sheets do not have to be square or rectangular but can be any shape as defined by a desired pattern formed by the impermeable material. Additionally, a single belt can be designed to produce a plurality of individual nonwoven sheets having varying shapes and sizes. [0036] In order to ensure that the individual nonwoven sheets are well separated from each other at the forming stage of the manufacturing process, the impermeable material applied to the fabric surface forms a plurality of protuberances (protrusions) on the surface that can have various cross-sectional shapes. The protuberances ensure that the fibers on each side of the protuberances are well separated and are therefore prevented from interacting or becoming entangled with one another. Examples of the various cross-sectional shapes for the protuberances include, but are not limited to: thin, low profile rectangular shapes 40 shown in FIG. 3A ; square shapes 42 having sides 43 of equal lengths as shown in FIG. 3B ; high profile rectangular shapes 45 as depicted in FIG. 3C that have a height 50 equal to the thickness of the fiber layers being deposited on the fabric; and shapes having a cross-sectional profile designed to mechanically separate the fibers of the nonwoven web, such as, but not limited the triangular shape 55 in FIG. 3D ; and a rectangular shape 60 having chamfered corners 40 as depicted in FIG. 3E . Essentially, any shape or material that produces individual nonwoven sheets on the fabric surface can be used to form the protuberances. [0037] It is important that the materials used to construct the protuberances must be impermeable to air. The protuberances may be constructed of a thermoplastic material similar to that disclosed in commonly assigned, copending application, U.S. patent application entitled “Fabric with V-Guides”, Ser. No. 10/631,937 (U.S. 2005/0025935) albeit for a different purpose, the contents of which are incorporated herein by reference, or they can be formed from a polymeric resin material, such as, but not limited to, polyamide, polyester, polyetherketone, polypropylene, polyolefin, polyurethane, polyketone, or polyethylene terephthalate resins. The protuberances may also be constructed using silicone, rubber or a rubber like material. As previously discussed, the protuberances may be in the form of a coating, an extrusion, a material deposition or they can be pre-formed strips or pieces of impermeable material that are mechanically attached to the fabric or formed in a manner as discussed in aforesaid U.S. patent application Ser. No. 10/334,211. In the case of a thermoplastic material, the protuberances may be attached to the fabric by melting of a portion of the protuberance in order to encapsulate a portion of the fabric. [0038] It is important to note that where the impermeable material is applied to the web forming side of the fabric, the corresponding portions on the backside or non-web forming side of the fabric, must not have any surface irregularities due to the addition of the impermeable material as compared to the remainder of the belt. This is because the backside surface of the fabric is in contact with the various rolls and vacuum boxes of the manufacturing apparatus. Therefore, any surface irregularities will adversely affect the fabric's travel through the apparatus and bleed vacuum, which lowers the effectiveness of the airflow system. [0039] Although a preferred embodiment of the present invention and modifications thereof have been described in detail herein, it is to be understood that this invention is not limited to this precise embodiment and modifications, and that other modifications and variations may be effected by one skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.
A forming fabric for use in the production of nonwoven products comprising a plurality of protuberances having a predetermined size and shape, wherein the protuberances are arranged in a pattern that defines a size and shape of nonwoven sheets formed therefrom.
3
This is a continuation of co-pending application Ser. No. 657,967 filed on Oct. 5, 1984, now abandoned. BACKGROUND OF THE INVENTION The invention relates to a needle selection arrangement for a circular knitting machine, the arrangement comprising a selector cam box, selector jacks, intermediate jacks, single butt needles and cam sets for the intermediate jacks and needles. The object of the invention is to provide a selection arrangement providing in each of the working sections or sets the possibility of simultaneously selecting needles in knit positions, tuck positions or welting positions. SUMMARY OF THE INVENTION For the above object, the arrangement of the invention is characterised in that the said intermediate jacks are provided with two butts of different length, a long upper butt for tucking and a short lower butt for jersey knitting, said intermediate jacks being in engagement with the selector jacks. These latter selectively adopt three different angles of tilt, and transmit these angles to the intermediate jacks to determine a like number of positions of the butts thereof, both butts emergent corresponding to the knit position; part of the long butt emergent corresponding to the tuck position and no emergent butt corresponding to the welting position. There are three channels in each set of cams, the upper one of which is for the needle butt, the intermediate one for the long butt and the bottom one for the short butt of the intermediate jack, the intermediate channel being spaced from the lower channel in a distance shorter than the distance between the two butts. BRIEF DESCRIPTION OF THE DRAWINGS Further objects and features of the invention will be disclosed in detail in the following description to be read in conjunction with the accompany illustrative drawings in which: FIG. 1 is a vertical cross section of the cylinder of a circular knitting machine, showing the inventive arrangement of the selection system thereof. FIGS. 2 to 4 inclusive illustrate on a larger scale the different paths followed by the needles and intermediate jacks through the cam channels for the tuck, knit and welting positions, respectively, said paths being illustrated with series of short vertical strokes. FIG. 5 illustrates the momentaneous position at a particular time of both butts of the intermediate jacks and the needle butts superimposed on the cam channels of a cam body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 there is shown the moving ring 1 and, on the fixed body holder 30 of a circular knitting machine, a selector box 2 associated with the corresponding selector jacks 3, the intermediate jacks 4 and the needles 5, disposed in a needle cylinder 6. In the known way, selector cams 7 of the selector box 2 act upon the selector jacks 3 mounted in the cylinder 6 and which rock against the cylinder about a convex curved point 8. At the height of this point, the opposite side is supported by an adjustable pusher 9. Furthermore, the selector jacks 3 are retained by springs 10, are positioned heightwise by springs 11 and are spaced apart by ribs 12. The selector jacks 4 are positioned between upper extensions 3a and 3b of selector jacks 3. Thus, the intermediate jacks 4 follow the rocking or tilting motion of the intermediate jacks 3. However, the intermediate jacks 4 may move logitudinally relative to the selector jacks 3. In turn, the needles 5 are retained by further springs 13 and additional springs 14 individually urge the selector jacks 3 against the springs 10 of the box 2. According to the invention, the intermediate jacks 4 are provided with a short lower butt 15 and a long upper butt 16, while the needles are provided with a single butt 17. The short butt 15 is used for jersey knitting and the long butt 16 is used for tucking. The said butts 15, 16 and 17 follow their own paths defined by the cams 19a, 19b and 19c and 20a, 20b, and 20c of the body 18, a situation shown schematically in FIGS. 2, 3 and 4, in such a way that the movements of such butts are attained from three possible positions provided by the cams 7 of the box 2, duly set for each machine working programme. From the vertical position in the jersey knitting stage, the intermediate jacks 4 gradually tilt to the tuck and welting positions, producing the corresponding paths. The cam body 18 comprises a support holding a number of blocks, in the known form, in which there are housed sets of cams 19a, 19b and 19c, on the one hand, and further cams 20a, 20b, 20c and 20d on the other hand, forming respective columns, with the corresponding holding screws 21 and nuts 22 which, with the corresponding grooves define the channels for the butts 15, 16 and 17. As far as the grooves for the butts 15 and 16 of the intermediate jacks 4 are concerned, the distance D between the lower edges of said butts is greater than the distance d between the respective grooves. In this way, FIG. 3 illustrates the knitting operation, comprising the participation of both butts 15 and 16 of an intermediate jack 4, plus the butt 17 of a needle 5, butt 15 being the operative one, wherein the selector jack 3 has been urged to the knit position by spring 14, i.e. is in the vertical position as shown in FIG. 1, and butts 15 engage cams 19c. In view of this, said butt 15 runs up the cam 19c to the peak and then down the other side, whereby butt 16 follows a similar path but spaced apart from cam 19b, while butt 17 of the needle 5 follows the same upward path pushed by the intermediate jack 4 to the maximum rise position. During this part of the movement, the cam 19a acts as a countercam, engaging the butt 17 and limiting the upward movement of the needle 5, thereby preventing the needle from experiencing excessive upward movement. The drawdown movement of the needle-intermediate jack unit is controlled by the cam 20a which engages the butt of the needle and the needle acts on the jack. In this part of the movement, the cams 20b, 20c and 20d act as countercams to prevent the needle of jack from descending too far. FIG. 2 illustrates the tucking movements, with the participation of the butt 16 of the intermediate jack 4 and butt 17 of the needle 5, butt 16 being the operative one, wherein the selector jack 3 is tilted away from vertical position so that the short lower butt 15 does not engage cam 19c. However, part of the long upper butt does engage cam 19b. In this case, said butt 16 follows its channel marked by cam 19b up which it rises, causing the butt 17 of the needle 5 to follow a like movement to that of the butt 16, without it engaging cam 19a, until it engages cam 20a, from which time this cam marks the drawdown path combined with the cam 20b to maintain contact with the first cam 20a. In this case, the butt 15 of the jack 4 passes in front of the cams without making contact therewith. FIG. 4 illustrates the welting position. The selector jack 3 is in the tilted position most removed from vertical so that neither upper butt 16 nor lower butt 15 engage cams 19b and 19c. Thus, the butts of the intermediate jack 4 are not operative, causing the needle butt 17 to move unaffected by the cams along a straight line and the needle to welt, at the same time that the butts 15 and 16 of the said jack 4 pass in front of the faces of the cams without making contact with the cams. FIG. 5 shows, as stated hereinbefore, the momentaneous position of the short lower butt 15 and of the long upper butt 16 of the intermediate jacks and of the butt 17 of the needle 5, shown superimposed on the cam body 18. The butts 17 are comprised in section A, the butts 16 in section B and the butts 15 in section C and are respectively in each of the lines a-u which represent the jack-needle units that are over the said cam body 18 at the time considered. As may be seen, lines c, d, g, n, o and r correspond to welting needles; line f corresponds to a tucking needle; lines e, p and q, correspond to the knitting position (e.g. jersey knitting); lines j, k, t and u correspond to jack-needle units in the selection area; lines h, i and s correspond to jack-needle units in the drawdown stage after knitting or tucking and lines a, b, l and m correspond to jack-needle units rising along the common channel for knitting or tucking. In view of the above, the three types of needle 5 operation are achieved with the new arrangement of selection described with the use of a single intermediate jack for each needle.
A needle selector arrangement in a circular knitting machine, which in each of the working sections or sets allows the needles to be selected simultaneously to knit, tuck or welt. It is provided with cam sets in association with intermediate jacks having a long upper butt and a short lower butt and said intermediate jacks are adapted to assume three different positions, one in which both butts emerge, corresponding to the jersey knitting stage, another in which only part of the long butt emerges corresponding to the tucking stage and a third position in which no butt emerges, corresponding to the welting stage.
3
FIELD OF THE INVENTION [0001] The present invention relates generally to a device for solving linear equations, and more particularly to a parallel device for solving linear equations over finite fields. BACKGROUND OF THE INVENTION [0002] Finite fields are fields containing only a finite number of elements, and linear equations over finite fields are equations of which each factor is an element in finite fields. Finding solutions to linear equations over finite fields is widely used in various engineering fields, such as the field of cryptography, and also the field of solving other mathematical problems. [0003] Methods adopted in solving linear equations include Gaussian elimination method and Gauss-Jordan method. By Gaussian elimination method, linear equations are multi-iterated into upper or lower triangular forms, wherein each iteration operation includes three sub-operations: finding pivot, normalization and elimination. If the equations are solvable, then the final solutions are obtained by substitution operation. Gauss-Jordan method, a variant of Gaussian elimination method, is able to solve linear equations by multiple iterations, but it consumes more resources than Gaussian elimination method. [0004] Solving linear equations is a highly computationally complex and time-consuming issue. At present, there is still large room for optimization of solving linear equations, especially for optimization of those over finite fields. So far, devices dedicated to solving linear equations over finite fields have not yet been reported. SUMMARY OF THE INVENTION [0005] Therefore, in order to address the deficiencies and inadequacies in the art, the present invention aims to provide a parallel device for solving linear equations over finite fields. [0006] The object of the invention is achieved by the following technical solutions. [0007] A parallel device for solving linear equations over finite fields, including: [0008] an input port for inputting coefficient matrix B of linear equations over finite fields and irreducible polynomial p(x) selected over the field GF(2 n ); the coefficient matrix B is an m×(m+1) matrix; the element a(x) of the coefficient matrix B is an element in the field GF(2 n ); [0009] a first processor, including a scheduler and a memory interconnected with each other; the scheduler is configured to control a pivot finding component, a partial inversion component, a normalization component and an elimination component; the memory is configured to store the inputted coefficient matrix B, and to update the stored coefficient matrix B after each iteration operation; [0010] a pivot finding component, including a second processor for finding out the pivot β of the coefficient matrix B; [0011] a partial inversion component, including a third processor for implementing partial inversion calculation; [0012] a normalization component, including a fourth processor and m+1 normalization calculation units; the fourth processor is connected to each of the m+1 normalization calculation units to perform scheduling of the normalization calculation units; [0013] an elimination component, including a fifth processor and m×(m+1) elimination calculation units; the fifth processor is connected to each of the m×(m+1) elimination calculation units to perform scheduling of the elimination calculation units and data transmission; [0014] an output port for outputting the results of linear equations over finite fields being solved, [0015] wherein the first processor is connected to the pivot finding component, the partial inversion component, the normalization component, the elimination component, and the input port and the output port; the partial inversion component is connected to the elimination component and the normalization component; [0016] wherein the first processor receives the coefficient matrix B and the irreducible polynomial p(x) which is selected over the field GF(2 n ) and outputted from the input port, stores the coefficient matrix B into the memory, sets the counter at m, and sends the column containing the pivot to be found in present iteration process to the pivot finding component; the column containing the pivot to be found in present iteration process is set so that in the g th iteration process, the column containing the pivot to be found is the g th column, 0≦g≦m; [0017] wherein the pivot finding component implements a process of finding the pivot: determining whether an element with a row number of g and a column number of g is a none-zero element; if yes, this element is determined to be a pivot, and the pivot finding component sends no back feed into the first processor; [0018] if not, then finding none-zero elements one by one among the elements with row numbers of g+1 to m and a column number of g; the first none-zero element found is determined to be the pivot β, and the pivot finding component sends the row number of the pivot as feedback to the processor; [0019] the first processor sends the pivot β found to the partial inversion component, and sends the row where the pivot β is in to the normalization component, and sends the other lines of the input coefficient matrix B to the elimination component; [0020] the partial inversion component implements partial inversion calculation, and outputs the calculated results to the normalization component and the elimination component; [0021] the normalization component and the elimination component implement the normalization calculation and the elimination calculation respectively, and output the calculated results to the first processor; [0022] the first processor updates the coefficient matrix B according to the results of the normalization calculation and the elimination calculation, stores the updated coefficient matrix B into the memory, subtracts 1 from the value of the counter, and sets the present counter as j; a next iteration is implemented until the counter reaches 0; [0023] if the counter is 0, then outputting the last column of the updated coefficient matrix B into the port as the solved results. [0024] The normalization calculation units are logical gate circuits. [0025] The elimination calculation units are logical gate circuits. [0026] The partial inversion calculation specifically includes: [0027] for i=1, . . . , n−1, the third processor calculates β 2 i ; [0028] let i′=(n−1)÷3, for k=0, 1, . . . , i′−1, calculating S k =MUL3(β 2 3k+1 , β 2 3k+2 , β 2 3k+3 ); MUL3 is the multiplication of three operands defined over GF(2 n ); [0029] outputting β 2 i and S k respectively to the normalization component and the elimination component, and h=3i′+1, 3i′+2 . . . n−1. [0030] The normalization calculation specifically includes: [0031] the l th normalization calculation unit calculates [0000] S i ′ = a tl × ∏ k = 3  i ′ + 1 n - 1  β 2 k , [0000] wherein i=(n−1)÷3, and a t1 is the element in row t and column l of the coefficient matrix B; t is the row where the pivot of the present iteration is in; then calculating [0000] a tl = ∏ q = 0 i ′  S q , [0000] wherein l=0, 1, 2, . . . , m. [0032] The elimination calculation specifically includes: [0033] the elimination calculation unit numbered (k′, l) calculates [0000] S i ′ + 1 = { a k ′  t × a tl × ∏ l = 3  i ′ + 1 n - 1  β 2 l , j ′ < 2 α tl × ∏ l = 3  i ′ + 1 n - 1  β 2 l , j ′ = 2 } , [0000] wherein i′=(n−1)÷3, j′=(n−1)mod 3, and mod represents modular operation; [0034] then calculating [0000] a k ′  l = { S i ′ + 1 × ∏ q = 0 i ′ - 1  S q + a k ′  l , j ′ < 2 a k ′  t × S i ′ + 1 × ∏ q = 0 i ′ - 1  S q + a k ′  l , j ′ = 2 } , [0000] wherein k′=0, 1, 2, . . . , m−1; l=0, 1, 2, . . . , m. [0035] The irreducible polynomial p(x) selected over the field GF(2 n ) has the following form: [0000] p ( x )= x n +p n−1 x n−1 +p n−2 x n−2 + . . . +p 1 x+ 1. [0036] The element a(x) of the coefficient matrix B has the following form: [0000] a ( x )= a n 1 x n 1 +a n 2 x n 2 + . . . +a 0 . [0037] Compared with the prior art, the present invention has the following advantages and technical effects. [0038] By setting independent pivot finding component, partial inversion component, normalization component and elimination component, the present invention realizes parallel computing to a certain extent. The parallel device for solving linear equations over finite fields of the present invention is fast in solving, and simple in design; the partial inversion component, normalization component and elimination component, as well as the solving device for linear equations and other computing devices over finite fields can be widely used in various engineering fields, especially in the hardware implementation of cryptographic algorithms and in solving a variety of mathematical problems. BRIEF DESCRIPTION OF THE DRAWINGS [0039] FIG. 1 is a schematic structure chart of the parallel device for solving linear equations over finite fields in one embodiment of the present invention; [0040] FIG. 2 is a schematic structure chart of the processor in one embodiment of the present invention; [0041] FIG. 3 is a schematic structure chart of the pivot finding component in one embodiment of the present invention; [0042] FIG. 4 is a schematic structure chart of the partial inversion component in one embodiment of the present invention; [0043] FIG. 5 is a schematic structure chart of the normalization component in one embodiment of the present invention; and [0044] FIG. 6 is a schematic structure chart of the elimination component in one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION [0045] The invention will be better understood with reference to the following description taken in conjunction with the specific embodiments and the accompanying drawings. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein. EXAMPLES [0046] As illustrated in FIG. 1 , the parallel device for solving linear equations over finite fields of the embodiment includes input ports, a first processor, a pivot finding component, a partial inversion component and an output port; the first processor is connected respectively to the pivot finding component, the partial inversion component, the normalization component, the elimination component, the input port and the output port; the partial inversion component is connected respectively to the elimination component and the normalization component. [0047] The following is a detailed description of the components of the parallel device of the embodiment. [0048] (1) The input ports: as illustrated in FIG. 1 , there are two input ports in the parallel device of the embodiment of the invention, wherein input port P is configured to input the irreducible polynomial p(x) selected over the field GF(2 n ); input port A is configured to input the coefficient matrix B of the linear equations to be solved. [0049] The coefficient matrix B is a m×(m+1) matrix, and a(x) is an element of the coefficient matrix B; a(x) and p(x) can be in the form of: [0000] a ( x )= a n 1 x n 1 +a n 2 x n 2 + . . . +a 0 ; [0000] p ( x )= x n +p n−1 x n−1 +p n−2 x n−2 + . . . +p 1 x+ 1; [0000] wherein a n−1 , a n−2 , . . . , a 0 and p n−1 , p n−2 , . . . , p 1 are elements in GF(2). [0050] (2) The first processor: as the only component that can communicate with I/O port, the first processor is a core component of the device of the present invention, which can control the pivot finding component, the partial inversion component, the normalization component and the elimination component. [0051] As illustrated in FIG. 2 , the first processor includes a scheduler and a memory interconnected with each other; the scheduler is configured to control the pivot finding component, the partial inversion component, the normalization component and the elimination component; the memory is configured to store the inputted coefficient matrix B, and to update the stored coefficient matrix B after each iteration operation. [0052] (3) The pivot finding component, as illustrated in FIG. 3 , includes a second processor for finding out the pivot β of the coefficient matrix B. [0053] (4) The partial inversion component, as illustrated in FIG. 4 , includes a third processor for implementing partial inversion calculation of the pivot. [0054] (5) The normalization component, as illustrated in FIG. 5 , includes a fourth processor and m+1 normalization calculation units d 0 , d 2 . . . d m ; the fourth processor is connected respectively to the m+1 normalization calculation units to perform scheduling of the normalization calculation units; the normalization calculation units are logical gate circuits. [0055] (6) The elimination component, as illustrated in FIG. 6 , includes a fifth processor and m×(m+1) elimination calculation units c 0, 0 , c 0, 1 . . . c m−1, m−1 , the fifth processor is connected respectively to the m×(m+1) elimination calculation units to perform scheduling of elimination calculation units and data transmission; the elimination calculation units are logical gate circuits. [0056] (7) The output port: as illustrated in FIG. 1 , the output port V is configured to output the calculated results of linear equations over finite fields being solved. [0057] Working process of the parallel device for solving the linear equations over finite fields of this embodiment is as follows: [0058] the first processor receives the coefficient matrix B and the irreducible polynomial p(x) which is selected over the field GF(2 n ) and outputted from the input port, stores the coefficient matrix B into the memory, sets the counter as m, and sends the column containing the pivot to be found in present iteration process to the pivot finding component; the column containing the pivot to be found in present iteration process is set that: in the g th iteration process, the column containing the pivot to be found is the g th column, 0≦g≦m; [0059] the pivot finding component implements the operation of finding the pivot: determining whether an element with the row number of g and column number of g is a none-zero element; if yes, this element is determined to be the pivot, and the pivot finding component sends no back feed to the first processor; [0060] if not, then finding none-zero elements one by one among the elements with the row numbers of g+1 to m and the column number of g; the first none-zero element found is determined to be the pivot, and the pivot finding component sends the row number of the pivot as feedback to the processor; [0061] the first processor sends the pivot found to the partial inversion component, and sends the row where the pivot is in to the normalization component, and sends the other lines of the input coefficient matrix B to the elimination component; [0062] the partial inversion component implements partial inversion calculation, and outputs the calculated results to the normalization component and the elimination component; the partial inversion calculation specifically includes: [0063] for i=1, . . . , n−1, the third processor calculates ⊕ 2 i ; [0064] let i′=(n−1)÷3, for k=0, 1, . . . , i′−1, calculating S k =MUL3(β 3k+1 , β 2 3k+2 , β 2 3k+1 ); MUL3 is the multiplication of three operands defined over GF(2 n ); [0065] outputting β 2 i and S k respectively to the normalization component and the elimination component by the partial inversion component, h=3i′+1, 3i′+2 . . . n−1. [0066] The normalization component and the elimination component respectively implement the normalization calculation and the elimination calculation, and output the results to the first processor; [0067] the normalization calculation specifically includes: [0068] l th normalization calculation unit calculates [0000] S i ′ = a tl × ∏ k = 3  i ′ + 1 n - 1  β 2 k , [0000] wherein i=(n−1)÷3, and a t1 is the element in row t and column l of the coefficient matrix; t is the row where the pivot of the present iteration is in; then calculating [0000] a tl = ∏ q = 0 i ′  S q , [0000] wherein l=0, 1, 2, . . . , m. [0069] The elimination calculation specifically includes: [0070] the elimination calculation unit numbered (k′, l) calculates [0000] S i ′ + 1 = { a k ′  t × a tl × ∏ l = 3  i ′ + 1 n - 1  β 2 l , j ′ < 2 α tl × ∏ l = 3  i ′ + 1 n - 1  β 2 l , j ′ = 2 } , [0000] wherein i′=(n−1)÷3, j′=(n−1)mod3; and [0071] then calculates [0000] a k ′  l = { S i ′ + 1 × ∏ q = 0 i ′ - 1  S q + a k ′  l , j ′ < 2 a k ′  t × S i ′ + 1 × ∏ q = 0 i ′ - 1  S q + a k ′  l , j ′ = 2 } , [0000] wherein k′=0, 1, 2, . . . , m−1; l=0, 1, 2, . . . , m. [0072] The first processor updates the coefficient matrix B according to the calculated results of the normalization calculation and the elimination calculation, stores the updated coefficient matrix B into the memory, subtracts 1 from the value of the counter, and sets the present counter as j; then a next iteration is implemented until the counter reaches 0; [0073] if the counter is 0, then outputting the last column of the updated coefficient matrix B into the port as the solved results. [0074] Working procedure of the parallel device of the present invention is now further described taking the example of n=8 and m=12 (i.e. solving a 12×13 coefficient matrix over finite field GF(2 8 )). [0075] (1) The first processor receives a 12×13 coefficient matrix B and the irreducible polynomial p(x) which is selected over the field GF(2 n ) and outputted from the input port. [0076] Elements a(x) and p(x) of the coefficient matrix B have the following forms, respectively: [0000] a ( x )= a 7 x 7 +a 6 x 6 + . . . +a 0 ; [0000] p ( x )= x 8 +p 7 x 7 +p 6 x 6 + . . . +p 1 x+ 1; [0000] wherein a 7 , a 6 , . . . , a 0 and p 7 , p 6 , . . . , p 1 are elements in the field GF(2 n ). [0077] (2) The first processor stores the coefficient matrix B into the memory, determines the size of the coefficient matrix B to be 12×13, and sets the counter of the built-in calculator as 12; the processor sends the column (the 1 st column) containing the pivot to be found in the first iteration process to the pivot finding component, and waits for feedback of the pivot finding component. [0078] (3) The pivot finding component firstly determines whether the element in first row and first column is a non-zero element. If yes, then this element is determined as the pivot, and the pivot finding component does not send any feedback to the first processor. If not, then finding none-zero elements one by one among the elements with row numbers of 2 to 12, and column number of 1; the finding process stops until a first non-zero element is found. The first none-zero element found is determined as the pivot, and the pivot finding component sends the row number of the pivot as feedback to the processor. [0079] (4) The first processor sends the pivot found in step (3) to the partial inversion component, and sends the row where the pivot is in to the normalization component, and sends the other lines of the input coefficient matrix B to the elimination component. [0080] (5) The partial inversion component implements partial inversion calculation: [0081] The pivot β is an element in the field GF(2 8 ); p(x) is an irreducible polynomial inputted to a selected field GF(2 n ); for i=1, . . . , 7, calculating β 2′ ; [0082] and for k=0, 1, calculating S k =MUL3(β 2 3k+1 , β 2 3k+2 , β 2 3k+3 ); MUL3 is the multiplication of three operands defined over GF(2 n ); [0083] finally, for k=0,1, outputting β 2 7 and S k to the normalization component and the elimination component. [0084] (6) The normalization component receives the row where the pivot is in and data from the partial inversion component, and sends them to each normalization calculation unit. [0085] The l th normalization calculation unit calculates [0000] S i ′ = a tl × ∏ k = 3  i ′ + 1 n - 1  β 2 k , [0000] wherein i′=(n−1)+3, and a t1 is the element in row t and column l of the coefficient matrix B; t=1 is the row number of the pivot of the present iteration; then calculating [0000] a tl = ∏ q = 0 i ′  S q , [0000] wherein l=0, 1, . . . , 12; [0086] the normalization results are outputted to the first processor. [0087] (7) The elimination component receives data from the processor and data from the partial inversion component, and sends them to each elimination calculation unit. [0088] The elimination calculation unit numbered (k′, l) calculates S t′+1 =a k′t ×a t1 ×β 2 7 , wherein t=1; [0089] and calculates [0000] a k ′  l = S 3 × ∏ q = 0 1  S q + a k ′  l , [0000] wherein l=0, 1, . . . , 12, k′=0, 1, 2, . . . , 11; [0090] the normalization results are outputted to the first processor, and the column number of the pivot of the next iteration (the 2 nd column) is outputted to the pivot finding component; [0091] the pivot finding component receives elements in the column of the pivot of the next iteration, implements the operation of finding the pivot, and notifies the first processor to receive data from the normalization component and the elimination component. [0092] Upon receiving feedback from the pivot finding component, the processor subtracts 1 from the counter, receives data from the elimination component and the normalization component, stores the data into the memory, and performs a next iteration. After performing 12 times iteration operation in total and the counter returning to 0, the whole solving process is done. The solved results (last column of the coefficient matrix) are then outputted to the output port. [0093] The above embodiments are preferred embodiments of the present invention, which, however, is not intended to limit the implementation of the present invention. All of the variations, modifications, alternatives, combinations, simplifications that are not apart from the spirit of the invention shall be deemed as equivalences to those skilled in the art, and are within the protection scope of the present invention.
The present invention relates to a parallel device for solving linear equations over finite fields, including a processor, an input port, an output port, a pivot finding component, a partial inversion component, a normalization component and an elimination component. The processor is connected to each of the pivot finding component, the partial inversion component, the normalization component, the elimination component, and the input port and the output port. The partial inversion component is connected to the elimination component and the normalization component. The pivot finding component is connected to the elimination component. The present invention enables parallel computing to a certain extent with fast solving speed and simple design, and thus can be widely used in various engineering fields.
6
[0001] This application is a continuation application of U.S. application Ser. No. 11/427,565, filed Jun. 29, 2006, which is a continuation of U.S. application Ser. No. 10/747,959, filed Dec. 31, 2003. BACKGROUND OF THE INVENTION [0002] The invention relates to an optical substrate with modulated structures on its surface. The optical substrate can be a light modulating substrate of a flat panel display backlight, such as a liquid crystal display (LCD) backlight. [0003] A backlight illuminates a liquid crystal based display panel to provide a uniformly intense light distribution over the entire plane of the LCD display panel. A backlight system typically incorporates a light pipe to couple light energy from a light source to the LCD panel. An array of diffusing elements can be disposed along one surface of the light pipe to scatter incident light rays toward an output plane. The output plane couples the light rays into and through the LCD panel. The backlight can use a light modulating optical substrate with prismatic or textured structures to direct light along a viewing axis, usually normal to the display and to spread illumination over a viewer space. The backlight can use a plurality of optical substrates, stacked and arranged so that the prismatic or textured surfaces are perpendicular to one another and are sandwiched between optical modifying films known as diffusers. The brightness enhancement optical substrate and diffuser film combinations enhance the brightness of the light viewed by a user and reduce the display power required to produce a target illumination level. [0004] It may be advantageous to modulate the structural order of an optical substrate to hide manufacturing defects and to decrease optical coupling interference such as Moiré interference. For example, copending patent application Ser. No. 10/248,099, filed Dec. 18, 2002 discloses modulating a prism structure of an optical substrate from a nominal linear path in a lateral direction (direction perpendicular to the height) by applying a nonrandom, random (or pseudo random) amplitude and period texture. The disclosure of application Ser. No. 10/248,099 is incorporated herein by reference in its entirety. Application Ser. No. 10/248,099 discloses a method which reduces interference Moiré effects. However, for a given nominal texture pitch, a peak to valley depth of the structures which have been modulated is approximately 100% greater than for the un-modulated structure of the same pitch. The greater peak to valley depth for the modulated structures may require a greater overall device thickness to preserve mechanical integrity. The nominal texture pitch is the center to center distance between adjacent structures, such as prisms, on the substrate, the peak to valley depth is the difference between peak and valley. [0005] There is a need for an optical structure on light managed substrate with reduced interference and with preserved mechanical integrity. SUMMARY OF THE INVENTION [0006] According to one embodiment of the invention there is provided an optical substrate. The optical substrate comprises at least one surface, said at least one surface comprising at least one optical structure having a shape and dimensions, wherein the shape and dimensions of each optical structure represents in part a modulation of a corresponding idealized structure, and wherein said shape and dimensions of each of said at least one optical structure is determined in part by at least one randomly generated component of modulation wherein the modulation of each of said at least one optical structure is limited by a neighboring optical structure comprised by the surface. [0007] According to one aspect of this embodiment, the at least one optical structure represents an idealized prismatic structure following a surface path modulated by a mathematical function (1) y i =A i sin {φλ−Φ i }+S i   (1) defined relative to a segment C of a coordinate system, wherein i is an integer indicative of the i th surface path, y i is an instantaneous displacement of the path relative to C on the i th path, A i is an amplitude scaling factor of the i th path relative to C, S i is a shift in a starting position of y i , φ is a number between zero and 2π inclusive, λ is a wavelength which is a real number, Φ i is a phase component for the i th path, wherein Φ i =Φ i−1 +Q i Δ+R i δ  (2) where Q i is randomly or pseudo randomly chosen number having a value of 1 or −1 and R i is a continuous random variable between −1 and 1, each defined for the i th path, where Δ and δ are real numbers that define a magnitude of a phase stepping component and a magnitude of a phase dither component, respectively. [0008] According to another aspect of this embodiment, the at least one optical structure represents an idealized prismatic structure following a surface path modulated by a mathematical function (3a) y i = ∑ k = 1 n ⁢ A i , k ⁢ sin ⁢ { ϕλ k - Φ i , k } + S i ( 3 ⁢ a ) defined relative to a segment C of a coordinate system, wherein i is an integer indicative of the i th surface path, y i is an instantaneous displacement of the path relative to C on the i th path, A i,k is the k th amplitude scaling factor of the i th path relative to C, and S i is a shift in a starting position of y i , φ is a number between zero and 2π inclusive, where n is an integer greater than 1, each wavelength λ k is a real number, Φ i,k is the k th phase component of the i th path, wherein Φ i,k =Φ i−1,k +Q i,k Δ+R i,k δ  (3b) Q i,k is the k th randomly or pseudo randomly chosen number having a value of 1 or −1 for the i th path, R i,k is the k th continuous random variable having a value between −1 and 1 for the i th path, and Δ and δ are real numbers that define a magnitude of a phase stepping component and a magnitude of a phase dither component, respectively. [0009] According to another aspect of this embodiment, the at least one optical structure represents an idealized prismatic structure following a surface path modulated by a mathematical function (4a) y i = ∑ k = 1 n ⁢ A i , k ⁢ sin ⁢ { ϕλ k - Φ i , k } + S i ( 4 ⁢ a ) wherein ƒ is a periodic function defined relative to a segment C of a coordinate system, wherein i is an integer indicative of the i th surface path, y i is an instantaneous displacement of the path relative to C on the i th path, A i,k is the k th amplitude scaling factor of the i th path relative to C, and S i is a shift in a starting position of y i , φ is a number between zero and 2π inclusive, where n is an integer greater than 1, each wavelength λ k is a real number, Φ i,k is the k th phase component of the i th path, wherein Φ i,k =Φ i−1,k +Q i,k Δ+R i,k δ  (4b) Q i,k is the k th randomly or pseudo randomly chosen number having a value of 1 or −1 for the i th path, R i,k is the k th continuous random variable having a value between −1 and 1 for the i th path, and Δ and δ are real numbers that define a magnitude of a phase stepping component and a magnitude of a phase dither component, respectively. [0010] According to another aspect of this embodiment, the at least one optical structure represents an idealized prismatic structure following a surface path modulated by a mathematical function y i =A i [(1 −m ) r i (φ)+ m r i−1 (φ)]+ S i wherein i and i−1 are indicative of an i th and a (i−1) th path, respectively, the i th and the (i−1) th paths being adjacent paths, the i th and the (i−1) th path amplitudes being mixed, wherein part of a random vector for y i−1 is added to y i for the i th path, wherein r i (φ) is a band-limited random or pseudo random function of φ for each i th path, r i (φ) having a continuously varying value between −1 and 1; φis 0 to 2π inclusive; m is a scalar mixing parameter with a value between 0 and 1; A i is an amplitude scaling parameter; and S i is a shift in a starting position of y i . [0011] According to another embodiment of the invention there is provided a backlight display device. The backlight display device comprises: a light source for generating light; a light guide for guiding the light therealong including a reflective surface for reflecting the light out of the light guide; and an optical film. The optical film comprises: at least one surface, the at least one surface comprising at least one optical structure having a shape and dimensions, wherein the shape and dimensions of each optical structure represents in part a modulation of a corresponding idealized structure, and wherein said shape and dimensions of each of said at least one optical structure is determined in part by at least one randomly generated component of modulation wherein the modulation of each of said at least one optical structure is limited by a neighboring optical structure comprised by the surface. BRIEF DESCRIPTION OF THE DRAWINGS [0012] FIG. 1 is a three dimensional view of a backlight display device; [0013] FIG. 2 is a flow chart showing a method of machining a surface of a workpiece wherein the workpiece is a master drum; [0014] FIG. 3 is a flow chart showing a method of machining a surface of a workpiece wherein the workpiece is on a master plate; [0015] FIG. 4 is a diagram of a master drum having a random or pseudo random pattern therein following a generally spiral-like or threaded path; [0016] FIG. 5 is a diagram of a master drum having a random or pseudo random pattern therein over generally concentric paths; [0017] FIG. 6 is a diagram of a master plate having a random or pseudo random pattern therein following a generally sawtooth or triangular path; [0018] FIG. 7 is a diagram of a master plate having a random or pseudo random pattern therein along a series of paths; [0019] FIG. 8 is a diagram of a cross section of a cutting tool in the nature of a prismatic structure; [0020] FIG. 9 is a diagram of the prismatic cutting tool of FIG. 8 having compound angled facets; [0021] FIG. 10 is a graphical representation of the magnitude of the power spectral density of the randomized surface of the workpiece as a function of spatial frequency; [0022] FIG. 11 is a top view of a randomized surface of a workpiece according to an embodiment of the invention; [0023] FIG. 12 is a graphical representation of a plurality of paths due to a plurality of cutting passes over the surface of the workpiece; [0024] FIG. 13 is a schematic representation of a system and apparatus for machining the surface of a work piece in communication over a communications or data network with remote locations; [0025] FIG. 14 is a graphical representation of mathematical functions; [0026] FIG. 15 is a schematic diagram of a master machining system with a fast tool servo for cutting grooves having lateral variations in the surface of a workpiece; [0027] FIG. 16 is a depiction of a cutting gradient introduced into the surface of the machined surface of the workpiece [0028] FIG. 17 and FIG. 18 are graphs of slide feed distance to circumference distance; [0029] FIG. 19 is a surface height map; [0030] FIG. 20 is an autocorrelation of the FIG. 19 surface; and [0031] FIG. 21 is a surface height (depth) histogram. DETAILED DESCRIPTION OF THE INVENTION [0032] According to one aspect of the invention, a phase step limited modulation algorithm may be applied to modulate a regular function of the structure of an optical structure so as to provide an optical structure with a modulated structure. The resulting optical structure can comprise a randomly modulated optical structure defined by a modulation algorithm that modulates a parameter of the regular function, such as the phase, although the invention is not limited to modulating the phase. Preferably the modulation values are quantized and limited within intervals of adjacent paths of the optical structures. [0033] Features of the invention will become apparent from the drawings and following detailed discussion, which by way of example without limitation describe preferred embodiments of the invention. [0034] FIG. 1 is a perspective view of a backlight display device 10 . The backlight display device 10 comprises an optical source 12 for generating light 16 . A light guide 14 guides light 16 along its body from the optical source 12 . The light guide 14 contains disruptive features that permit the light 16 to escape the light guide 14 . Such disruptive features may include a surface manufactured from a master having a machined cutting gradient. A reflective substrate 18 positioned along the lower surface of the light guide 24 reflects light 16 escaping from a lower surface of the light guide 14 back through the light guide 16 and toward an optical substrate 24 . The optical substrate 24 may be fabricated from a positive or negative master having a nonrandomized, randomized or pseudo randomized surface 22 prepared according to the invention. [0035] At least one optical substrate 24 is receptive of the light 16 from the light guide 14 . The optical substrate 24 comprises a planar surface 20 on one side and the randomized three dimensional surface 22 on the second opposing side. Optical substrate 24 receives light 16 and turns and diffuses the light 16 in a direction that is substantially normal to the optical substrate 24 as shown. A diffuser 28 is located above the optical substrate 24 to provide diffusion of the light 16 . For example, the diffuser 28 can be a retarder film that rotates the plane of polarization of light exiting the optical substrate 24 to match the light to the input polarization axis of the LCD. The retarder film may be formed by stretching a textured or untextured polymer substrate along an axis in the plane of the substrate 24 . [0036] FIG. 1 shows a single substrate 24 . However, a backlight display device may comprise a plurality of substrates 24 positioned, one above the other, in a crossed configuration with respective prismatic structures 26 positioned at angles to one another. Yet further, one or both sides of the substrates 24 may comprise prismatic structures 26 . The optical substrate 24 may be formed by a process of electroforming from a work piece master that is fabricated as herein described below. The optical substrate 24 , however, is not limited to any particular fabrication process. [0037] FIG. 2 illustrates a method of machining a surface of a work piece such as a master shown generally at 100 . The work piece can be a master to model an optical substrate 24 having a nonrandomized, randomized or pseudo randomized surface 22 according to the invention. In FIG. 2 , a noise signal 102 is band pass filtered 104 and provided as input to a function generator 106 . A modulating mathematical function, such as a sinusoidal wave form is provided by the function generator 106 as input to a servo mechanism 108 . The noise signal 102 , the bandpass filter 104 and the function generator 106 can be replaced by a computer system equipped with the appropriate signal processing software and digital-to-analog conversion board so as to generate the input signal to the servo mechanism 108 . [0038] The servo mechanism 108 directs relative movement between the cutting tool 110 and the surface of a drum 112 rotating at an angular velocity of ω in a cylindrical coordinate system (r,θ,z). As the drum 112 rotates at angular velocity ω, the cutting tool 110 moves relative to the drum 112 along the drum axis, z, and may be driven back and forth with a frequency of up to about 10,000 Hz parallel to the z-axis of drum 112 (along the y-axis of the tool). The tool 110 may be driven back and forth parallel to the axis of the drum in a random or pseudo random nature in an embodiment of the invention. Cutting tool 110 is in continuous contact with the surface of rotating drum 110 to cut or machine a randomized spiral-like or threaded pattern 116 ( FIG. 4 ) of nominal pitch, P. A two axis cutting tool 110 moves back and forth parallel to the drum axis 112 and also perpendicular to the drum surface. [0039] Alternatively, the cutting tool 110 may be in contact with the surface of a flat plate 114 as seen in FIG. 6 , moving at a velocity of v in a rectilinear coordinate system (x,y,z). As plate 114 moves at velocity v, the cutting tool 110 is driven back and forth across the plate in a random or pseudo random nature to cut or machine a randomized triangular pattern 122 ( FIG. 6 ), for example, into the surface of the plate 114 . [0040] In an alternative embodiment of the invention, as seen in FIG. 5 , the drum 112 need not move along the z axis as the drum 112 rotates. As such, the cutting tool machines a randomized or pseudo randomized pattern along a series of concentric rings 118 in the surface of the drum 112 whereby the cutting tool returns to a starting point 122 for each cutting pass. To achieve good cutting quality, a control system can allow the cutting tool 110 to repeat the pattern of any i th cutting pass for the number of revolutions depending upon the desired final cut depth and in-feed rate. When the cutting tool 110 finishes the number of revolutions and returns to the starting point 122 of the (i−1) th cutting pass, the cutting tool 110 is shifted or stepped a distance S i , to be positioned at position S i for the next, or i th , cutting pass. [0041] The cutting tool 110 may have more than one axis of travel. For example it can have three axes of travel r, θ, z in cylindrical coordinates and x, y, z in rectilinear coordinates. Such additional axes allow for the cutting of toroidal lens type structures when using a radiused cutting tool 110 or allow for a gradient in the cut along the cut length, for example. Translational axes r, θ, z and x, y, z will also allow for introducing a cutting gradient into the pattern machined into the surface of the workpiece 112 , 114 for subsequent cutting passes. Such a cutting gradient is best seen with reference to FIG. 16 . In FIG. 16 , the i th cutting pass has a thickness or width of w i and the (i+1) th cutting pass has a thickness of w i+1 where w i is greater or less than w i+1 . In general, the n th cutting pass has a width of w n where w n is greater or less than w i , where i≠n. It will be understood that the change in the thickness in the cutting pattern in subsequent cutting passes may be nonrandom, random or pseudo random. Additional rotational degrees of freedom (e.g., pitch 152 , yaw 150 and roll 154 , FIGS. 2-7 ) may be used to change the angular orientation of the cutting tool 110 with respect to the surface of the workpiece 112 , 114 , thus changing the geometry of the facets machined into the master surface. [0042] The randomized or pseudo randomized pattern machined into the surface of the work piece 112 , 114 is in the nature of a number of paths of idealized structure, the idealized structure, hourly paths defined by mathematical function defined over a segment, C, of a coordinate system and characterized by a set of random or pseudorandom phase or other parameters. For a rotating drum 112 , the segment, C, over which the mathematical function is defined is the circumference of the drum 112 . For a moving plate 114 , the segment, C, over which the mathematical function is defined is a width or length of the plate 114 . An exemplary mathematical function is a function that is periodic over the segment C, such as that of the sine wave of Equation 1: y i =A i sin {φλ−Φ i }+S i   (1) defined relative to the segment C, i is an integer indicative of the i th surface path, y i is an instantaneous displacement of the path relative to C on the i th path, A i is an amplitude scaling factor of the i th path relative to C, and S i is a shift in a starting position of y i . φ is a number between zero and 2 π inclusive, and λ is a wavelength which is a real number. Φ i is a phase component for the i th path, wherein Φ i =Φ i−1 +Q i Δ+R i δ  (2) where Q i is randomly or pseudo randomly chosen number having a value of 1 or −1 and R i is a continuous random variable between −1 and 1, each defined for the i th path. Δ and δ are real numbers that define a magnitude of a phase stepping component and a magnitude of a phase dither component, respectively. The nominal y position S i is the y position without any modulation of the path. [0043] By limiting the absolute value of Q i Δ+R i δ to less than π radians the depth of the patterned surface is reduced since adjacent tool paths are not permitted to be π radians out of phase. [0044] In the more general case where multiple wavelengths are used simultaneously at each path, the idealized prismatic structure following a surface path is modulated by a mathematical function (3a) y i = ∑ k = 1 n ⁢ A i , k ⁢ sin ⁢ { ϕλ k - Φ i , k } + S i ( 3 ⁢ a ) defined relative to the segment C, wherein i is an integer indicative of the i th surface path, y i is an instantaneous displacement of the path relative to C on the i th path. A i,k is the k th amplitude scaling factor of the i th path relative to C, and S i is a shift in a starting position of y i , φ is a number between zero and 2 π inclusive, n is an integer greater than 1, and wavelength λ k is a real number. Φ i,k is the k th phase component of the i th path, wherein Φ i,k =Φ i−1,k +Q i,k Δ+R i,k δ  (3b) Q i,k is the k th randomly or pseudo randomly chosen number having a value of 1 or −1 for the i th path, R i,k is the k th continuous random variable having a value between −1 and 1 for the i th path, and Δ and δ are real numbers that define a magnitude of a phase stepping component and a magnitude of a phase dither component, respectively. The nominal y position S i is the y position without any modulation of the path. [0045] An even more general case for the function y i is provided by: y i = ∑ k = 1 n ⁢ A i , k ⁢ f ⁢ { ϕλ k - Φ i , k } + S i ( 4 ⁢ a ) Φ i , k = Φ i - 1 , k + Q i , k ⁢ Δ + R i , k ⁢ δ ( 4 ⁢ b ) where periodic function ƒ has been substituted for the sine function of equation (3a) in equation (4a). Such periodic functions include for example the well known triangular function, sawtooth function and square wave function. [0046] It will be understood that the mathematical function ƒ referred to above may be any mathematical function ƒ that can be programmed into a computer numerically controlled (CNC) machine. Such functions include for example the well known triangular function, sawtooth function and square wave function ( FIG. 14 ) each of which may be randomly modulated in phase. [0047] In another embodiment the paths of the idealized structure can be limited by allowing mixing of the amplitude adjacent tool paths. Suppose that y i is given by y i =A r i (φ)+ S i   (5) where r i (φ) is a band limited random or pseudo random function of φ for each i th path with a continuously varying value between −1 and 1, Ai is an amplitude constant, Si is the shift in starting position and the nominal y position for the i th path, and φ is in the range of 0 to 2π. The mixing may be introduced by use of a mixing parameter, m, such that part of the random vector for the (i−1)th random function is added to yi for the i th path as given in equation 6. y i =A [(1 −m ) r i (φ)+ m r i−1 (φ)]+ S i   (6) where m is a scalar mixing parameter with a value between 0 and 1. [0048] Referring to FIGS. 8 and 9 , the cutting tool 110 may comprise a prismatic structure having a cross section which may include straight facets 130 , 132 intersecting at a tip 134 at a peak angle of 2θ. The prismatic shaped cutting tool 110 may also comprise linear segments 130 , 132 of the facets 132 , 134 resulting in a compound angled prism. The compound angle prism has a first facet 138 at an angle of α and a second facet 140 at an angle of β with respect to a base 142 of the prism 110 . As best understood from FIGS. 8 and 9 , the cutting tool 110 may have a cross section with a rounded peak 134 or radius “r.” In general the cutting tool can have a cross section of any manufacturable shape. [0049] An example of the equipment used to machine the surface of the workpiece 112 , 114 in the invention is shown in FIG. 13 . Machining the surface of the workpiece 112 , 114 can be accomplished by computer numerically controlled (CNC) milling or cutting machine 202 . The machine 202 includes cutting tool 110 , which is controlled by a software program 208 installed in a computer 204 . The software program 208 controls the movement of the cutting tool 110 . The computer 204 is interconnected to the CNC milling machine 202 by an appropriate cabling system 206 . The computer 204 includes storage medium 212 for storing software program 208 , a processor for executing the program 208 , keyboard 210 for providing manual input to the processor, a display 218 and a modem or network card for communicating with a remote computer 216 via the Internet 214 or a local network. [0050] FIG. 15 illustrates a master machining system 400 with a fast tool servo for cutting workpiece grooves with lateral variations. An input/output data processor 402 provides cutting commands to a digital signal processing (DSP) unit 404 that supplies a signal to a digital-to-analog (DA) conversion device 406 . Voltage amplifier 408 receives a signal from the DA converter 406 and drives fast tool servo mechanism 410 to direct the motion of cutting tool 110 . Cutting tool position probe 412 senses a position of the cutting tool 110 and provides a signal indicative of the position to a sensor amplifier 418 . Amplifier 418 amplifies the signal. The amplified signal is directed to analog-to-digital (A/D) converter 420 . Lathe encoder 414 determines the position of the workpiece (e.g., drum 112 ) and provides a feedback signal to the A/D converter 420 . The A/D converter thus provides a feedback signal indicative of the position of the cutting tool 110 and the position of the workpiece 112 , 114 as output to the digital signal processing unit 404 . The DSP unit 404 provides a processed signal to the input/output processor 402 . [0051] The system 400 can provide a randomly or pseudo randomly machined workpiece surface. In operation, computer 204 with installed software program 208 is in communication with the CNC milling machine 202 . An operator may provide input value A i to personal computer 204 . The operator input can be provided manually by typing the A i value using keyboard 210 . Controlling mathematical function or functions may be stored within the computer's memory or may be stored on a remote computer 216 and accessed via the Internet 214 or via a local network. [0052] In operation, the A i value is provided to the CNC machine 202 . Then cutting element 110 of the CNC machine 202 begins to mill the workpiece 112 , 114 according to commands provided by the software program 208 that provides coordinates to direct movement of the cutting tool 110 . Additionally, the program 208 controls depth of the milling process. The process provides a nonrandomized, randomized or pseudo randomized workpiece that can be used as a “positive” or a “negative” master to produce an optical substrate. For example, the optical substrate 24 of FIG. 1 can be generated by forming a negative or positive electroform over the surface of the workpiece 112 , 114 . Alternatively, a molding material can be used to form a replica of an original positive or negative master—for example, an ultraviolet (UV) or thermal curing epoxy material or silicon material. Any of these replicas may be used as a mold for a plastic part. Embossing, injection molding, or other methods may be used to form the parts. [0053] Autocorrelation function, R(x,y), is a measure of the randomness of a surface in electro metrology. Over a certain correlation length, l c , however, the value of an autocorrelation function, R(x,y), drops to a fraction of its initial value. An autocorrelation value of 1.0, for instance, would be considered a highly or perfectly correlated surface. The correlation length, l c , is the length at which the value of the autocorrelation function is a certain fraction of its initial value. Typically, the correlation length is based upon a value of 1/e, or about 37 percent of the initial value of the autocorrelation function. A larger correlation length means that the surface is less random than a surface with a smaller correlation length. [0054] In some embodiments of the invention, the autocorrelation function value for the three-dimensional surface of the optical substrate 24 drops to less than or equal to 1/e of its initial value in a correlation length of about 1 cm or less. In still other embodiments, the value of the autocorrelation function drops to 1/e of its initial value in about 0.5 cm or less. For other embodiments of the substrate the value of the autocorrelation function along length l drops to less than or equal to 1/e of its initial value in about 200 microns or less. For still other embodiments, the value of the autocorrelation function along width w drops to less than or equal to 1/e of its initial value in about 11 microns or less. [0055] According to an embodiment of this invention, randomization of structures is accomplished with phase modulation only. For example, using randomization of the phase of a sine wave, or other periodic function, a modulated path can be achieved by applying a randomization algorithm to succeeding adjacent paths of the structures. A random number, such as a binary random number having only two possible values, is computer generated between each path. The number is then compared to a threshold. If the number is greater that the threshold then the phase of the next path is advanced by a constant, if the number is less than or equal to the constant, then the phase of the next path is delayed by a constant. As an example, the threshold could be 0.5 and the random number could be a binary number with possible values +1 and −1. The number of times that phase is changed by the randomization algorithm is at least once, and may be more than once. The present invention is not limited to a particular selected constant for changing the phase. The selected constant may be 120° or 90°, for example. With each next pass, the next phase is advanced or delayed by 120° (or 90°) according to whether the random number exceeds or is less than the constant. Of course different constants may be used, or a range of values within certain intervals, either symmetrical or unsymmetrical, can be used as threshold values. As an example of asymmetrical constants, the constant may be +120° and −90°, for example. [0056] The phase only limited modulation approach creates a highly randomized surface that has less overhead in depth. [0057] FIG. 17 is an illustration of an embodiment according to equation 5. Here “slide feed distance” is S i −S i−1 and “Random signal interval” is the amplitude of A i r i (φ). In this embodiment, y i may be a digital signal that is sampled along the drum circumference. [0058] FIG. 18 is an illustration of the embodiment according to equations 1 to 3 but illustrated with a sawtooth wave for simplicity instead of a sine. [0059] FIG. 19 is a replicate surface height map of a two wavelength phase shifting design occurring according to equation 4a to 4c. The surface shown is a negative copy of the drum surface. Here S i −S i−1 =45 um, n=2, A 1 +A 2 =22.5 um, λ 1 =170 um, λ 2 =20 mm, δ 1 =0, Δ 1 =π/3 radians, δ 2 =0, Δ 2 =π/3 radians and the prism peak angle is 90 degrees. [0060] FIG. 20 is an autocorrelation of the surface in FIG. 19 for a profile of the surface in a direction perpendicular to the circumferential direction. Note the autocorrelation length is less than 200 um. [0061] FIG. 21 is the surface height (depth) histogram for the surface shown is FIG. 19 . Note that total depth of the surface is 33 um. Here, using previous randomization algorithms would result in a peak to valley height of 45 um. If for example the desired peak to valley modulation is 45 um (in plane) then the modulation approach can be decomposed to a first component that is phase limited and a second component that is not. The height to pitch advantage of the invention will be partially reduced depending on the ratio of the two components and the phase limiting parameter(s). [0062] The height to pitch ratio will depend on the range of the phase steps allowed. A small phase step (5 degrees) will provide less randomization and a large phase step (170 degrees) will provide a deeper structure. +/−50-140 degrees is the preferred range. [0063] While preferred embodiments of the invention have been described, the present invention is capable of variation and modification and therefore should not be limited to the precise details of the Examples. The invention includes changes and alterations that fall within the purview of the following claims.
There is provided an optical substrate. The optical substrate includes at least one surface. The at least one surface includes at least one optical structure having a shape and dimensions, wherein the shape and dimensions of each optical structure represents in part a modulation of a corresponding idealized structure. The shape and dimensions of each of the at least one optical structure are determined in part by at least one randomly generated component of modulation wherein the modulation of each of the at least one optical structure is limited by a neighboring optical structure comprised by the surface.
6
CROSS-REFERENCE APPLICATION This application claims priority to U.S. Provisional Application No. 60/683,756, entitled “Method and Apparatus for Wellbore Communication” filed on May 23, 2005, which is hereby incorporated in its entirety. BACKGROUND OF THE INVENTION The present invention relates to telemetry systems for use in wellbore operations. More particularly, the present invention relates to telemetry systems for providing power to downhole operations and/or for passing signals between a position in a wellbore penetrating a subterranean formation and a surface unit. Wells are generally drilled into the ground to recover natural deposits of hydrocarbons and other desirable materials trapped in geological formations in the Earth's crust. A well is typically drilled by advancing a drill bit into the earth. The drill bit is attached to the lower end of a “drill string” suspended from a drilling rig. The drill string is a long string of sections of drill pipe that are connected together end-to-end to form a long shaft for driving the drill bit further into the earth. A bottom hole assembly (BHA) containing various instrumentation and/or mechanisms is typically provided above the drill bit. Drilling fluid, or mud, is typically pumped down through the drill string to the drill bit. The drilling fluid lubricates and cools the drill bit, and it carries drill cuttings back to the surface in the annulus between the drill string and the borehole wall. During conventional measurement while drilling (MWD) or logging while drilling (LWD) operations, signals are passed between a surface unit and the BHA to transmit, for example commands and information. Typically, the surface unit receives information from the BHA and sends command signals in response thereto. Communication or telemetry systems have been developed to provide techniques for generating, passing and receiving such signals. An example of a typical telemetry system used involves mud-pulse telemetry that uses the drill pipe as an acoustic conduit for mud pulse telemetry. With mud pulse telemetry, mud is passed from a surface mud pit and through the pipes to the bit. The mud exits the bit and is used to contain formation pressure, cool the bit and lift drill cuttings from the borehole. This same mud flow is selectively altered to create pressure pulses at a frequency detectable at the surface and downhole. Typically, the operating frequency is in the order 1-3 bits/sec, but can fall within the range of 0.5 to 6 bits/sec. An example of mud pulse telemetry is described in U.S. Pat. No. 5,517,164, the entire contents of which are hereby incorporated. In conventional drilling, a well is drilled to a selected depth, and then the wellbore is typically lined with a larger-diameter pipe, usually called casing. Casing typically consists of casing sections connected end-to-end, similar to the way drill pipe is connected. To accomplish this, the drill string and the drill bit are removed from the borehole in a process called “tripping.” Once the drill string and bit are removed, the casing is lowered into the well and cemented in place. The casing protects the well from collapse and isolates the subterranean formations from each other. After the casing is in place, drilling may continue or the well may be completed depending on the situation. Conventional drilling typically includes a series of drilling, tripping, casing and cementing, and then drilling again to deepen the borehole. This process is very time consuming and costly. Additionally, other problems are often encountered when tripping the drill string. For example, the drill string may get caught up in the borehole while it is being removed. These problems require additional time and expense to correct. The term “casing drilling” refers to the use of a casing string in place of a drill string. Like the drill string, a chin of casing sections are connected end-to-end to form a casing string. The BHA and the drill bit are connected to the lower end of a casing string, and the well is drilled using the casing string to transmit drilling fluid, as well as axial and rotational forces, to the drill bit. Upon completion of drilling, the casing string may then be cemented in place to form the casing for the wellbore. Casing drilling enables the well to be simultaneously drilled and cased. Examples of such casing drilling are provide in U.S. Pat. No. 6,419,033, US Patent Application No. 20040104051 and PCT Patent Application No. WO00/50730, all of which are incorporated herein by reference. Despite the advances in casing drilling technology, current casing drilling systems are unable to provide high speed communication between the surface and the bottom hole assembly. Therefore, what is needed is a system and method to provide a casing drilling system with high speed, low attenuation rate and/or enhanced band width signal capabilities. SUMMARY OF INVENTION In at least one respect, the present invention includes a communication system and method for a casing while drilling system. The casing while drilling system is adapted to advance into a subsurface formation via a casing. The communication system includes a high frequency modulator and a transducer. The modulator is positioned in the bottom hole assembly and adapted to generate a mud pulse by selectively restricting the mud flow passing therethrough. The transducer is adapted to detect the mud pulse generated by the modulator. In another aspect, the invention relates to a method of communicating with a bottom hole assembly of a casing while drilling system. The casing while drilling system is adapted to advance the bottom hole assembly into a subsurface formation via a casing. The method includes generating mud pulses at predefined frequencies by selectively restricting a mud flow passing through a modulator of the bottom hole assembly and detecting the mud pulses at the surface. BRIEF DESCRIPTION OF DRAWINGS So that the above recited features and advantages of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof that are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. FIG. 1 is a schematic view, partially in cross-section, of a rig having a casing drilling system for drilling a wellbore, the casing drilling system provided with a casing drilling communication system. FIG. 2A is a detailed view of the casing drilling system of FIG. 1 , the casing drilling system can ential a drilling, measurement, and/or formation evaluation assembly such as a rotary steerable (RSS), a measurement while drilling (MWD) and/or logging while drilling (LWD) system and a modulator. FIG. 2B is a detailed view of the casing drilling system of FIG. 1 , wherein the casing drilling communication system is run with a mud motor or turbo drill and the communication system is located uphole relative to the mud rotor. FIG. 3 is a detailed, exploded view of the modulator of FIG. 2 having a stator and a rotor. FIG. 4A is a detailed view of the modulator of FIG. 2 with the rotor in the open position relative to the stator. FIG. 4B is a detailed view of the modulator of FIG. 2 with the rotor in the closed position relative to the stator. FIGS. 5A-D are schematic view of the rotor and stator of FIG. 3 depicting the movement of the rotor relative to the stator. FIGS. 6A-D are graphs depicting the relationship between pressure versus time for the rotors and stators depicted in FIGS. 5A-D , respectively. FIG. 7 is a graph depicting signal strength versus depth at a first frequency and bit rate. FIG. 8 is a graph depicting signal strength versus depth at a second frequency and bit rate. DETAILED DESCRIPTION Referring to FIG. 1 , a casing drilling system 100 includes a rig 102 with a bottom hole assembly (BHA) 104 deployed into a borehole 106 via a casing 108 . The rig 102 has a traveling hook/block 126 , top drive 128 , guide rail and top drive/block dolly 130 and draw works 131 . A casing drive head/assembly 132 operatively connects the casing to the top drive 128 . The casing 108 extends through a conductor pipe 134 . Casing slips 136 are used to suspend the casing 108 string when adding a new joint of casing as drilling depth increases. In one embodiment, the BHA 104 includes a drill bit 118 at a downhole end thereof, a rotary steerable (RSS), measurement while drilling (MWD) and/or logging while drilling (LWD) assembly 125 , and an under reamer 122 . A BHA latch & seal assembly 124 operatively connects the BHA 104 to the casing 108 . Preferably, the latch & seal assembly 124 and the BHA 104 are retrievable through the casing 108 . The MWD/LWD assembly 125 preferably includes or communicates with a telemetry system or modulator, which is described in detail below, for communication with an acquisition and demodulation unit 127 . The acquisition and demodulation unit 127 typically resides in a surface unit, cabin or enclosure (not shown). A surface mud pit 110 with a mud 112 therein is positioned near the rig 102 . Mud 112 is pumped through feed pipe 114 by pump 116 and through the casing 108 as indicated by the arrows. Mud 112 passes through the BHA 104 , out of the drill bit 118 and back up through the borehole 106 . Mud 112 is then driven out an outlet pipe 120 and back into mud pit 110 . The drill bit 118 advances into a subterranean formation F and creates a pilot hole 138 . The under reamer 122 advances through the borehole 106 , expands the pilot hole 138 and creates an under-reamed hole 140 . The BHA 104 is preferably retrievable through the casing 108 on completion of the drilling operation. The under reamer 122 is preferably collapsible to facilitate retrieval through the casing 108 . Referring now to FIG. 2A depicts a portion of the casing drilling system 100 of FIG. 1 in greater detail. As mud 112 is pumped from feed pipe 114 through pump 116 , it passes by a pressure transducer 142 and down through the casing 108 to an RSS, MWD, and/or LWD assembly 125 as indicated by arrows 148 , 150 , and 152 . The mud 112 passes through the BHA 104 , exits the drilling bit 118 and returns through borehole 106 as indicated by arrows 154 , 156 and 158 . The RSS, MWD, and/or LWD assembly 125 uses a mud pulse system, such as the one described in U.S. Pat. No. 5,517,464, which is incorporated herein by reference. The RSS, MWD, and/or LWD assembly 125 includes a modulator 162 adapted to communicate with a surface unit (not shown). As mud 112 passes through the modulator 162 , the modulator 162 restricts the flow of the mud 112 and hence the pressure to generate a signal that travels back through the casing 108 as indicated by arrows 160 and 163 . The pressure transducer 142 detects the changes in mud pressure caused by the modulator 162 . The acquisition and demodulation unit 127 processes the signal thereby allowing the 104 to communicate to the surface through the unit 127 for uphole data collection and use. Referring now to FIG. 2B , an alternative embodiment is shown wherein a BHA 204 includes a drilling, measurement, and/or formation evaluation assembly 225 , such as RSS, MWD, and/or LWD, a mud motor or turbo-drill 210 , a drill bit 218 , an under-reamer 222 , and a data transmission module 224 . The mud motor 210 is located downhole or below a casing drilling modulator 262 , which is similar to the modulator 162 of FIG. 2A . Using a mud or drilling motor, such as the mud rotor 210 , provides the advantage of reducing the amount of rotations on the casing 108 . In one embodiment, the modulator 262 communicates with the transmission module 224 , which is in communication with other components or elements of the BHA 204 . In an alternative embodiment, the modulator 262 communicates directly with the other elements in the BHA 204 including the RSS, MWD, and/or LWD assembly 225 through various means including wired or wireless such as electromagnetic or ultrasonic methods. The scope of the present invention is not limited by the mean used for communication, which includes but is not limited to transmission through wired methods or wireless methods, which could include electromagnetic, ultrasonic or other means, or a combination thereof, such a wired and wireless or ultrasonic and electromagnetic combined with wired communication. Positioning the mud motor 210 downhole relative to the modulator 262 is the present embodiment which limits signal attenuation and produces the higher data rate and depth capability. Referring now to FIG. 3 , the modulator 162 of FIG. 2A and modulator 262 of FIG. 2B are depicted in greater detail. In each of the embodiments set forth herein, the modulator are similar in operation. Accordingly, even though the operation of one of the modulators is discussed in detail, the operation and results are applicable to similar types of modulators shown in alternative embodiments. The modulator 162 includes a stator 164 , rotor 166 and turbine 167 . The modulator 162 may be, for example, of the type described in U.S. Pat. No. 5,517,464, already incorporated herein by reference. In one embodiment, the modulator 162 is preferably a rotary or siren type modulator. Such modulators are typically capable of high speed operation, which can generate high frequencies and data rates. Alternatively, in another embodiment conventional “poppet” type or reciprocating pulsers may be used, but they tend to be limited in speed of operation due to limits of acceleration/deceleration and motion reversal with associated problems of wear, flow-erosion, fatigue, power limitations, etc. As the mud flow passes through the turbine 167 , the mud flow turns the turbine 167 and the rotation of the turbine 167 caused by the flow of mud generates power that can be used to power any required part of portion the BHA 104 , including the rotor 166 of modulator 162 . FIGS. 4A and 4B show the position of the rotor 166 and stator 164 . In FIG. 4A , the rotor 166 is in the open position. In other words, the rotor 166 is aligned with the stator 164 to permit fluid to pass through apertures 168 therebetween. In FIG. 4B , the rotor 166 is in the closed position, such that the apertures 168 are blocked, at least partially. In other words, the rotor 166 is mis-aligned with respect to the stator 164 to block at least a portion of the fluid passing through apertures 168 therebetween. The movement between the open and closed position creates a ‘pressure pulse.’ This pressure pulse is a signal detectable at the surface, and is used for communication. Referring now to FIGS. 5A-D , the flow of fluid past the rotor 166 and stator 164 is shown in greater detail in FIGS. 5A-D . In the open position ( FIG. 5A ), fluid passes with the least amount of restriction past stator 164 and rotor 166 . As the rotor 166 rotates and blocks a portion of the aperture 168 ( FIG. 5B ), fluid is partially restricted, thereby causing a change in pressure over time. The rotor 166 then rotates to a more restricted or closed position ( FIG. 5C ) and restricts at least a portion of the fluid flow. The rotor 166 advances further until it returns to the unobstructed position ( FIG. 5D ). Referring now to FIGS. 6A-D , the change in pressure over time is displayed in graphs of pressure-versus-time plots of the fluid flow for each of the rotor positions of FIGS. 5A-D , respectively. The following equations show the general effect of various parameters of the mud pulse signal strength and the rate of attenuation: S=S o exp[−4 πF ( D/d ) 2 (μ/ K )] where S=signal strength at a surface transducer; S o =signal strength at the downhole modulator; F=carrier frequency of the MWD signal expressed in Hertz; D=measured depth between the surface transducer and the downhole modulator; d=inside diameter of the drill pipe (same units as measured depth); μ=plastic viscosity of the drilling fluid; and K=bulk modulus of the volume of mud above the modulator; and by the modulator signal pressure relationship S o =(ρ mud ×Q 2 )/ A 2 where S o =signal strength at the downhole modulator; ρ mud =density of the drilling fluid; Q=volume flow rate of the drilling fluid; and A=the flow area with the modulator in the “closed” position The foregoing relationships demonstrate that a larger diameter of pipe, such as the casing 108 , makes higher carrier frequencies and data rates possible since the attenuation rate is lower for larger pipe diameters. Thus, for the specific application of casing drilling, the effect of the inside diameter “d”, as shown in FIG. 2 , makes higher carrier frequencies (hence, data rates) possible since the rate of attenuation is much less compared to conventional drill pipe. Accordingly, the ability to transmit at high frequencies and, hence the scope of the present invention, is determined by the foregoing relationships. The specific data rates provided below are for illustration purposes and not intended as a limiting example. Referring now to FIGS. 7 and 8 , graphs comparing the signal strength (y-axis) at various depths (x-axis) for a drill pipe in comparison to a casing. FIG. 7 shows the signal strength for a 5″ drill pipe ( 170 ) and 7″ casing ( 172 ). A minimum level ( 174 ) for detecting signal strength is also depicted. The graph illustrates the effect diameter has on signal strength in a 24 hz-12 bit/second deep water application using synthetic oil based mud. This shows that with the larger internal diameter of casing, 12 bit/sec telemetry rate is possible to about 20000 feet as compared to the smaller drill pipe diameter where 12 bit/sec is limited to about 13000 feet. Thus, the communication system described herein in this example can operate in the range of 1 bit/sec up to 12 bits/sec depending on the casing diameter and depth. FIG. 8 shows the signal strength for a 5″ drill pipe ( 180 ) and a 7″ casing ( 182 ). A minimum level ( 184 ) for detecting signal strength is also depicted. The graph illustrates the effect diameter has on signal strength in a 1 hz-1 bit/second deep water application using synthetic oil based mud. Typically, telemetry with drill pipe will be limited to 1 bit/sec, hence there is one order of magnitude higher data rate possible in these conditions with casing as compared to drill pipe. There is also an approximately four-fold increase in signal amplitude with casing as compared to drill-pipe for 1 Hz telemetry. It should be noted that both of the examples illustrated in FIGS. 7 and 8 are for comparison purpose only and that by changing the relevant parameters in the previously stated relationships, an increase in depth and/or data rate capability is possible. It will be understood from the foregoing description that various modifications and changes may be made in the preferred and alternative embodiments of the present invention without departing from its true spirit. Furthermore, this description is intended for purposes of illustration only and should not be construed in a limiting sense. The scope of this invention should be determined only by the language of the claims that follow. The term “comprising” within the claims is intended to mean “including at least” such that the recited listing of elements in a claim are an open set or group. Similarly, the terms “containing,” having, and “including” are all intended to mean an open set or group of elements. “A” or “an” and other singular terms are intended to include the plural forms thereof unless specifically excluded.
A communication system for a casing while drilling system is provided. The casing while drilling system is adapted to advance a bottom hole assembly into a subsurface formation via a casing. The communication system comprises a high frequency modulator and a transducer. The modulator is positioned in the bottom hole assembly and adapted to generate a mud pulse by selectively restrict mud flow passing therethrough. The transducer is adapted to detect the mud pulse generated by the modulator.
4
BACKGROUND [0001] 1. Technical Field [0002] This invention relates to a wind farm for producing electrical energy from wind and for injecting the generated electrical energy into an electrical supply grid. This invention also relates to a method for injecting electrical energy generated on a wind farm by multiple wind turbines. [0003] 2. Description of the Related Art [0004] It is generally known that electrical energy is generated by wind turbines from wind, where the term “generate” is used to describe that energy from the wind is converted into electrical energy. Often, multiple wind turbines are grouped together in one wind farm. Such a wind farm then has a collective injection point for supplying electrical energy into an electrical supply grid attached to it. All wind turbines in the wind farm therefore supply electrical energy into the electrical supply grid via this collective injection point. [0005] For example, supplying takes place in such a way that every wind turbine provides its electrical power as an alternating electric current to the electrical supply grid at the appropriate frequency, voltage amplitude and phase. Currents provided in this way from multiple wind turbines are superimposed at, or shortly before, the collective injection point and can therefore be supplied into the electrical supply grid together. [0006] In this way, any of the wind turbines in a wind farm can be operated together, because every wind turbine conditions the electrical current it is providing according to the correct values. It may then be necessary for all of the power being provided to be coordinated. [0007] However, the disadvantage in this case is that losses can occur at every wind turbine and in an internal wind farm grid, which creates a coupling between the wind turbines and the collective grid injection point, which could impair the overall efficiency of the wind farm as a result. [0008] The German Patent and Trademark Office has researched the following prior art in the priority application for this application: DE 101 45 346 A1 and DE 196 20 906 A1. BRIEF SUMMARY [0009] One of more embodiments of the present invention is may reduce one or more of the above-mentioned disadvantages. In one embodiment, the loss of performance inside the wind farm shall be reduced and the wind farm's efficiency shall be increased. [0010] According to one embodiment of the invention, a wind farm is provided for generating electrical energy from wind, and includes at least two wind turbines for the generation of electrical energy and one common feed-in device for supplying the electrical energy generated into a connected electrical supply grid. It may also be necessary, particularly temporarily, that only a part of the electrical energy that has been or could be generated is supplied into the electrical supply grid, if for example, this is required in order to support the electrical supply grid and/or based on specifications from the electrical supply grid operator. Otherwise, any power loss is omitted from the fundamental explanation of the invention. For the purposes of basic understanding, it is assumed that the electrical power being generated in the middle can also be supplied to the supply grid. If and when there is a loss of performance, this will be mentioned specifically. [0011] In the proposed solution, the wind turbines are connected to the feed-in device via a DC voltage grid, which can also be referred to as a DC voltage wind farm grid. In this way, the wind turbines supply their electrical energy or their electrical power, if any instantaneous state is considered, as electrical DC current to the DC voltage grid and this DC voltage, or these combined DC voltages from all of the wind turbines involved, is/are supplied to the feed-in device. The feed-in device now receives the total electrical output from the wind farm and can supply this to the electrical supply grid. [0012] This could also refer to supplying electrical DC voltage into the electrical DC voltage farm grid, such that the feed-in device draws the electrical power from the electrical DC voltage wind farm grid. To avoid confusion with the electrical supply grid, the term feeding into the DC voltage grid will be used here. [0013] It is therefore proposed that a DC voltage wind farm grid should be provided, and that the wind turbines connected to it also only feed DC current and DC voltage into this DC voltage wind farm grid. Therefore, the feed-in for the wind farm and therefore for multiple wind turbines can be managed by one single feed-in device. This is the element utilized to generate alternating current, which is adapted to the electrical supply grid in its frequency, voltage amplitude and phase. Any requirements, including requirements which have suddenly changed in the electrical supply grid, need only be provided by this feed-in device. It is this single feed-in device that detects the grid status, i.e., this feed-in device spontaneously allows for the appropriate values. It should also be noted that it is possible to position the feed-in device immediately beside or in close proximity to the feeding point, i.e., in close proximity to the electrical supply grid. This allows a more direct application of any measured values because, e.g., no or only slight loss of voltage occurs between the feed-in device and the electrical supply grid. [0014] Therefore, any loss of voltage between the respective wind turbines and the feed-in point no longer needs to be considered when supplying. Rather the feed-in device may adjust the voltage of the current signal it is generating to the voltage of the electrical supply grid. Due to the shorter distances between this feed-in device and the electrical supply grid, compared to the distance between a wind turbine in the wind farm and the electrical supply grid, voltage amplitudes can also be better adapted to the requirements of the electrical supply grid. [0015] Finally, frequency inverters that were previously required in the wind turbines are no longer required. Now, only one feed-in device is required. This single feed-in device must in fact transform the entire output from the wind farm and must therefore be correspondingly larger in size. However, this means it may be more efficient and therefore be operated with lower relative power loss. [0016] According to an embodiment, it is proposed that the DC voltage in the DC voltage grid ranges from 1 to 50 kV, and specifically from 5 to 10 kV. This refers to the voltage between two cables in a single bipolar topology. [0017] The wind turbines therefore supply their power at a correspondingly high voltage, namely at a medium voltage into the DC voltage grid of the wind farm. Transmission losses may be reduced by such a correspondingly high voltage in the DC voltage grid of the wind farm. Moreover, the voltage is already available to the common feed-in device at a certain amplitude, and can therefore negate the use of a transformer to step up electrical voltage inside the wind farm power grid. It can therefore be operated in the injection device using a medium-voltage inverter, i.e., the collective injection device can be a medium-voltage inverter, which requires less materials and may also make the use of a medium-voltage transformer redundant. [0018] Preferably, at least one of the wind turbines, but particularly all of the wind turbines in the wind farm, will have a generator, a rectifier and a boost converter. The generator is coupled with an aerodynamic rotor on the wind turbine and can therefore generate electrical power from the wind, which it delivers as electrical alternating current. The electrical alternating current is rectified by the rectifier into an initial direct current with an initial DC voltage. The boost converter raises the initial direct current and the initial DC voltage to a second direct current and a second DC voltage, and the second DC voltage is therefore higher than the initial DC voltage. The second DC voltage is then preferably fed into the DC voltage grid of the wind farm. The boost converter is therefore used to step up the initial direct current, specifically to the voltage amplitude required in the DC voltage grid. At the same time, the boost converter can perform the function of delivering a second DC voltage which is as steady as possible. The initial DC voltage can of course vary depending on wind fluctuations, and at low wind speeds it may generate a lower value than at higher wind speeds, or more particularly at a nominal wind speed. [0019] The rectifier is preferably situated in close proximity to the generator, specifically inside the wind turbine nacelle, and the initial direct current generated will then be transferred downwards through a wind turbine tower, or similar, to a tower base, or similar, where the boost converter is located. This means that the electrical output from the nacelle to the tower base, or similar, can take place using DC voltage transmission. At the same time however, the high medium-voltages provided in any case at height can be avoided, where they are envisaged in the DC voltage grid of the wind farm. [0020] According to another design, it is proposed that at least one of the wind turbines, and preferably all of the wind turbines in the wind farm, have a synchronous generator to generate electrical alternating current. This type of synchronous generator is able to reliably generate an electrical alternating current and supply a rectifier. The synchronous generator will preferably be designed as a ring generator, and its electromagnetically active elements will therefore be situated only on the external third or even further out. Preferably, such a synchronous generator can be equipped with a high number of poles, such as 48, 72, 96 or 144 poles for example. This allows for a gearless design, in which a runner in the generator can be directly operated by an aerodynamic rotor, i.e., without interconnected gears, and alternating current, which is transmitted to the rectifier, can be generated directly. Preferably, it will also be a synchronous generator with six phases, i.e., with two lots of three phases. This type of six-phase alternating current can be rectified more easily with narrower harmonics, i.e., smaller filters may suffice. Preferably, the wind turbines will be variable speed turbines, so that the rotation speed of the aerodynamic rotors can be continually adapted to the prevailing wind speed. [0021] According to one design, the injection device has an inverter connected to the DC voltage grid, i.e., the injection device is an inverter. This inverter generates the electrical alternating current being supplied into the electrical supply grid. Preferably a medium-voltage inverter will be used here. [0022] It is advantageous to use a transformer between the injection device and the electrical supply grid to step up the AC voltage being generated by the injection device. If a medium-voltage inverter is used, a medium-voltage transformer is not required. Depending on the electrical supply grid connected and the topology in between, it may be useful to use a high-voltage transformer here. A high-voltage transformer is particularly useful when a medium-voltage inverter is already generating an alternating current with a medium voltage, specifically with a voltage from 5 to 10 kV, and/or if a medium-voltage transformer is being used, which is generating the highest possible medium voltage of up to 50 kV. [0023] According to one embodiment of the invention, a process for supplying electrical energy into an electrical supply grid is also proposed. According to that process, electrical alternating current is generated using a generator in a wind turbine, and rectified by a rectifier into an initial direct current and an initial DC voltage. This initial DC voltage may vary in amplitude. This initial direct current and the initial DC voltage is therefore stepped up to a second direct current with a second DC voltage by a boost converter. This second DC voltage specifically has a greater amplitude than the initial DC voltage and is adapted to the voltage in the DC voltage wind farm grid, i.e., the overall DC voltage grid in the wind farm. [0024] This second direct current and the second DC voltage are correspondingly fed into the DC voltage wind farm grid. This DC voltage wind farm grid supplies this fed-in energy to a collective inverter or a multi-input inverter, which can also be referred to as the wind farm inverter, which inverts this energy supplied as direct current and supplies it into the electrical supply grid as alternating current. [0025] Preferably, multiple wind turbines will generate electrical alternating current (i.e. AC electrical signal), invert this into the initial direct current (i.e. initial DC electrical signal), step up the initial direct current into a second direct current (i.e. DC electrical signal), and finally feed the second direct current into the DC voltage wind farm grid. The terms “initial direct current”, “initial DC voltage” and “second direct current” are to be understood as systematic terms in this context, and amplitudes of the initial direct current, the initial DC voltage and the second direct current may vary from one wind turbine to another. Even if identical wind turbines are used, values can vary, e.g., depending on the prevailing wind and/or the position of the wind turbine concerned inside the wind farm. However, the second DC voltage should in any case be the same for all wind turbines in the initial approximation and correspond to the DC voltage in the DC voltage wind farm grid. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0026] The invention will now be explained in more detail using embodiments and with reference to the accompanying figures as examples. [0027] FIG. 1 shows a wind turbine to be used in a wind farm in a perspective view. [0028] FIG. 2 shows a wind farm. DETAILED DESCRIPTION [0029] FIG. 1 shows a wind turbine 100 with a tower 102 and nacelle 104 . An aerodynamic rotor 106 with three rotor blades 108 and a spinner 110 is located on the nacelle 104 . The rotor 106 is set in operation by the wind in a rotating movement and thereby drives a generator in the nacelle 104 . [0030] FIG. 2 shows a wind farm 1 , which has two wind turbines 2 as an example, one of which is annotated in more detail. These details were not repeated for the other turbine for the sake of simplicity, but it is to be noted that some of its details of the other turbine may be different. Both wind turbines 2 are connected by a DC voltage line 4 and a DC voltage busbar 6 to a collective inverter 8 or multi-input inverter. The collective inverter 8 generates alternating current with an AC voltage from the DC voltage or the direct current from the busbar 6 at its output 10 and supplies this into an electrical supply grid 14 , via a transformer 12 , which here is designed to be a medium-voltage transformer. [0031] The basic functionality and necessary elements are in any case explained according to an embodiment based on the detailed wind turbine 2 shown. Wind turbine 2 has an aerodynamic rotor 16 , which is turned by the wind and therefore turns a runner in a synchronous generator 18 , so that the synchronous generator 18 generated alternating current and supplies this to the rectifier 20 . The rectifier 20 is located in the nacelle 22 of the wind turbine 2 and there it generates an initial direct current and an initial DC voltage. The initial direct current and the initial DC voltage are supplied via a direct current connection cable 24 from the nacelle 22 via the tower 26 to the tower base 28 . The direct current connection cable 24 can therefore also be called a direct current tower cable. [0032] In the tower base 28 , the direct current connection cable 24 is coupled to a boost converter 30 . The boost converter 30 transforms the initial direct current and the initial AC voltage into a second direct current and a second DC voltage. This second direct current and the second DC voltage is generated at the output 32 of the boost converter 30 and fed in via the single DC voltage cable 4 to the busbar 6 . [0033] The initial DC voltage of the initial direct current, which occurs on the direct current connection cable 24 , i.e., direct current tower cable 24 , and therefore at the output of the inverter 20 is approximately 5 kV. The DC voltage applied to the DC voltage cable 4 , i.e., the DC voltage connection 4 , at the busbar 6 will preferably be 5 to 10 kV. This value is accordingly also applied at the busbar 6 and therefore at the input to the collective inverter 8 . Accordingly, the example shows the collective inverter 8 for transforming a direct current from 5 to 10 kV. The collective inverter 8 , which is therefore essentially a feed-in device, is therefore shown as a medium-voltage inverter. [0034] By using the topology illustrated, one inverter in every wind turbine 2 can be omitted. The collective inverter 8 being used can be operated, particularly when a medium-voltage inverter is used, as is also proposed in Figure 2 , with greater efficiency than would be possible for this with many individual inverters with lower voltages. FIG. 2 shows two wind turbines 2 in total, which is only intended to illustrate that multiple wind turbines 2 are present in the wind farm 1 . However, such a wind farm will preferably have more than two wind turbines 2 , specifically 50 wind turbines or more, which are all connected via a DC voltage cable 4 to the busbar 6 . The whole of the DC voltage cable 4 can therefore be called the DC voltage wind farm grid 4 or simply the DC voltage grid 4 in the wind farm. The DC voltage wind farm grid 4 is therefore not required to make any direct connection between individual wind turbines, which means, however, that there can be an indirect connection, such as is shown via the busbar 6 in Figure 2 . [0035] Depending on the design of the wind farm 1 and/or the electrical supply grid 14 , the medium-voltage transformer 12 can be omitted. All of the electrical power generated by the wind turbines 2 is supplied to the DC voltage grid 4 at the highest possible voltage, and is therefore supplied into the electrical supply grid 14 in the most efficient way possible using the collective inverter 8 . [0036] This means overall increases in the efficiency of the wind farm 1 are possible, specifically by reducing losses. Furthermore, it is possible to address some of the future requirements of the grid. Such grid requirements may, for example, be that a wind farm has to react to specific conditions in the electrical supply grid in a very deterministic way, or that it must react to requirements from the operator of the electrical supply grid in a particularly deterministic and clear way. Such requirements may also be specified very suddenly through appropriate signals. By using this collective inverter 8 , the wind farm 1 can be described as a wind farm generating station, which is only perceived by the electrical supply grid as a major electricity generator. Any differences in the wind turbines 2 in the wind farm 1 have no impact on or are not essential to the electrical supply grid 14 , or may not be perceived by the electrical supply grid 14 . These particularly include different time behaviors when operating on different statuses in the electrical supply network and/or different requirements from the electrical supply network 14 . [0037] It is therefore specifically proposed that all wind farm cabling should use DC voltage technology and a voltage range in the medium voltage range, specifically from approximately 5 to 10 kV. The wind turbines will not be equipped with inverters. The transfer of energy to a grid transmission station, illustrated in FIG. 2 as inverter 8 and busbar 6 , will take place using DC voltage. A medium-voltage inverter for supplying into the AC voltage grid, namely the electrical supply grid 14 , will therefore be used at the grid transmission station. This medium-voltage inverter meets all of the grid requirements, i.e., the requirements of the electrical supply grid, and also any reactive power requirements, i.e., requirements based on a proportion of reactive power to be supplied. [0038] A solution is therefore proposed which also meets the aims of constructing wind power plants in the most cost-efficient manner and with the highest possible efficiency level. [0039] The various embodiments described above can be combined to provide further embodiments. All of the U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, applications and publications to provide yet further embodiments. [0040] These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.
The invention concerns a wind farm for generating electrical energy from wind, including at least 2 wind turbines for producing the electrical energy and a collective injection device for injecting the electrical energy generated, or part of it, into an electrical supply grid, whereby the wind turbines are connected to the injection device via an electrical DC voltage grid, in order to supply the electrical energy generated using the wind turbines as electrical direct current to the injection device.
5
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a Continuation of co-pending U.S. patent application Ser. No. 12/428,622 filed on Apr. 23, 2009, which claims priority to Korean Patent Application No. 10-2008-0038117(filed on Apr. 24, 2008), which is hereby incorporated by reference in its entirety. BACKGROUND OF THE INVENTION [0002] 1. Field of Invention [0003] The present disclosure relates to a semiconductor light emitting device. [0004] 2. Discussion of the Related Art [0005] Group III-V nitride semiconductors have been variously applied to an optical device such as blue and green Light Emitting Diodes (LED), a high speed switching device such as a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) and a High Electron Mobility Transistor (HEMT), and a light source of a lighting device or a display device. Particularly, light emitting device using a group III nitride semiconductor has a direct transition bandgap corresponding to a region from visible rays to ultraviolet and can realize high-efficiency light radiation. [0006] The nitride semiconductor is mainly used for an LED or a Laser Diode (LD), and studies have been continuously conducted to improve the manufacturing process or light efficiency of the nitride semiconductor. SUMMARY OF THE INVENTION [0007] Embodiments provide a semiconductor light emitting device which comprises a second electrode layer under a plurality of compound semiconductor layers and a first electrode in the outer side thereof. [0008] Embodiments provide a semiconductor light emitting device which comprises a second electrode layer disposed under a light emitting structure, an insulator disposed on the one side of the second electrode layer and a first electrode disposed on the insulator. [0009] An embodiment provides a semiconductor light emitting device comprising: a first conductive semiconductor layer; an active layer under the first conductive semiconductor layer; a second conductive semiconductor layer under the active layer; a second electrode layer under the second conductive semiconductor layer; an insulator on one side of the second electrode layer; and a first electrode electrically connected to a one end of the first conductive semiconductor layer, on the insulator. [0010] An embodiment provides a semiconductor light emitting device comprising: a light emitting structure comprising a first conductive semiconductor layer, an active layer under the first conductive semiconductor layer, and a second conductive semiconductor layer under the active layer; a second electrode layer under the light emitting structure; a first electrode electrically connected to the first conductive semiconductor layer, in an outer side of the light emitting structure; and an insulator between the first electrode and the second electrode layer. [0011] An embodiment provides a semiconductor light emitting device comprising: a light emitting structure comprising a first conductive semiconductor layer, an active layer under the first conductive semiconductor layer, and a second conductive semiconductor layer under the active layer; a second electrode layer under the second conductive semiconductor layer; an insulator on the second electrode layer and in a one side of the light emitting structure; and a first electrode between the insulator and a one end of the first conductive semiconductor layer. [0012] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS [0013] FIG. 1 is a side-sectional view of a semiconductor light emitting device according to one embodiment. [0014] FIG. 2 is a diagram illustrating an example where a wire is bonded with the first electrode of FIG. 1 . [0015] FIGS. 3 to 8 are diagrams illustrating a process of manufacturing the semiconductor light emitting device according to one embodiment. [0016] FIG. 9 is a side-sectional view of a semiconductor light emitting device according to another embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS [0017] Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. [0018] In the following description, it will be understood that when a layer (or film) is referred to as being ‘on’ another layer or substrate, it can be directly on the another layer or substrate, or intervening layers may also be present. Further, it will be understood that when a layer is referred to as being ‘under’ another layer, it can be directly under the another layer, and one or more intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being ‘between’ two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. [0019] FIG. 1 is a side-sectional view of a semiconductor light emitting device according to one embodiment. FIG. 2 is a diagram illustrating an example where a wire is bonded with the first electrode of FIG. 1 . [0020] Referring to FIG. 1 , a semiconductor light emitting device 100 comprises a first conductive semiconductor layer 110 , an active layer 120 , a second conductive semiconductor layer 130 , a second electrode layer 140 , a conductive support member 150 , an insulator 160 , and a first electrode 170 . [0021] The semiconductor light emitting device 100 comprises a Light Emitting Diodes (LED) using a group III-V compound semiconductor. The LED may be a chromatic LED emitting chromatic light such as blue light, red light or green light, or may be an ultraviolet (UV) LED. The emission light of the LED may be variously implemented in the spirit and scope of embodiments. [0022] The first conductive semiconductor layer 110 may be selected from the compound semiconductors of group III-V elements (on which a first conductive dopant is doped), for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs and GaAsP. [0023] When the first conductive semiconductor layer 110 is an N-type semiconductor layer, the first conductive dopant comprises an N-type dopant such as Si, Ge, Sn, Se and Te. The first conductive semiconductor layer 110 may serve as an electrode contact layer and may be formed in a single layer or multi layers, but is not limited thereto. [0024] The first electrode 170 is electrically connected to the one end 115 of the first conductive semiconductor layer 110 . The first electrode 170 may be disposed under the one end 115 of the first conductive semiconductor layer 110 , or may be disposed in a line at an outer side. A power supply source having a first polarity is applied to the first electrode 170 . Herein, a roughness (not shown) of a certain shape may be formed on the entire surface of the first conductive semiconductor layer 110 , and may be added or modified in the spirit and scope of embodiments. [0025] Moreover, a translucent electrode layer (not shown) may be formed on the first conductive semiconductor layer 110 , and diffuses the power supply source having the first polarity applied by the first electrode 170 to an entire region. The translucent electrode layer may comprise at least one of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrOx, RuOx, RuOx/ITO, Ni/IrOx/Au and Ni/IrOx/Au/ITO. [0026] The active layer 120 is formed under the first conductive semiconductor layer 110 , and the active layer 120 may be formed in a single quantum well structure or a multiple quantum well structure. The active layer 120 may form the period of a well layer and a barrier layer, for example, the period of an InGaN well layer/GaN barrier layer or the period of an AlGaN well layer/GaN barrier layer by using the compound semiconductor materials of group III-V elements. [0027] The active layer 120 may be formed of a material having a bandgap energy according to the wavelength of an emitting light. The active layer 120 may comprise a material that emits a chromatic light such as a light having a blue wavelength, a light having a red wavelength and a light having a green wavelength, but is not limited thereto. A conductive clad layer may be formed on and/or under the active layer 120 , and may be formed in an AlGaN layer. [0028] The second conductive semiconductor layer 130 is formed under the active layer 120 , and may be formed of at least one of the compound semiconductors of group III-V elements (on which a second conductive dopant is doped), for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs and GaAsP. When the second conductive semiconductor layer 130 is a P-type semiconductor layer, the second conductive dopant may comprise a P-type dopant such as Mg and Ze. The second conductive semiconductor layer 130 may serve as an electrode contact layer and may be formed in a single layer or multi layers, but is not limited thereto. [0029] Herein, the first conductive semiconductor layer 110 , the active layer 120 and the second conductive semiconductor layer 130 may be defined as a light emitting structure 135 . Moreover, the first conductive semiconductor layer 110 may be formed of a P-type semiconductor, and the second conductive semiconductor layer 130 may be formed of an N-type semiconductor. A third conductive semiconductor layer, for example, an N-type semiconductor layer or a P-type semiconductor layer, may be formed under the second conductive semiconductor layer 130 . Accordingly, the light emitting structure 135 may comprise at least one of an N-P junction structure, a P-N junction structure, an N-P-N junction structure and a P-N-P junction structure. [0030] The second electrode layer 140 is formed under the second conductive semiconductor layer 130 . The second electrode layer 140 may be formed of a reflection electrode material, or may be formed of at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf and a material consisting of their selective combination. Herein, the reflection electrode material may be composed of a material having characteristic where a reflection rate is equal to or higher than 50%. [0031] An ohmic contact layer (not shown), in which a plurality of patterns are formed in a matrix shape or/and a layer type, may be formed in the second electrode layer 140 . The ohmic contact layer comprises at least one of materials such as ITO, IZO, AZO, IZTO, IAZO, IGZO, IGTO and ATO. [0032] Herein, the second electrode layer 140 may be schottky/ohmic contacted to the second conductive semiconductor layer 130 . When the ohmic contact layer exists, the second electrode layer 140 is schottky contacted to the second conductive semiconductor layer 130 , and the ohmic contact layer is ohmic contacted to the second conductive semiconductor layer 130 . Accordingly, the second electrode layer 140 and the ohmic contact layer may divide a current applied to the second conductive semiconductor layer 130 because they have different electrical characteristics. [0033] The second electrode layer 140 serves as an electrode which stably provides a power supply source having a second polarity to the light emitting structure 135 , and reflects light incident though the second conductive semiconductor layer 130 . [0034] The conductive support member 150 is formed under the second electrode layer 140 . The conductive support member 150 may be formed of at least one of copper (Cu), gold (Au), nickel (Ni), molybdenum (Mo), copper-tungsten (Cu—W) and carrier wafer (for example, Si, Ge, GaAs, ZnO, SiC and the like). The conductive support member 150 may be formed in an electro plating process, but is not limited thereto. [0035] The second electrode layer 140 and the conductive support member 150 may be used as a second electrode member which provides the power supply source having the second polarity to the light emitting structure 135 , and the second electrode member may be formed in a single layer or multi layers. Herein, the second electrode member having the single layer may be attached under the second conductive semiconductor layer 130 with adhesives. [0036] An etched region A 1 exists in the outer side of the light emitting structure 135 , which may be disposed more inward than the edge of the second electrode layer 140 . [0037] The first electrode 170 is insulated from the layers 120 , 130 and 140 by the insulator 160 , and is electrically connected to the first conductive semiconductor layer 110 . The first electrode 170 may be formed of at least one of Ti, Al, In, Ta, Pd, Co, Ni, Si, Ge, Ag and Au, but is not limited thereto. [0038] The insulator 160 comprises side wall portions 161 and 162 , a base portion 163 , and a support portion 164 . The insulator 160 may be formed of at least one of SiO 2 , Si 3 N 4 , Al 2 O 3 and TiO 2 . The side wall portions 161 and 162 of the insulator 160 are formed in the outer surface of the first electrode 170 , and may be formed in a circle or polygon shape. In this case, the first electrode 170 may be formed in a circle or polygon shape. [0039] The inner side wall portion 161 of the side wall portions 161 and 162 is disposed between the first electrode 170 and the outer side of the second conductive semiconductor layer 130 and the active layer 120 , and insulates the inner side surface of the first electrode 170 from the layers 120 and 130 . Moreover, the inner side wall portion 161 is extended to the bottom of the one end 115 of the first conductive semiconductor layer 110 , and can electrically disconnect the first electrode 170 and the active layer 120 . The one end 115 of the first conductive semiconductor layer 110 is formed to partially overlap on the first electrode 170 . [0040] The outer side wall portion 162 of the side wall portions 161 and 162 insulates other side surface of the first electrode 170 in the channel region of a chip, and prevents the outer side of the first electrode 170 from being exposed. [0041] The base portion 163 is formed between the first electrode 170 and the second electrode layer 140 , and is disposed under the side wall portions 161 and 162 . The base portion 163 is formed on the one side of the second electrode layer 140 , and electrically insulates the first electrode 170 and the second electrode layer 140 . [0042] The support portion 164 extended to the inner side of the base portion 163 is disposed between the second conductive semiconductor layer 130 and the second electrode layer 140 , and prevents the insulator 160 from being separated from a chip. [0043] A passivation portion 165 may be formed around the top of the second electrode layer 140 . The passivation portion 165 has a ring shape or a belt shape, and may be connected to the base portion 163 of the insulator 160 . The material of the passivation portion 165 may be the same as that of the insulator 160 . That is, the insulator 160 may further comprise the passivation portion 165 . [0044] Moreover, the passivation portion 165 may be formed in a material different from the insulator 160 , for example, a conductive material. For example, the passivation portion 165 may comprise at least one of ITO, IZO, AZO, IZTO, IAZO, IGZO, IGTO and ATO. The passivation portion 165 may not be formed. [0045] The passivation portion 165 separates the light emitting structure 135 from the second electrode layer 140 , and thus, can prevent influences that are transferred from the second electrode layer 140 to the side wall of the light emitting structure 135 . [0046] The first electrode 170 is disposed on the outer side of the light emitting structure 135 and the one side of the second electrode layer 140 by the insulator 160 , is electrically connected to the first conductive semiconductor layer 110 , and is electrically opened from the layers 120 , 130 and 140 . [0047] Referring to FIG. 2 , a wire 180 is bonded on the first electrode 170 . In this case, the wire 180 is connected to the first electrode 170 which is disposed in the outer side of the semiconductor light emitting device 100 , and thus, may be disposed outward the semiconductor light emitting device 100 . [0048] The power supply source having the first polarity is provided to the first conductive semiconductor layer 110 through the first electrode 170 , and the power supply source having the second polarity is provided through the conductive support member 150 and the second electrode layer 140 . Light radiated from the active layer 120 of the semiconductor light emitting device 100 is irradiated in a forward direction. [0049] At this point, there is no obstacle in the top of the first conductive semiconductor layer 110 , thereby decreasing obstacles that obstructs the traveling of light L 1 . [0050] For example, if the first electrode is disposed in the top of the first conductive semiconductor layer and a wire is bonded, the following limitations may occur. The first electrode and the wire may serve as obstacles that obstruct a light path extracted to the top of the first conductive semiconductor layer. That is, there may occur limitations that the wire and the first electrode disposed in the upper side of the first conductive semiconductor layer absorb light. [0051] The first electrode 170 is disposed in the side of the semiconductor light emitting device 100 , and thus, the wire 180 does not pass though the upper portion of the semiconductor light emitting device 100 . Accordingly, light extraction efficiency can be improved. [0052] FIGS. 3 to 8 are diagrams illustrating a process of manufacturing the semiconductor light emitting device according to one embodiment. [0053] Referring to FIG. 3 , the light emitting structure 135 on which a plurality of compound semiconductor layers are stacked is formed on a substrate 101 . The light emitting structure 135 may comprise the first conductive semiconductor layer 110 , the active layer 120 and the second conductive semiconductor layer 130 which are sequentially stacked. [0054] The substrate 101 may be selected from the group consisting of sapphire substrate (Al 2 O 3 ), GaN, SiC, ZnO, Si, GaP, InP and GaAs. A concave-convex pattern may be formed on the substrate 101 , but is not limited thereto. [0055] A group III-V compound semiconductor may grow on the substrate 101 . Herein, the growth equipment of the compound semiconductor may be implemented with electron beam evaporator, Physical Vapor Deposition (PVD), Chemical Vapor Deposition (CVD), Plasma Laser Deposition (PLD), dual-type thermal evaporator, sputtering and Metal Organic Chemical Vapor Deposition (MOCVD), but is not limited thereto. [0056] A buffer layer (not shown) or/and an undoped semiconductor layer (not shown) may be formed on the substrate 101 . The buffer layer may be formed of a single crystal buffer layer or a group III-V compound semiconductor, and decreases a lattice constant difference with the substrate 110 . The undoped semiconductor layer may be formed of a GaN-based semiconductor. The substrate 101 , the buffer layer and the undoped semiconductor layer may be separated or removed after the growth of a thin film. Herein, a separate patterned metal material (not shown) may be formed between the substrate 101 and the first conductive semiconductor layer 110 for protecting the active layer 120 . [0057] The first conductive semiconductor layer 110 is formed on the substrate 101 . The first conductive semiconductor layer 110 may be selected from the compound semiconductors of group III-V elements (on which a first conductive dopant is doped), for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs and GaAsP. When the first conductive semiconductor layer 110 is an N-type dopant, the first conductive dopant comprises an N-type dopant such as Si, Ge, Sn, Se and Te. [0058] The active layer 120 is formed of a group III-V compound semiconductor on the first conductive semiconductor layer 110 , and has a single quantum well structure or a multiple quantum well structure. The active layer 120 may comprise a material that emits a chromatic light such as a light having a blue wavelength, a light having a red wavelength and a light having a green wavelength. A conductive clad layer may be formed on and/or under the active layer 120 and may be formed in an AlGaN layer, but is not limited thereto. [0059] The second conductive semiconductor layer 130 is formed on the active layer 120 , and may be formed of at least one of the compound semiconductors of group III-V elements (on which a second conductive dopant is doped), for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs and GaAsP. When the second conductive semiconductor layer 130 is a P-type semiconductor layer, the second conductive dopant may comprise a P-type dopant such as Mg and Ze. [0060] A third conductive semiconductor layer, for example, an N-type semiconductor layer or a P-type semiconductor layer, may be formed on the second conductive semiconductor layer 130 . Accordingly, the light emitting structure 135 may comprise at least one of an N-P junction structure, a P-N junction structure, an N-P-N junction structure and a P-N-P junction structure. [0061] Referring to FIG. 4 , the one-side region 167 of the second conductive semiconductor layer 110 is exposed in a first mesa etching process. Herein, the first mesa etching process is performed in a portion of the second conductive semiconductor layer 130 until the first conductive semiconductor layer 110 is exposed in a dry or/and wet etching process. The etching process may be changed in the spirit and scope of embodiments. [0062] The first electrode 170 is formed in the one-side region 167 of the first conductive semiconductor layer 110 . The first electrode 170 may be formed of at least one of Ti, Al, In, Ta, Pd, Co, Ni, Si, Ge, Ag and Au, but is not limited thereto. The one side of the first conductive semiconductor layer 110 contacts the bottom of the first electrode 170 , and the size of the contacted region may be changed according to an etching region by the first mesa etching process. [0063] Herein, the bottom of the first electrode 170 may be electrically connected to the first conductive semiconductor layer 110 . [0064] The thickness H 1 of the first electrode 170 heightens or lowers the top of the second conductive semiconductor layer 130 . [0065] The first electrode 170 is separated from the second conductive semiconductor layer 130 and the side surface of the active layer 120 at a certain interval, and may be formed in a circle shape, a polygon shape or a line shape. [0066] Referring to FIG. 5 , the insulator 160 is formed in the outer surface and top of the first electrode 170 . The insulator 160 comprises the side wall portions 161 and 162 , the base portion 163 and the support portion 164 , and covers the exposed region of the first electrode 170 . The insulator 160 may be formed of at least one of SiO 2 , Si 3 N 4 , Al 2 O 3 and TiO 2 . [0067] The side wall portions 161 and 162 are formed in the outer surface of the first electrode 170 . The inner side wall portion 161 insulates the inner side surface of the first electrode 170 and the first conductive semiconductor layer 110 , and insulates the active layer 120 and the one side of the second conductive semiconductor layer 130 . The outer side wall portion 162 insulates other side surface of the first electrode 170 in the channel region of the chip. Accordingly, the side wall portions 161 and 162 prevent the outer side of the first electrode 170 from being exposed. [0068] The base portion 163 is formed in the top of the first electrode 170 , and insulates the top of the first electrode 170 . The support portion 164 extended to the inner side of the base portion 163 supports the entirety of the insulator 160 . [0069] The passivation portion 165 may be formed along the outer side of the top of the second conductive semiconductor layer 130 . The passivation portion 165 has a ring shape or a belt shape, and may be connected to the base portion 163 of the insulator 160 . The material of the passivation portion 165 may be the same as that of the insulator 160 . That is, the insulator 160 may further comprise the passivation portion 165 . [0070] Moreover, the passivation portion 165 may be formed in a material different from the insulator 160 , for example, a conductive material. For example, the passivation portion 165 may comprise at least one of ITO, IZO, AZO, IZTO, IAZO, IGZO, IGTO and ATO. The passivation portion 165 may not be formed. [0071] Referring to FIG. 6 , the second electrode layer 140 is formed on the second conductive semiconductor layer 130 and the insulator 160 , the conductive support member 150 is formed on the second electrode layer 140 . [0072] The passivation portion 165 , which is disposed around the top of the second conductive semiconductor layer 130 , separates the light emitting structure 135 from the second electrode layer 140 , and thus, can prevent influences that are transferred from the second electrode layer 140 to the side wall of the light emitting structure 135 . [0073] The second electrode layer 140 may be formed of at least one of reflection electrode materials, for example, Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf and a material consisting of their selective combination. An ohmic contact layer (not shown), in which a plurality of patterns are formed in a matrix shape or/and a layer type, may be formed between the second electrode layer 140 and the second conductive semiconductor layer 130 . The ohmic contact layer comprises at least one of materials such as ITO, IZO, AZO, IZTO, IAZO, IGZO, IGTO and ATO. [0074] The second electrode layer 140 serves as an electrode which stably provides the power supply source having the second polarity to the light emitting structure 135 . Herein, the second electrode layer 140 may be schottky/ohmic contacted to the second conductive semiconductor layer 130 . When the ohmic contact layer exists, the ohmic contact layer and the second electrode layer 140 may divide a current applied to the second conductive semiconductor layer 130 because they have different electrical resistances. [0075] The conductive support member 150 may be formed of at least one of Cu, Au, Ni, Mo, Cu—W and carrier wafer (for example, Si, Ge, GaAs, ZnO, SiC and the like). Herein, the second electrode layer 140 , for example, may be formed in a sputtering process. The conductive support member 150 , for example, may be formed in a plating process. The formation processes may be changed in the spirit and scope of embodiments. [0076] Referring to FIGS. 6 and 7 , the substrate 101 is removed. In this case, the substrate 101 is disposed upward and is removed. [0077] The substrate 101 that is disposed under the first conductive semiconductor layer 110 is removed in a physical/chemical process. For example, when laser ray having a wavelength of a certain region is irradiated to the substrate 101 , a heating energy is concentrated on a boundary surface between the substrate 101 and the first conductive semiconductor layer 110 , and thus the substrate 101 is separated. Furthermore, a polishing process using an Inductively coupled Plasma/Reactive Ion Etching (ICP/RCE) process may be performed on the surface of the first conductive semiconductor layer 110 from which the substrate 101 has been removed. [0078] When a non-conductive semiconductor layer, for example, a buffer layer or/and an undoped semiconductor layer exists between the substrate 101 and the first conductive semiconductor layer 110 , it may be removed in an etching process or a polishing process, but is not limited thereto. [0079] Referring to FIGS. 7 and 8 , the one side of the first conductive semiconductor layer 110 is disposed on the first electrode 170 and the insulator 160 . [0080] A roughness (not shown) of a certain shape may be formed on the top of the first conductive semiconductor layer 110 . Moreover, a translucent electrode layer (not shown) may be formed on the first conductive semiconductor layer 110 , and may diffuse a current. The translucent electrode layer may comprise at least one of ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, gallium zinc oxide (GZO), IrOx, RuOx, RuOx/ITO, Ni/IrOx/Au and Ni/IrOx/Au/ITO. [0081] A second mesa etching process is performed on the light emitting structure 135 . In this case, an etched region A 1 exists in the outer perimeter of the light emitting structure 135 , which is disposed more inward than the edge of the second electrode layer 140 . Herein, the region A 1 may not exist. [0082] The second mesa etching process may use a wet or/and dry etching process, and may be changed in the spirit and scope of embodiments. [0083] When the second mesa etching process is performed in a portion of the one-side region D 1 of the first conductive semiconductor layer 110 , the top of the first electrode 170 is exposed in the one side of the first conductive semiconductor layer 110 . [0084] Since the certain region D 2 of the first conductive semiconductor layer 110 is disposed to overlap on the first electrode 170 , the first electrode 170 is electrically connected to the one end 115 of the first conductive semiconductor layer 110 . [0085] In the semiconductor light emitting device 100 , the first electrode 170 is disposed in the side direction of the first conductive semiconductor layer 110 , and a wire bonded to the first electrode 170 may be disposed in the outer side of the semiconductor light emitting device 100 . Accordingly, the light extraction efficiency of the semiconductor light emitting device 100 can be improved. [0086] FIG. 9 is a side-sectional view of a semiconductor light emitting device according to another embodiment. In description of another embodiment, repetitive description on the same elements as those of one embodiment will be omitted and refers to that of one embodiment. [0087] Referring to FIG. 9 , a semiconductor light emitting device 100 A according to another embodiment comprises the first conductive semiconductor layer 110 , the active layer 120 , the second conductive semiconductor layer 130 , the second electrode layer 140 , the conductive support member 150 , a plurality of insulators 160 and 160 A, and a plurality of first electrodes 170 and 170 A. [0088] The plurality of insulators 160 and 160 A are disposed in the both sides of the light emitting structure 135 respectively, and electrically insulate the first electrodes 170 and 170 A and the layers 120 , 130 and 140 . A detailed description on the insulators 160 and 160 A refers to one embodiment. [0089] In the plurality of first electrodes 170 and 170 A, regions D 2 and D 3 where the one side 115 and other side 117 of the first conductive semiconductor layer 110 overlap may be identical to or different from each other. [0090] The plurality of first electrodes 170 and 170 A may be electrically connected by an electrode pattern formed on the first conductive semiconductor each other. [0091] In the semiconductor light emitting device 100 A, the first electrodes 170 and 170 A are disposed in the both-side directions of the first conductive semiconductor layer 110 respectively, and a plurality of wires bonded to the first electrodes 170 and 170 A may be disposed in the outer side of the semiconductor light emitting device 100 A. Accordingly, the light extraction efficiency of the semiconductor light emitting device 100 A can be improved. [0092] Embodiments dispose the first electrode in the outer side of the plurality of compound semiconductor layers, thereby solving light absorption limitations due to the first electrode and the wire. [0093] Embodiments can improve light efficiency. [0094] Embodiments can improve the reliability of the semiconductor light emitting device. [0095] Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.
A semiconductor light emitting device, including a reflective electrode layer; a second conductive semiconductor layer formed on a portion of a top surface of the reflective electrode layer; an active layer formed on the second conductive semiconductor layer; a first conductive semiconductor layer formed on the active layer; a first electrode formed under one portion of the first conductive semiconductor layer; and an insulating layer having a lower portion, a first upwardly directed side wall portion at a first side of the first electrode and a second upwardly directed side wall portion at a second side of the first electrode that is opposite to the first side. At least one portion of the lower portion is between the second conductive semiconductor layer and the reflective electrode layer.
7
The subject of this patent relates to optimization of systems including industrial processes, equipment, facilities, buildings, homes, devices, engines, robots, vehicles, aircraft, space-vehicles, appliances and other systems, and more particularly to a method and apparatus for automatically optimizing a process or system based on the optimal objectives without using mathematical models of the process or system. In the U.S. Pat. Nos. 6,055,524, 6,556,980 B1, and 6,360,131 B1, Model-Free Adaptive (MFA) control technology was introduced. In this patent, we expand the Model-Free Adaptive method from automatic control to automatic optimization. Optimization has four key elements: (1) Objectives—the objectives that define what to achieve; (2) Conditions and Constraints—the conditions and constraints that may not allow the achievement of some of the objectives; (3) Acceptable Solutions—all possible solutions that allow the achievement of some or all of the objectives; and (4) Optimal Solution—the solution that makes the most sense after the tradeoff between the conflicts in objectives and constraints. Optimization problems can be difficult to solve due to the following reasons: (1) the process input-output relationship is typically dynamic, multivariable, nonlinear, and time-varying; (2) there are multiple operating conditions and constraints; (3) the process signals are frequently contaminated by noises and disturbances; (4) online optimization is required; and most importantly, (5) it is difficult to develop and maintain a process model or a set of rules. Traditional optimization is dependent on the first-principle or identification based mathematical models or rules. The Model-Free Adaptive Optimization technology can solve many optimization problems without the need to build such models or rules. Running in real-time, the MFA optimizer can automatically search for the optimal operating point for a dynamic system when a parabolic relationship exists between the input and output. The MFA optimization technology is useful in fuel-and-air ratio optimization for combustion processes, yield optimization for chemical or biological reactors, and operating efficiency optimization for coal or ore ball mills. In the accompanying drawing: FIG. 1 is a block diagram illustrating a single-input-single-output (SISO) Model-Free Adaptive (MFA) optimization system where an MFA optimizer optimizes a single-input-single-output (SISO) process. FIG. 2 is a drawing illustrating the process input-output relationship, where there is either a maximum or minimum as an optimal point. FIG. 3 is a flow chart describing the steps in a process acting mode search engine mechanism in an MFA optimizer. FIG. 4 is a flow chart describing the steps in a maximum search engine mechanism in an MFA optimizer. FIG. 5 is a flow chart describing the steps in a minimum search engine mechanism in an MFA optimizer. FIG. 6 is a flow chart describing the main search engine of an MFA optimizer. The term “mechanism” is used herein to represent hardware, software, or any combination thereof. The term “process” is used herein to represent a physical system or process with inputs and outputs that have dynamic relationships. DESCRIPTION A. SISO Model-Free Adaptive (MFA) Optimizer FIG. 1 illustrates a single-input-single-output (SISO) Model-Free Adaptive (MFA) optimization system. It comprises a SISO MFA optimizer 10 , a SISO process 12 , signal adders 14 , 16 , and a Min/Max Setter 18 . The signals shown in FIG. 1 are as follows: r(t)—Setpoint. y(t)—Measured Process Variable, y(t)=x(t)+d(t). x(t)—Process Output. u(t)—Optimizer Output that is applied to the Process Input. d(t)—Disturbance, the disturbance caused by noise or load changes. e(t)—Error between the Setpoint and Measured Variable, e(t)=r(t)−y(t). Assume that there is an optimal point in the process input-output relationship, and assume that we can manipulate the process input within its range to allow the process output to reach the optimal point, where the process input range may be bounded by limits or constraints. The optimization objective is for the SISO MFA optimizer to produce an output u(t) to force the measured process variable y(t) to reach the optimal point and stay near there under variations in process dynamics, disturbances, noises, and other uncertainties. Unlike any other traditional optimization system, the SISO MFA optimization system uses the same structure as a SISO feedback control system. It makes the implementation and use of such a system easy and user-friendly. The SISO MFA optimizer can be implemented in the same environment as SISO feedback controllers including but not limited to PID (proportional-integral-derivative) controllers and SISO MFA controllers. On the other hand, since the SISO feedback control systems are the most popular control systems and most control engineers and process operators are familiar with the structure and variables, the SISO MFA optimizers are easy to learn, use, and maintain. The Min/Max Selector 18 allows the user to choose when to use the optimizer to find a minimum or a maximum. Depending on the information, the MFA Optimizer can move the setpoint to its low limit or high limit accordingly. As an example, consider a system where the setpoint and the process variable have a range of 0% to 100%. The low setpoint limit is 5% and the high setpoint limit is 95%. If the Min/Max Selector is set to search for a minimum, setpoint r(t) can be set to 5%. Similarly, if the Min/Max Selector is set to search for a maximum, setpoint r(t) can be set to 95%. As another example, consider a system where the setpoint and process variable have a range of 150 degrees Fahrenheit to 650 degrees Fahrenheit. The low setpoint limit is at 200 degrees Fahrenheit and the high setpoint limit is at 600 degrees Fahrenheit. If the Min/Max Selector is set to search for a minimum, setpoint r(t) can be set to 200 degree F.; and if the Min/Max Selector is set to search for a maximum, setpoint r(t) can be set to 600 degree F. This setpoint setting arrangement allows the MFA optimizer to produce an error e(t) so that it will continuously search for the optimal point towards the right direction. This is because the search will not stop unless the process variable y(t) reaches the setpoint r(t) or an optimal point. The algorithm for producing the output u(t) for the MFA optimizer will be discussed in the final portion of the description. FIG. 2 is a drawing illustrating the process input-output relationship, where there is a maximum or minimum as an optimal point. Curve 20 of the top chart shows that when u(t) starts to increase from 0, y(t) increases. This relationship continues until y(t) reaches a maximum and then it starts to decrease. This type of process can be either direct-acting or reverse-acting depending on the operating point. From a control point of view, the process is not controllable when using regular feedback controllers. Since the process changes its sign, it will cause a negative feedback loop to become a positive feedback loop. An automatic control system is based on negative feedback in order to be closed-loop stable. In contrast, from an optimization point of view, this process can be optimized since there exists an optimal point that can be reached. If a process is only direct-acting or reverse-acting, there will be no optimal point to reach. Then, the process may be controllable but cannot be optimized since no maximum or minimum exists. Curve 22 of the bottom chart shows that when u(t) starts to increase from 0, y(t) decreases and the relationship continues until y(t) reaches a minimum and then it starts to increase. Similarly, this process changes its sign and cannot be controlled by conventional feedback controllers but can be optimized since there exists a minimum as an optimal point. FIG. 3 is a flow chart describing the steps in a process acting mode search engine mechanism in an MFA optimizer. It describes the method for detecting whether the process is in a direct-acting mode or reverse-acting mode. At Block 26 , initialization is taking place including the tasks to clear the direct-acting counter (Let DA_Count=0), clear the reverse-acting counter (Let RA_Count=0), and set the direct-acting flag to its default value (Let DA_Flag=ON). These counters and the flag are variables in the acting mode search engine mechanism. At Block 28 , the optimizer output is increased by Δu(t), and at Block 30 , it waits for a period of time, Tx. This is the estimated delay time between the process input and output, which is user-configurable. At Block 32 , the routine checks the measured process variable y(t) to see if its value has increased in comparison to its previous values. If the answer is Yes, the routine goes to Block 34 to increase the direct-acting counter by 1 and clear the reverse-acting counter. If the answer is No, the routine goes to Block 36 to increase the reverse-acting counter by 1 and clear the direct-acting counter. These counters are used to record the number of times the acting type has been detected. At Block 38 , DA_Count value is checked. If it is larger than 2, it means that the process has been detected in the direct-acting mode in the past 3 consecutive tries. The routine will move to Block 42 to set the DA_Flag to ON and exit. Notice that the number of tries required to guarantee the detection of the acting mode may depend on the process and is user configurable. Here, we use 3 tries as an example. This applies to all the counters used in the search engines in this patent. If the DA_Count value is not larger than 2, the routine goes back to Block 28 to perform one more round of detection. If the routine is branched to Block 36 , it will continue to Block 40 to check the RA_Count. Similarly, if its value is larger than 2, it means that the process has been detected in the reverse-acting mode in the past 3 consecutive tries. The routine will move to Block 44 to set the DA_Flag to OFF to indicate that the process is in the reverse-acting mode and then exit. If the RA_Count value is not larger than 2, the routine goes back to Block 28 to perform one more round of detection. Notice that the y(t) signal might be contaminated with noise. It is necessary to use filters such as low pass filters to remove high frequency noises before applying this routine and other search engine routines in this patent. FIG. 4 is a flow chart describing the steps in a maximum search engine mechanism in an MFA optimizer. At Block 50 , initialization is taking place including the tasks to clear the maximum counter (Max_Count) and maximum flag (Max_Flag). The counter and flag are variables in the maximum search engine mechanism. At Block 52 , the routine checks the process acting mode. If it is in the direct-acting mode, optimizer output u(t) is increased by Δu(t) at Block 54 . If it is in the reverse-acting mode, optimizer output u(t) is decreased by Δu(t) at Block 56 . Notice that Δu(t) can be a varying value or a fixed value depending on the design of the MFA optimizer, which will be discussed in detail. This applies to all the Δu(t) value presented in this patent. At Block 58 , the routine waits for a period of time Tx. This is the estimated delay time between the process input and output, which is user-configurable. At Block 60 , the routine checks the measured process variable y(t) to see if its value is increased compared to previous values. If the answer is Yes, the routine goes to Block 62 to clear the Max_Count since it has not yet reached the maximum. The routine goes back to Block 52 to continue the search. If the answer at Block 60 is No, it means that y(t) was going up but now it is starting to decrease. It is a good indication that the maximum has been reached. At Block 64 , the current u(t) is saved as Umax, which is the optimizer output that produced maximum y(t). This step needs to be done only one time when Max_Count is equal to 0. Then the Max_Count is incremented by 1. At Block 66 , Max_Count value is checked. If it is larger than 2, it means that y(t) has been declining for the past 3 consecutive tries and it is certain that y(t) has passed its maximum. At Block 68 , the Max_Flag is set to ON to indicate the detection of maximum. Notice that the number of tries required to guarantee the detection of the maximum may depend on the process and is user configurable. Here, we use 3 tries as an example. It is a good idea to reset the u(t) to the saved Umax to allow y(t) to get back to its maximum. If the value of Max_Count is not larger than 2, the routine will go back to Block 52 to continue the search. FIG. 5 is a flow chart describing the steps in a minimum search engine mechanism in an MFA optimizer. At Block 70 , initialization is taking place including the tasks to clear the minimum counter (Min_Count) and minimum flag (Min_Flag). The counter and flag are variables in the minimum search engine mechanism. At Block 72 , the routine checks the process acting mode. If it is in the direct-acting mode, optimizer output u(t) is increased by Δu(t) at Block 74 . If it is in the reverse-acting mode, optimizer output u(t) is decreased by Δu(t) at Block 76 . At Block 78 , the routine waits for a period of time Tx. This is the estimated delay time between the process input and output, which is user-configurable. At Block 80 , the routine checks the measured process variable y(t) to see if its value has decreased in comparison to its previous values. If the answer is Yes, the routine goes to Block 82 to clear the Min_Count since it has not yet reached the minimum. The routine goes back to Block 72 to continue the search. If the answer at Block 80 is No, it means that y(t) was declining but now it is increasing. This is a good indication that the minimum has been reached. At Block 84 , the current u(t) is saved as Umin, which is the optimizer output that produced minimum y(t). This step needs to be done only one time when Min _Count is equal to 0. Then the Min _Count is incremented by 1. At Block 86 , Min_Count value is checked. If it is larger than 2, it means that y(t) has been rising for the past 3 consecutive tries and it is certain that y(t) has passed its minimum. Notice that the number of tries required to guarantee the detection of the minimum may depend on the process and is user configurable. Here, we use 3 tries as anxample. At Block 88 , the Min_Flag is set to ON to indicate the detection of the minimum. It is a good idea to reset the u(t) to the saved Umin to allow y(t) to go back to its minimum. If the value of Min_Count is not larger than 2, the routine will go back to Block 72 to continue the search. FIG. 6 is a flow chart describing the main search engine of an MFA optimizer. At Block 90 , initialization is taking place including the tasks to clear all counters, and set all default flags and parameters. At Block 92 , the process acting mode search routine is run to determine if the process is running in a direct-acting mode or reverse-acting mode. At Block 94 , the routine checks to see if the optimizer is searching for a minimum or maximum based on the status set by the Min/Max Setter. If searching for a minimum, the routine goes to Block 96 to run the Minimum Search routine. If it is searching for a maximum, the routine goes to Block 98 to run the Maximum Search routine. Once an optimal point is reached, the routine moves to Block 100 , where the user has the option of leaving the process running for a period of time, which can be set by the parameter Ty. During this quiet period, the MFA optimizer is in an idle mode with a fixed output u(t), leaving the process running at the optimal operating condition. This waiting period should be determined by the user. If the process is fast and dynamic, Ty may be set to a small value or even at zero seconds so that the search continues. If the process is relatively slow and steady, Ty can be set for a couple of hours or even days. The rule of thumb here is that the process should be running at its optimal operating condition as long as possible to maximize the economical benefits. There are several ways to design the MFA optimizer for generating its output u(t). Without losing generality, three design examples are provided. 1. MFA Controller-Based MFA Optimizer The SISO Model-Free Adaptive (MFA) controllers described in U.S. Pat. Nos. 6,055,524 and 6,556,980 B1 can be used to compute the MFA optimizer. When using this approach, the MFA optimizer can adapt to fit the changing process dynamics and/or operating conditions. The MFA optimizer produces its output u(t) in a similar way to a SISO MFA controller with varying value of u(t). In general, the output velocity limit (OVL) is used to clamp the output to keep it from making too big of a jump at each sample interval. That means, at each sample interval, the calculated Δu(t) is limited by the output velocity limit as described in the following formulas: Δ u ( t )=Δ u ( t ), if |Δ u ( t )|≦OVL  (1a) Δ u ( t )=SGN(Δ u ( t ))OVL, if |Δ u ( t )|>OVL  (1b) where SGN(.) denotes the sign function, SGN(Δu(t)) extracts the sign of Δu(t), and OVL>0 is the output velocity limit, which is user configurable. 2. PI Controller-Based MFA Optimizer A PI (proportional-integral) controller can be used to compute the output u(t). Since the derivative function of a PID controller will make the u(t) jump up and down, it cannot be used here. The standard PI algorithm has the following form: u ⁡ ( t ) = K p ⁡ [ e ⁡ ( t ) + 1 T i ⁢ ∫ e ⁡ ( t ) ⁢ ⅆ t ] , ( 2 ) where K p is the Proportional Gain, and T i is the Integral Time in second/repeat. Since we require a Δu(t), the following digital PI formula can be used. Δ u=K p {( e [2] −e [1])+( T s /T i ) e [2]}  (3) where Ts is the sample interval, e[1] and e[2] are the time sampled error signals of e(t), e[2] is the current sample of e(t). Similarly, the output velocity limit is used to clamp the output to keep it from making too big of a jump at each sample interval. 3. Output Step Limit Based MFA Optimizer A simple design for the MFA optimizer is to allow the user to configure an Output Step Limit (OSL). This is equivalent to the Output Velocity Limit (OVL) used in the feedback controller cases. Since the direction that u(t) is moving is already known by the search engines, we can simple let Δu ( t )=OSL,  (4) where OSL>0 is the user entered output step limit. That means, at each sample interval, u(t) will move up or down by Δu(t) which has the fixed value of OSL. The concept of the single-input-single-output (SISO) MFA optimizer can be expanded to multi-input-multi-output (MIMO) cases, which will be described in a future patent.
An apparatus and method is disclosed for solving optimization problems without the need to build mathematical models or rules. The inventive method combines the structure of a single-loop feedback control system and optimization search engine mechanisms. Running in real-time, a Model-Free Adaptive (MFA) optimizer can automatically search for the optimal operating point for a dynamic system when a parabolic relationship exists between the input and output. The MFA optimizer comprises a user-selected Min/Max setter to define the searching objective, a process acting-mode search engine to determine if the process is running in direct-acting or reverse-acting mode, a maximum search engine and a minimum search engine to find the maximum or minimum. This apparatus and method is useful in fuel-and-air ratio optimization for combustion processes, yield optimization for chemical or biological reactors, and operating efficiency optimization for coal or ore ball mills.
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CROSS REFERENCE TO RELATED APPLICATIONS The present application is a divisional of U.S. patent application Ser. No. 11/231,012, filed Sep. 20, 2005, now U.S. Pat. No. 7,214,896 entitled “ELECTRONIC APPARATUS HAVING ILLUMINATION BUTTON”, the content of which is expressly incorporated by reference herein in its entirety. Further, the present application claims priority from Japanese Patent Application No. 2004-284345, filed Sep. 29, 2004, which is also hereby incorporated by reference herein in its entirety. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation button to be illuminated of an electronic apparatus. 2. Description of the Related Art An electronic apparatus, such as digital camera, is often configured so that the operation buttons are all disposed on one face of the apparatus, and their associated switches are disposed on a single flexible board or a print board. Moreover, for a purpose of distinguishing buttons or identifying a button that indicates a specific function, a surface of the operation button is illuminated using a light source such as LED, which is emitted from the rear side of the button. The light source and the switch cannot both be placed right below the button. With regard to their positions, if the light source is not located in the center of the button, the button will not be evenly or efficiently illuminated. On the other hand, if the switch is not located in the center of the button, a satisfactory feeling of the button clicking cannot be obtained. With the advancement in recent years of the technology for producing thin electronic apparatuses, a space between the button and the light source or the switch is becoming smaller, and the above described problem is becoming more prominent. In small electronic apparatuses in recent years, if possible, the operation buttons tend to be situated in one place. The switches are frequently arranged on the flexible board or the print board, and disposed within a small space below a cover. In such a device, if a part of the operation buttons is configured to be illuminated, unevenness of illumination can easily occur if the LED is not located in the center of the button due to a space between the buttons, and because the board or flexible board on which the LED or the switches are mounted is so narrow. Moreover, there is a problem in that the amount of light decreases if the light originates from a light source placed away from the button. Moreover, because the tactile switch is thin, it has to be mounted on the large area so that the LED or the switch must be placed away from the center of the button. SUMMARY OF THE INVENTION One aspect of the present invention is directed to providing a structure when a plurality of operation members, including an illumination type operation member, is closely positioned. In one aspect of the present invention, an electronic apparatus includes a first operation button, a second operation button, a first board mounted with a first switch corresponding to the first operation button, wherein a portion of the first board, a second switch corresponding to the second operation button, wherein the second switch is mounted below the notched portion of the first board, and a light source mounted below the second operation button. In another aspect of the present invention, an image capture device includes an image capture unit, a display unit that displays am image obtained from the image capture unit, wherein the display unit is mounted on a first side of a rear portion of the image capture unit, a first operation button mounted on a second rear portion located opposite to the first rear side, a second operation button mounted on the second rear side located opposite to the first rear side, a first board mounted with a first switch corresponding to the first operation button, wherein the first board is notched in part, a second switch corresponding to the second operation button, mounted below the notched portion of the first board, and a light source mounted below the second operation button. Further features of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. FIG. 1 is an exploded perspective view showing a camera according to a first embodiment of the present invention viewed from the front side. FIG. 2 is an exploded perspective view showing the camera according to the first embodiment of the present invention viewed from the rear side. FIG. 3 is a drawing showing a cross sectional view of the illumination button and its surroundings according to the first embodiment. FIG. 4 is a drawing showing a cross sectional view of the illumination button and its surroundings according to the second embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS Embodiments of the invention will be described in detail below with reference to the drawings. First Exemplary Embodiment FIG. 1 is an exploded perspective view of a camera according to one embodiment of the present invention, where the view is from front side of the camera. FIG. 2 is an exploded perspective view of the camera according to one embodiment of the present invention, where the view is from the rear side of the camera. Referring to these drawings, a front cover 1 covers the front side of the camera, and a rear cover 2 covers the rear side. A lens barrel unit 3 holds an image taking lens and the like in which a finder unit 4 , a zoom motor 5 that rotates the lens barrel unit, and a gear unit 6 are integrally assembled, and is fixed to a base member 8 by screws 7 a , 7 b , and 7 c. The battery case 9 holds a battery 51 , which is fixed to the base member 8 with screws 11 a and 11 b inserting the power source board unit 10 in between. Reference numeral 12 denotes a strobe unit on the upper part of which a strobe flash unit 13 is arranged. A flexible board 14 for a strobe that mounts to a strobe circuit thereon is attached to a frame portion of the strobe unit 12 which extends to a lower part. A strobe capacitor 15 is also fixed to the frame portion of the strobe unit 12 . The strobe unit 12 is disposed in front of the zoom motor 5 and the gear unit 6 attached to the lens barrel unit 3 , which is fixed to the base member 8 by a screw 16 in the side portion. A width of the strobe flash unit 13 is approximately equal to the combined width of the gear unit 6 and the zoom motor 5 disposed in its back, accordingly they can be arranged with no wasted space. Reference numeral 17 denotes a main board on which the CPU, the memory, the image processing LSI, and the like, are mounted. A slot 17 a of the SD memory card 17 b (external memory) and a USB connector 17 c are mounted on the rear side of the main board 17 . The main board 17 is fixed to the base member 8 and the battery case 9 by screws 18 a , 18 b , and 18 c . Reference numeral 19 denotes an operation flexible board on which a release switch, a power switch, and the like are mounted. Reference numeral 20 denotes a speaker which terminal is soldered to one edge of the operational flexible board 19 . An operation button base 21 is made of silicon rubber to which the operation buttons such as cross key 22 , center key 23 , or push buttons 24 and 25 are attached. At the rear side of this operation button base 21 , dome-shaped metallic plates (metal domes) are attached to positions corresponding to each of the buttons stuck on the operation button base 21 . By pressing each operation button, the metal dome is brought into contact with a pattern on the operation flexible plate 19 and energization is performed. Moreover, a portion 21 a of the operation button base 21 covers an edge of the speaker 20 and plays a role of the cushion by filling in a gap between the speaker 20 and the rear cover 2 . Reference numeral 26 denotes an illumination button to which a light guiding member 27 is attached at the center. An LCD holder 30 holds an LCD panel 29 and a back light (not shown), and is fixed to the base member 8 by a screw 31 . A mode switching button 32 switches the operation mode of the camera to a still picture image taking mode, a moving picture image taking mode, or a replaying mode by sliding in a right and left direction as shown in FIG. 2 . The mode switching button 32 is configured to be capable of moving from side to side, sandwiching the rear cover 2 together with a fixing board 33 located at its rear side. In addition, the mode switching button 32 is configured to enable the switch unit to perform switching with a notch 33 a , which holds an arm of the mode switching button 32 mounted on the operation flexible board 19 . A button holding member 34 holds a zoom dial 35 , a release button 36 , and a power button 37 and is disposed above the battery case 9 across the operational flexible board 19 . Moreover, the button holding member 34 has on its side a USB connector 17 c and a jack storing unit that stores a jack (not shown) for images and sounds, as well as a pull-out type jack cover 38 that covers them. Reference numeral 41 denotes a strap attaching member of a rectangular shape with a round surface to which a strap 42 is attached. From the standpoint of design and strength, the strap attaching member 41 is formed by die casting. The strap attaching member 41 has an opening 41 b . An end of the strap ring 42 is wounded around a rod-shaped unit 41 a which crosses nearly the center of the opening 41 b . The strap attaching member 41 has screw holes punched approximately in an elongated direction of the rod-shaped unit 41 a . The screw holes are used to mount the strap attaching member 41 on the base member 8 by the screws 44 a and 44 b . Thereby, the force pulling the strap attaching member 41 caused by the strap 42 is efficiently transmitted to the camera body. Reference numeral 43 denotes an inner member having an arc-shaped (or hemisphere) recess 43 a . The inner member 43 is fitted to the opening unit 41 b of the strap attaching member 41 from the rear side. When the inner member 43 is fitted to the strap attaching member 41 , the recess 43 a and the opening 41 b form a hole under the rod-shaped unit 41 a which guide an end 42 a of the strap 42 from one side of the opening 41 b to the other side. Reference numeral 45 denotes a tripod securing member where a screw is cut to secure a tripod. FIG. 3 shows the cross sectional view of the illumination button 26 and its surroundings. As shown in FIG. 3 , the operational flexible board 19 and the operation button base 21 are sandwiched and held by the base member 8 and the rear cover 2 . A push button 25 is attached on top of the operation button base 21 , and a metal dome 25 a adheres on its rear side. Other push buttons 24 , the cross key 22 , and the center key 23 are similarly arranged (not shown in FIG. 3 ). The illumination button 26 is arranged by notching a part of the operational flexible board 19 . A tactile switch 10 a is mounted on the power source board unit 10 located further inside the camera than the flexible board 19 and is configured to be pressed by an edge 27 a of the light guiding member 27 . An LED 10 b is disposed at a side of the tactile switch 10 a , and a light emitted from the LED 10 b is guided to the surface of the illumination button 26 through the light guiding member 27 . Although the LED 10 b is located slightly off-center of the illumination button 26 , it is capable of irradiating the surface of the illumination button 26 uniformly and efficiently because of its position with respect to the surface of the illumination button 26 . Moreover, since the tactile switch 10 a does not require a large mounting area, the center of the tactile switch 10 a can be placed close to the center of the illumination button 26 , thus keeping the LED 10 b close to the center of the illumination button 26 . A base of the illumination button 26 is fixed to the base member 8 by a screw 28 . Second Exemplary Embodiment FIG. 4 shows the cross sectional view of the illumination button 126 and its surroundings according to the second embodiment. All other elements of the camera have the same configuration as shown in FIGS. 1 and 2 . As shown in FIG. 4 , the operational flexible board 119 and the operation button base 121 are sandwiched and held by the base member 108 and the rear cover 102 . A push button 125 is attached on the operation button base 121 , and a metal dome 125 a adheres to its rear side. The illumination button 126 has a U-shaped switch (SW) pressing unit 126 a , and a light guiding member 127 is attached to the button 126 center. A tongued unit 108 a of the base member 108 is inserted into the inside of the switch pressing unit 126 a . An LED 110 b is disposed immediately below the light guiding member 127 . Moreover, a tactile switch 110 a is mounted on the power source board unit 110 which is located further inside the camera than the operational flexible board 119 , and configured to be pressed by the switch pressing unit 126 a . A light emitted from the LED 110 b is guided to the surface of the illumination button 126 through the light guiding member 127 in an upward direction from the tactile switch 110 a. According to the first embodiment, a plurality of buttons is disposed in the vicinity of one face of the camera, and a part of the buttons is illuminated with light from a light source, such as an LED, from behind the buttons so as to allow them to light up. In that case, if the light source is disposed further inside than the switches of the buttons, and the part of the button surfaces is illuminated using the light guiding member, the buttons can be illuminated efficiently and with good appearance since the light source is located almost immediately below the button. Moreover, according to the second embodiment, a switch is located further inside than the light source, and the light source is placed between the switch and the light guiding member. Accordingly, the buttons can be illuminated efficiently and with good appearance. Further, according to the present embodiments, only the center of the illumination button 26 ( 126 ) is illuminated so that the light guiding member is configured as a separate member. However, the illumination button 26 ( 126 ) and the light guiding member 27 ( 127 ) may be integrally molded and other unnecessary surfaces may be screened with a paint, and the like, or the whole button 26 ( 126 ) may be illuminated while it is integrally molded. While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures and functions.
An electronic apparatus with an illuminated button, the apparatus comprising a first operation button, a second operation button, a first board mounted with a first switch corresponding to the first operation button, wherein a portion of the first board is notched, a second switch corresponding to the second operation button, wherein the second switch is mounted below the notched portion of the first board, and a light source that is mounted below the second operation button.
7
TECHNICAL FIELD This invention relates to a method and apparatus for dispersing fiber clumps, e.g. cotton boll clumps, from two or more textile fiber modules, e.g. cotton boll modules, at the same time, and mixing the clumps to form a blend, and to a method and apparatus for mixing particulate materials, e.g. wood chips. BACKGROUND OF THE INVENTION Below there is a description of the handling of cotton fibers, starting with the harvesting of cotton bolls. However, the invention is not limited to the handling of cotton fibers but rather applies equally as well to the handling of other textile fibers that have been compressed into large modules that need to be mechanically dispersed into clumps of fibers so that the fibers can be separated, cleaned and then further processed, ultimately into yarns. It also applies to mixing particulate materials, e.g. wood chips. As known to those skilled in the art, cotton plants produce seedpods, known as cotton bolls, which contain the seeds. Seed hairs, or fibers, growing from the outer skin of the seeds, become tightly packed within the boll, which bursts open upon maturity, revealing soft masses of the fibers. These fibers are white to yellowish white in color, range from about 0.75 to about 1.5 inches in length and are composed of about 85-90% cellulose, a carbohydrate plant substance; five to eight percent water; and four to six percent natural impurities. Cotton is harvested when the bolls open. In the fields, the cotton bolls are tightly compressed into large modules which are transported from the fields to processing plants. In the processing plants, the modules are mechanically dispersed into clumps of bolls and then the fibers are separated from the seeds and are cleaned and then are further processed, ultimately into yarns. It is known to disperse the cotton boll modules by use of a stack of rolls that include fingers which rotate into an advancing end of a cotton module, to tear loose clumps of the bolls from the module as they rotate. The stack of rolls is termed a disperser and it is common to use conveyors for delivering the cotton modules to the disperser. Example disperser systems are disclosed by the following United States Patents: U.S. Pat. No. 4,497,085, granted Feb. 5, 1985 to Donald W. Van Doorn, James B. Hawkins, Tommy W. Webb and William A. Harmon, Jr.; U.S. Pat. No. 5,121,841, granted Jun. 16, 1992, to Keith Harrington and Donald Rogers; U.S. Pat. No. 5,222,675, granted Jun. 29, 1993, to Jimmy R. Stover; U.S. Pat. No. 5,340,264, granted Aug. 23, 1994, to Manfred W. Quaeck and U.S. Pat. No. 5,469,603, granted Nov. 28, 1995, to Jimmy R. Stover. These patents show examples of the conveyors which have been used, or proposed, for delivering the cotton modules to the disperser. The present invention is not limited to any particular type of conveyor. However, a reciprocating slat conveyor is preferred. Example reciprocating slat conveyors that are suitable are disclosed by U.S. Pat. No. 5,934,445, granted Aug. 10, 1999, to Raymond Keith Foster, Randall M. Foster and Kenneth A. Stout, and U.S. Pat. No. RE 35,022, granted Aug. 22, 1995, to Raymond Keith Foster. Cotton fibers, for example, may be roughly classified into three main groups, based on staple length (average length of the fibers in a cotton module) and appearance. The first group includes the fine, lustrous fibers with staple length ranging from about 1 to about 2.5 inches and includes types of the highest quality—such as Sea Island, Egyptian and Pima cottons. Least plentiful and most difficult to grow, long-staple cottons are costly and are used mainly for fine fabrics, yarns and hosiery. The second group contains the second group contains the standard medium-staple cotton, such as American Upland, with staple length from about 0.5 to 1.3 inches. The third group includes the short-staple, coarse cottons, ranging from about 0.375 to 1 inch in length, used to make carpets and blankets, and to make coarse and inexpensive fabrics when blended with other fibers. Within each group, the quality of the fibers can vary depending on such things as where the cotton is grown. It is desirable to blend the lower quality fibers with higher quality fibers to produce an acceptable quality blend of fibers. It is an object of the present invention to provide a method and apparatus for blending cotton clumps as they are removed from the cotton modules. The clumps of bolls are mixed together to form the blend and then the blend is further processed to separate the fibers from the seeds, etc. Another object of the present invention is to provide a method and apparatus for blending other types of textile fiber clumps as they are removed from the textile fiber modules. Clumps from different modules are mixed together to form a blend of the fibers and then the blend is conveyed on for further processing. It is yet another object of the invention to provide a method and apparatus for mixing particulate materials, such as different types and/or grades of wood fiber chips, and wood fiber chips with other materials, e.g. granule recycled plastic. BRIEF DESCRIPTION OF THE INVENTION One apparatus of the present invention is basically characterized by a pair of confronting dispersers, each having an input side and an output side. The output sides of the two dispersers face each other on opposite sides of a mixing zone. A feed conveyor is provided for each disperser. Each feed conveyor is adapted to feed textile fiber modules into the input side of its disperser. An output conveyor is positioned between the two dispersers, at the bottom of the mixing zone. The feed conveyors are adapted to move the modules to the dispersers. Each disperser removes fiber clumps from its module and discharges them airborne into the mixing zone into admixture with fiber clumps delivered airborne into the mixing zone from the other disperser. The mixed blend of fiber clumps falls on the outfeed conveyor and the output conveyor carries the blend away from the mixing zone. Each disperser comprises a plurality of power driven rolls, each of which is supported for rotation about a horizontal axis and includes a plurality of fingers that move into and then out from the module as the rollers rotate. The fingers are adapted to remove fiber clumps from the module and project them into the mixing zone. Preferably, the output conveyor extends generally perpendicular to the two feed conveyors. Preferably also, the feed conveyors are reciprocating slat conveyors. The outfeed conveyor may be an endless belt conveyor. According to an aspect of the invention, the apparatus may comprise first and second pairs of confronting dispersers of the type described, each disperser having its own feed conveyor. The output conveyor picks up a blend of fiber clumps from the first mixing zone and moves the blend onto the second mixing zone where a second blend of fibers and fiber clumps is deposited onto the cotton boll clump already on the output conveyor. The method of the present invention is basically characterized by positioning first and second dispersers at a disperser station, in a spaced apart confronting relationship, so as to define a mixing zone between them. The first and second dispersers are operated while a first module is fed into the first disperser and a second module is fed into the second disperser. The first and second dispersers are operated so that each will disperse fiber clumps from its module and deliver them into the mixing zone in admixture with the fiber clumps from the other disperser. The mixture of fiber clumps is collected at the bottom of the mixing zone and is carried away from the disperser station. Another aspect of the invention is to feed the modules against the dispersers by use of conveyors and controlling the feed rate by controlling the conveyor speed. A further aspect of the invention is to provide third and fourth dispensers at the dispenser station, also in a spaced apart confronting relationship, so as to define a second mixing zone between them. The third and fourth dispersers are operated while a third textile fiber module is fed into the third disperser and a fourth textile fiber module is fed into the fourth disperser. The third and fourth dispersers are operated so that each will disperse fiber clumps from its module and deliver them into the second mixing zone in admixture with the fiber clumps from the other disperser of the pair. The mixture of fiber clumps is collected at the bottom of the second mixing zone, on top of the mixture of fiber clumps from the first mixing zone, and the total mixture is carried away from the disperser station. Yet another aspect of the invention is to provide an improved disperser roll construction. According to this aspect of the present invention, the disperser roll is provided with an elongated tubular core. At least two axially spaced apart disks are provided in the tubular core. A plurality of elongated tooth support members are spaced around the tubular core. Each tooth support member has an inner portion contacting the core and an outer portion spaced radially outwardly from the core. Each tooth support member is connected to the spaced apart radial disks. A plurality of generally radially outwardly extending teeth are secured to the outer portion of each tooth support member. Preferably, each tubular core has opposite ends and the disperser roll has support shafts projecting outwardly from the opposite ends of the tubular core. Preferably also, the disperser roll has at least three axially spaced apart radial disks on the tubular core, dividing the core into at least two axial sections. The elongated tooth support members for each section are spaced angularly in position relative to the tooth support members for the other section. In preferred form, the disperser roll comprises four axially spaced apart radial disks on the tubular core, dividing the core into three axial sections. The elongated tooth support members for each section are angularly spaced in position from the tooth support members of the adjacent section. In preferred form, the teeth are detachably secured to the outer portions of the tooth support members. Also, in preferred form, the elongated tooth support members are angle iron members. The inner portion is an inwardly extending first leg of the angle iron member and the outer portion is chordwise extending second leg of the angle iron member. A still further aspect of the invention is to provide a system which includes two dispersers in a disperser tunnel or four dispersers in two disperser tunnels, and a feed conveyor for each disperser that is at the bottom of an elongated storage bin for a particulate material, e.g. wood chips or the like. In use, the conveyors feed the particulate material to the dispersers. The disperser of each pair picks up particles from the particulate material in its bin and propels them towards the other disperser. The particles from the two dispersers meet and mix within a mixing zone that is located between the dispersers. An outfeed conveyor at the bottom of the mixing zone collects the mixed particles and removes them from the disperser station. Other objects, advantages and features of the invention will become apparent from the description of the best mode set forth below, from the drawings, from the claims and from the principles that are embodied in the specific structures that are illustrated and described. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS Like reference numerals and letters refer to like parts throughout the several views of the drawing, and: FIG. 1 is a pictorial view of a mature cotton boll, showing how it appears when harvested; FIG. 2 is a pictorial view of apparatus according to the present invention for dispersing clumps of cotton bolls from a plurality of cotton modules and mixing them together for delivery to the next stage of processing, such view being taken from above and looking towards the top, one side and one end of the apparatus; FIG. 3 is a diagrammatic sectional view through the center region of the apparatus shown by FIG. 2, showing a mixing zone formed by and between two dispersers, and an output conveyor below the mixing zone; FIG. 4 is a view similar to FIG. 3, but showing two pairs of dispersers, a mixing zone between the dispersers of each pair, and including a schematic diagram of a computer controlled system for controlling the speed rate of the conveyors that deliver the cotton modules to the dispersers; FIG. 5 is a side elevational view of one of the disperser rollers; FIG. 6 is an enlarged scale fragmentary view of the roller shown by FIG. 5; FIG. 7 is a sectional view taken substantially along line 7 — 7 of FIG. 6; FIG. 8 is a sectional view taken substantially along line 8 — 8 of FIG. 6; FIG. 9 is a fragmentary view looking towards one side of one of the disperser tunnels, such view showing the two end halves of the disperser tunnel moved apart and a baffle positioned in the center of the mixing zone, between the two dispersers, such view also showing how the disperser rolls and drive motor are mounted on the frame of the disperser tunnel; FIG. 10 is a sectional view taken substantially along line 10 — 10 of FIG. 9, such view including a drive train diagram showing how the disperser rolls are connected to the drive motor; and FIG. 11 is a view like FIG. 2, but showing the feed conveyors provided with sidewalls so as to define storage bins in which particulate material is stored. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a pictorial view of a single cotton boll substantially as it appears at harvest time. The boll 10 comprises a stem 12 , a base 14 connected to the stem 12 and a ball of seed hairs, or fibers, growing from the outer skin of seeds that are within the boll 10 . In a manner that is well known in the art, the cotton bolls 10 are removed from the cotton plant and are tightly compressed into large modules 18 , 18 ′, 18 ″, 18 ′″ that are removed from the field and transported to the processing plant. FIG. 2 shows a disperser station at a processing plant that incorporates the present invention. This disperser station comprises a pair disperser tunnels 20 , 22 each including a pair of confronting dispersers 24 , 26 and 28 , 30 . Each disperser, 24 , 26 , 28 , 30 is provided with its own conveyor 32 , 34 , 36 , 38 . In the illustrated system, the conveyors 32 , 34 , 36 , 38 are reciprocating slat conveyors. FIG. 3 is a longitudinal sectional view of disperser tunnel 20 and its two dispersers 24 , 26 . In FIG. 3, the structure is somewhat schematically shown as the constructional details of the tunnel 20 is not particularly important to the present invention. FIG. 3 shows conveyor 32 positioned and arranged to feed the modules 18 , 18 ′, 18 ″, 18 ′″ into the input sides of the dispersers 24 , 26 , respectively. In this embodiment, the dispersers 24 , 26 are identical and each comprises a plurality of disperser rolls 40 . In each disperser 24 , 26 , the bank of rolls 40 lean to the rear from vertical. A lean angle x (FIG. 9) of about thirty degrees (30°) is illustrated. A mixing zone 42 in the shape of an inverted trapezoid is defined by and between the two dispersers 24 , 26 and below the top of the disperser tunnel 20 . Mixing zone 42 includes a lower portion 44 situated below the conveyors 32 , 34 and above the upper run 50 of an outfeed conveyor 52 . Mixing zone portion 44 includes sidewalls 46 , 48 that slope downwardly from the conveyors 32 , 34 to the upper run 50 of the conveyor 52 . FIG. 4 shows a schematic of the disperser tunnel 22 below the schematic of the disperser tunnel 20 . In FIG. 4, a mixing zone 54 is shown between the two dispersers 28 , 30 and below the top of the mixing tunnel 22 . Mixing zone 54 is in series with mixing zone 42 and it shares the same outfeed conveyor 52 and the same sidewalls 46 , 48 . At times, it may be desirable to use a single disperser (e.g. disperser 24 ) in a single disperser tunnel (e.g. tunnel 20 ), in which case the associated conveyor (e.g. conveyor 32 ) will be operated to move modules 18 into the dispersing tunnel and against the rolls 40 of the disperser 24 . Preferably, when a single disperser is used, a baffle B is positioned at the center of the disperser tunnel 20 . As shown by FIGS. 2, 9 and 11 , each disperser tunnel 20 , 22 may be constructed in two longitudinal halves. In FIG. 9, the two halves are shown spaced apart. This is so that a baffle B can be included in the view. Preferably, the two tunnel parts are connected together and a slot is provided in the top of the assembly where the two parts meet. The slot leads into vertical slideways that are positioned to collect opposite side edge portions of the baffle B. A top plate 31 may extend along the upper edge of the baffle B. One or more handles H may be secured to the plate 31 . In use, when it is desired to use only a single disperser, e.g. disperser 24 , in a single disperser tunnel, e.g. tunnel 20 , a workman need only pick up the baffle B by use of the handle or handles H. The lower edge of the baffle B can be dropped into the slot provided at the top of the tunnel. Then, the baffle B may be allowed to move downwardly under the influence of gravity until the top plate 31 is on top of the disperser tunnel, overlying the top and the slot and portions of the tunnel top that immediately border the slot. Whenever it is desired to use both dispersers at once, the workman need only grab the handle or handles H and pull the baffle B up out of the slideways and set it to one side of course, other ways may be used for providing a baffle B at the center of the mixing zone. When the baffle B is in place, the fiber clumps that are being thrown into the mixing zone by the disperser that is operating will strike the baffle B and then drop downwardly onto the outfeed conveyor 52 . As will hereinafter be described in greater detail, rotation of the disperser rolls 40 will move fingers into the module 18 that will dislodge clumps of cotton bolls from the front end of the module 18 . As the fingers move into, then through, and then out from the module 18 , they form the clumps and then throw the clumps into the chamber 42 . The clumps then fall by gravity onto the upper run 50 of the outfeed conveyor 52 . The output conveyor 52 then moves the clumps on to the next station in the processing plant. Herein, the term “cotton boll clumps” includes a single cotton boll, a portion of a single cotton boll, a plurality of cotton bolls, and one or more cotton bolls stuck together by themselves or with any portion or portions of one or more additional cotton bolls. The term “textile fiber clumps” means the same thing but also includes other textile fiber materials. Referring again to FIG. 3, at times it may be desired to remove cotton boll clumps from two modules 18 , 18 ′ at the same time, by operating both conveyors 32 , 34 at the same time. Conveyor 32 is operated to move a module 18 into the input of disperser 24 while conveyor 34 is operated to move a module 18 ′ into the input of disperser 26 . When this is done, the cotton clumps from the two modules 18 , 18 ′ are mixed together in the mixing zone 42 . In FIG. 3, broken lines are used to show the travel paths of the cotton boll clumps. Mixing occurs as the cotton boll clumps are propelled (viz. moved airborne) into the mixing zone 42 so it can be said that each disperser 24 , 26 removes cotton boll clumps from its module 18 , 18 ′ and discharges them into the mixing zone 42 into admixture with the cotton boll clumps from the other dispenser 24 , 26 . When both conveyors 32 , 34 and both dispersers 24 , 26 are operated, a blend of cotton boll clumps is formed in the mixing zone 42 . This blend drops onto the upper run 50 of the outfeed conveyor 52 . As will be appreciated, the two conveyors 32 , 34 can be operated at either substantially the same feed rate or at different feed rates. When operating them at substantially the same feed rate, the blend will comprise approximately 50% cotton boll clumps from module 18 and 50% cotton boll clumps from module 18 ′. Or, the feed rate of the conveyors 32 , 34 may be different. For example, conveyor 32 may be operated to cause travel twice as fast as conveyor 34 . In this event, the blend or mixture will comprise two parts cotton boll clumps from module 18 and one part cotton boll clumps from module 18 ′. Referring again to FIG. 4, it may be desirable to mix together cotton boll clumps from three grades or types of module. For example, conveyors 32 , 34 and 36 may be operated at the same time, each at substantially the same feed rate or at different feed rates. In this mode of operation, a baffle B will be inserted between disperser 28 , 30 . The cotton boll clumps that are dispersed from disperser 28 strike the baffle B and then fall down and are deposited onto the blend of cotton boll clumps from dispersers 24 , 26 that is on the upper run 50 of the conveyor 52 . The system also permits the mixing together of cotton boll clumps from four distinct modules. This is done by utilizing all four conveyors 32 , 34 , 36 , 38 for simultaneously feeding four modules 18 , 18 ′, 18 ″, 18 ′″, each with a different quality content. Operation of conveyers 32 , 34 and dispersers 24 , 26 will admix cotton boll clumps from modules 18 , 18 ′. They will drop down onto the upper run 50 of the conveyor 52 . Operation of conveyors 36 , 38 and dispersers 28 , 30 together will admix cotton boll clumps from modules 18 ″, 18 ′″. This mixture will drop on the mixture of cotton boll clumps from modules 18 , 18 ′ which is already on the upper run 50 of the conveyor 52 . FIG. 4 shows a schematic diagram of a control system that includes a programmed computer 56 that is adapted to send control signals to feed control devices 58 , 60 , 62 , 64 associated with the conveyors 32 , 34 , 36 , 38 . The control system disclosed in the aforementioned U.S. Pat. No. 5,934,445 includes a programmable processor or computer and circuit components for varying the feed rate of the conveyor. It is within the skill of the art for a programmer to adapt the processor 56 so that it can be used for controlling the feed rates of the four conveyors 32 , 34 , 36 , 38 . The processor 56 can be programmed to select how many of the conveyors 32 , 34 , 36 , 38 will be used at a given time, and the feed rate of each conveyor. It can also be programmed to turn the dispersers 24 , 26 , 28 , 30 on and off, and also control the speed rate of the rollers 40 . Keith Manufacturing Company of 401 N.W. Adler, Madras, Oreg. 97741, makes a conveyor known as the “Running Floor II®” unloading system or unloader. This system controls the feed rate of the conveyor by controlling the output of the pump that delivers hydraulic fluid to the hydraulic cylinders that move the conveyor slats. The pump output is controlled by controlling revolutions per minute of the tractor motor that drives the pump. In the system of FIG. 4, the conveyors 32 , 34 , 36 , 38 can be Running Floor II® conveyors. The processor 56 can be programmed to vary the drive input to the pump or in another suitable way, vary the flow rate of hydraulic fluid to the hydraulic cylinders that move the conveyor slats. Various ways may be used to determine the feed rate of fiber. clumps into the mixing zones. For example, it can be calculated from knowing the cross sectional dimensions of the module and the conveyor speed: Also, sensors may be provided along the path of travel of each module and used to determine movement of a particular part of the module over a particular amount of time. Each module may be provided with a mark on its side or top and the sensors may be positioned to monitor the position of this mark. The information received from the sensors can then be fed to the control system, as a feedback system, and used for changing the speed rate of the conveyor. FIGS. 5-8 show a preferred construction of the disperser roll 40 , also termed the “spike roll”. This construction is quite simple but yet provides a very sturdy, durable roller. In preferred form, roller 40 includes an elongated tubular core 60 that extends substantially the full length of the main body of the roll. Core 60 is mounted for rotation by a live shaft 62 having end portions 64 , 66 that extend axially outwardly of the opposite ends of the core 60 . The core tube 60 may be supported on the member or members that provide the live shafts 64 , 66 in any suitable manner, such as by use of disks or spiders that project radially outwardly from the members 64 , 66 to the core tube 60 . Members 64 , 66 may be opposite end portions of a continuous member that extends all the way through the core tube 60 . Or, they may be shorter members that are connected to the opposite end portions of the tubular core member 60 . According to the present invention, the roll is divided into a plurality of sections by radial disks. In the illustrated embodiment, four disks 68 , 70 , 72 , 74 are used. They divide the roll 40 into three sections that may be of substantially the same length or their lengths may vary to some extent. The disks 68 , 70 , 72 , 74 may have a circular outline and may include a circular center opening through which the core tube 60 extends. The disks 68 , 70 , 72 , 74 may be welded to the core tube 60 . The live shaft end portions 64 , 66 are mounted for rotation in bearings. Shaft end portion 66 is connected to a suitable drive device for rotating the shaft portion 66 , and hence, the roll 40 . Bearing support systems and drive systems for disperser rolls are known in the prior art and do not per se form a part of the present invention. According to the present invention, a plurality of elongated tooth support members 76 , 78 , 80 are spaced around the tubular core, as shown by FIGS. 6 and 7. By way of typical and therefore non-limitive example, there are four members 76 , four members 78 , and four members 80 . As shown by FIGS. 7 and 8, the two support members for each section are angularly spaced in position from the two support members of the adjacent section. In FIG. 7, the two support members 76 are shown at north, east, south and west positions. In FIG. 8, the two support members are shown in northeast, southeast, southwest and northwest positions. The two support members 80 are in axial alignment with the two support members 76 . In other words, they are also in north, east, south and west positions and the 76 , 78 are in the positions shown by FIGS. 7 and 8. In preferred form, each tooth support member 76 , 78 , 80 is a length of angle iron. The angle iron members 76 , 78 , 80 are positioned such that they present an inner leg that preferably contacts the core tube 60 and an outer leg. The outer leg is substantially perpendicular to the inner leg and extends chordwise of the disks 68 , 70 , 72 , 74 . The inner leg is perpendicular to the outer leg but does not extend radially. The opposite ends of the two support members 76 , 78 , 80 are welded or otherwise firmly connected to the disks 68 , 70 , 72 , 74 . Each tooth support member 76 , 78 , 80 supports a plurality of teeth or “spikes” 82 that are detachably connected to the outer leg of the tooth support member 76 , 78 , 80 . The teeth or spikes 82 may be in the form of rods provided with a threaded connection 84 where they are connected to the tooth support members 76 , 78 , 80 . As will be apparent, the angular staggering of the tooth support members 76 , 78 , 80 results in an angular staggering of the teeth 82 in the center section relative to the teeth 82 in the two end sections. Referring to FIGS. 9 and 10, the disperser roll shafts 64 , 66 are mounted onto frame portions of the tunnel structure 20 , 22 by bearing assemblies that are shown in FIG. 9 . Preferably, the tunnel structure includes diagonal frame members, one of which is designated 150 in FIG. 9 . It also includes bottom rails, one of which is designated 152 in FIG. 9 . In the illustrated embodiment, the bearing blocks for the upper five disperser rolls 40 are bolted to the frame member 150 . The bearing block for the lowest disperser roll 40 is bolted to the bottom of frame member 152 . The bearing block for the disperser roll 40 that is second from the bottom is bolted to the top of frame member 152 . For each disperser 24 , 26 , 28 , 30 a drive motor 154 is mounted on top of the disperser tunnel. As shown in FIG. 10, a drive belt assembly 156 may connect an output pulley 158 on motor 154 to a pulley 160 that is connected to end shaft 64 of the center disperser roll 40 . In the illustrated embodiment, there are seven disperser rolls 40 . Thus, there are three disperser rolls 40 above and three disperser rolls 40 below the center disperser roll 40 . By way of typical and therefore non-limitive example, the drive belt assembly may comprise five vee belts. As also shown by FIG. 10, at the opposite ends of the disperser rolls 40 , pulleys are connected to the end shaft 66 of the disperser rolls 40 . Drive belts 162 , 164 , 166 , 168 , 170 , 172 interconnect adjacent pulleys. The pulley on end shaft 66 for the center disperser is connected to both the pulley on the end shaft 66 above it and the pulley on the end shaft 66 below it. The connection pattern of the pulleys 162 , 164 , 166 , 168 , 170 , 172 is shown in FIG. 10 . Preferably, the belts are cogged belts or are timing belts. The belt and pulley drive system that is illustrated operates to rotate the disperser rolls 40 in the same direction and at substantially the same speed. The direction may be either clockwise or counterclockwise. The speed may be a variable speed that is determined by the output of motor 154 . That is, a variable speed motor 154 may be used. Or, the motor may include a variable speed output transmission. FIG. 11 shows a modified system of the present invention. In this system, the disperser tunnels 20 , 22 , the dispersers 24 , 26 , 28 , 30 , the feed conveyors 32 , 34 , 36 , 38 may all be the same as their counterparts in FIGS. 2-10. The only difference is that the conveyors 32 , 34 , 36 , 38 have been provided with sidewalls for the purpose of defining storage bins above each feed conveyor. Feed conveyor 32 is provided with sidewalls 90 , 92 that along with the conveyor 32 form a storage bin 106 . Conveyor 34 and sidewalls 94 , 96 form a storage bin 108 . Conveyor 36 and sidewalls 98 , 100 form storage bin 110 . Conveyor 38 and sidewalls 102 , 104 together form a storage bin 112 . In this embodiment, particulate material is placed in the storage bins 106 , 108 , 110 , 112 . The particulate material may extend partway up or all the way up to the tops of the dispersers 24 , 26 , 28 , 30 . Broken lines are shown in FIGS. 3 and 4 at about the level of the uppermost disperser roll 40 in the dispersers 24 , 26 , 28 , 30 . The particulate material may extend up to this broken line. Or, the height of particulate material in the storage bins 106 , 108 , 110 , 112 may be at some level below the broken lines. As in the case of the textile fibers, two, three or all four of the disperser units may be used together for the purpose of mixing or blending different kinds or grades of particulate material in the several storage bins 106 , 108 , 110 , 112 . For example, conveyors 32 , 34 may be operated for delivering particulate material to the input sides of the dispersers 24 , 26 . As shown in FIGS. 3 and 4, the dispersers may function to dislodge particles from the bodies of particles in the storage bins 106 , 108 and propel them into the mixing zone 44 , so as to form a blend or mixture that then gravitates onto the upper run 50 of the outfeed conveyor 52 . A third conveyor, e.g. conveyor 36 , may be operated to deliver additional particulate material to disperser 28 and disperser 28 may be used for feeding particles of such particulate material into the mixing zone 54 , preferably against the baffle B. These particles will then fall down onto the blend of particles that is on the upper run 50 of the conveyor 52 . When all four units are used, the particle material delivered by conveyors 36 , 38 from storage bins 110 , 112 are fed into the dispersers 28 , 30 . The disperser rolls 40 remove particles from the bodies of particulate material that are being fed to the dispersers 28 , 30 and propel such particles into the mixing zone 42 . The mixture or blend then falls down onto the mixture or blend of particles from dispersers 24 , 26 that are already on the upper run 50 of the conveyor 52 . The system is usable for measuring and mixing any types of particles that one may want to mix. Different sizes or kinds of wood chips may be mixed. Wood chips may be mixed with coal is particles, and then the mixture compressed into logs to be used as fuel. Or, wood chips can be mixed with plastic chips. Or different sizes and kinds of plastic chips can be mixed together. The illustrated embodiments are only examples of the present invention and, therefore, are non-limitive. It is to be understood that many changes in the particular structure, materials and features of the invention may be made without departing from the spirit and scope of the invention. Therefore, it is my intention that my patent rights not be limited by the particular embodiments illustrated and described herein, but rather determined by the following claims, interpreted according to accepted doctrines of claim interpretation, including use of the doctrine of equivalents and reversal of parts.
Two dispersers tunnels ( 20, 22 ) are provided at a disperser station. Each disperser tunnel ( 20, 22 ) houses two dispersers ( 24, 26 and 28, 30 ). Each pair of dispersers ( 24, 26 and 38, 30 ) are spaced apart and confront each other, with a mixing zone ( 42, 54 ) being defined between them. A separate conveyor ( 32, 34, 36, 38 ) is provided for feeding textile fiber modules, e.g. cotton boll modules ( 18, 18′, 18″, 18 ′″), to the dispersers ( 24, 26, 28, 30 ). Each pair of dispersers ( 24, 26 ) removes fiber clumps from the leading ends of the modules ( 18, 18′, 18″, 18 ′″) and dispenses them into the mixing zone ( 42, 54 ) in admixture with the fiber clumps from the other disperser ( 24, 26, 28, 30 ) of the pair. The blend or mixture of fiber clumps is collected in the upper run ( 50 ) of a conveyor ( 52 ) that serves to carry the fiber clumps away from the disperser station. The feed rate of the modules ( 18, 18′, 18″, 18 ′″) may be regulated and varied by regulating and varying the speed rates of the conveyors ( 32, 34, 36, 38 ). The feed conveyors may be provided with sidewalls so as to define storage bins. Bodies of particulate material may be stored in the storage bins and feed to the dispersers by use of the feed conveyors. The dispersers can be operated to dispense particles from the bodies of particulate material into the mixing zone, in admixture with particles of the other disperse of the pair. The feed rate of the conveyors can be varied for varying the feed rate of particulate material to the dispersers.
3
FIELD The present technology is directed to optical tweezers and use thereof. More specifically, the technology is directed to optical tweezers that permit real-time control. BACKGROUND An optical trap is an optical tool that utilizes the gradient forces of a focused beam of light to manipulate particles with dielectric constants higher than a surrounding media. To minimize energy, the particles move to where an electric field is the strongest. Optical trapping is used to manipulate particles, such as cells and nucleic acids. Trapped particles are typically suspended in a fluid medium. The fluid can create unwanted optical aberrations in the optical path and degrade performance. There are a number of different approaches used for creating optical traps. In one approach, a single laser beam is focused to create one optical trap. The beam remains stationary and a device used to hold the particles, such as a microscope slide, is mechanically moved. In this technique, the optical system is static and any movement is made through mechanical means such as a precise motorized stage. Only a single trap can be created with this approach. In another approach, a single laser beam is focused to create one optical trap and the trap is moved in two dimensions by means of a scanning mirror. For example, the mirror can be moved at a high speed by two actuators under computer control. A single particle can be trapped and then moved by the scanning system. Furthermore, multiple particles (typically up to 8 effectively) can be trapped by rapidly scanning the laser beam between the trapped particles. Essentially, rapidly moving the beam using the scanning mirror results in “time sharing” of one laser beam over multiple particles. Only a single trap can be created with this approach. In yet another approach, multiple laser beams are created using a spatial light modulator (SLM). The multiple beams can then be controlled by the SLM. The SLM is composed of cells, each of which can be addressed electronically from the computer. The computer can then control the refractive index of each cell which in turn controls properties of each beam. Using this approach, multiple particles can be trapped and individually controlled. However, this method is indirect and typically requires a complex and relatively slow algorithm to compute trap positions. Grier et al (U.S. Publication No. 2005/0001063) disclose a method and apparatus for laterally deflecting and separating a flow of particles using a static array of optical tweezers. While the beam can be controlled, control is not done in real-time. It is an object of the present technology to address deficiencies in the prior art and to provide other advantages. SUMMARY The present technology is a multiple beam system for optical trapping. Multiple optical traps are created that are individually controllable by a computer. The disclosed method provides direct real time control of each trap through combination of deformable mirror motion and Shack Hartmann Wave-Front Sensor (SHWFS) data. Therefore, particles can be moved at a high speed, thereby permitting analyses where real-time control is advantageous or required such as cell sorting and manipulation of micro-devices (pumps and valves). Further, the technology provides for a greater degree of beam control thereby allowing more sophisticated control of each individual trap. In one embodiment, a combination for use in optical trapping is provided, the combination comprising, in series: an adaptable reflective optical element for sculpting a laser beam to produce a sculpted beam; a beam splitter for splitting the sculpted beam into a first and a second sculpted beam; a micro lens array for dividing the first sculpted beam into an array of beamlets to produce a plurality of focal points; relay optics; and a focusing lens; and, in parallel: a wavefront curvature sensing device for accepting and analyzing the second sculpted beam and reporting to a computer. In one aspect of the embodiment, the wavefront curvature sensing device is a Shack Hartmann Wave-front Sensor. In another aspect, the adaptable reflective optical element comprises a reflective, dynamic surface and actuators. In another aspect, the adaptable reflective optical element is a deformable mirror. In another aspect, the focusing lens is an objective lens. In another aspect, the objective lens has a numerical aperture greater than unity. In another aspect, the focusing lens forms an array of high gradient optical regions. In another aspect, there are at least four actuators per optical trap. In another aspect, there are five actuators per optical trap. In another aspect, at least four actuators are configured to manipulate positions of each region of the array of high gradient optical regions. In another aspect, five actuators are configured to manipulate the positions of each region of the array of high gradient optical regions. In another aspect, the combination further comprises a second beam splitter and a real-time visual monitor. In another aspect, the real-time visual monitor is a video monitor. In another aspect, the wavefront curvature sensing device is an interferometer. In another aspect, the adaptable reflective optical element is a spatial light modulator. In a second embodiment, a method for real time optical trapping is provided. The method comprising: sculpting an incident laser beam; splitting a resulting sculpted laser beam into a first sculpted beam and a second sculpted beam; subdividing the first sculpted beam into a plurality of beamlets; transferring and focusing said beamlets to produce a plurality of focal points; concomitantly accepting and analyzing the second sculpted beam; reporting information to a controller; and moving the focal points by resculpting said incident laser beam on the basis of instructions from said controller, thereby optically trapping at least one particle in real time. In one aspect, the sculpting is effected by at least four actuators per optical trap. In another aspect, the sculpting is effected by five actuators per optical trap. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a schematic of an embodiment of a system for generating multiple moveable optical traps for manipulating small particles in accordance with the disclosed technology. FIG. 2 is an exemplary deformable mirror of the technology of FIG. 1 . FIG. 3 is an exemplary micro lens array (MLA) of the technology of FIG. 1 . FIG. 4 is a Shack Hartmann Wave-Front Sensor, which is an exemplary wavefront curvature sensing device of the technology of FIG. 1 . FIG. 5 is an objective lens, which is exemplary focusing optics of the technology of FIG. 1 . FIG. 6 is a schematic illustrating creation of optical traps by a micro lens array and movement of each trap to a new position, the new position based on a sculpted wavefront of the laser beam formed by a deformable mirror and received by the micro lens array. FIG. 7 is a schematic illustrating registration between a micro lens array used to create optical traps, a Shack Hartmann Wave-Front Sensor micro lens array, and actuators of a deformable mirror of the disclosed technology. FIG. 8 is a flowchart showing how computer software can control the system. FIG. 9 is a schematic of another embodiment of a system for generating multiple moveable optical traps for manipulating small particles in accordance with the disclosed technology. DETAILED DESCRIPTION A system for creating an optical trap, generally referred to as 10 , is shown in FIG. 1 . The system 10 includes an adaptable reflective optical element 12 such as a deformable mirror situated upstream from a beam splitter 14 , a micro lens array (MLA) 16 , relay optics 18 , and focusing optics 20 . Focusing optics 20 is typically an objective lens with a very high numerical aperture (NA), typically greater than unity. A transparent vessel 22 for containing a sample is located downstream from the focusing optics 20 in the system 10 . On a second path, a wavefront curvature sensing device 24 such as a Shack Hartmann Wave-Front Sensor (SHWFS) is located downstream from the beam splitter 14 and upstream from a computer 26 . The light source for the system 10 is a laser 28 . Any suitable laser can be used. Useful lasers include, but are not limited to, solid state lasers, diode pumped lasers, gas lasers, dye lasers, alexanderite lasers, free electron lasers, VCSEL lasers, diode lasers, Ti-Sapphire lasers, doped YAG lasers, doped YLF lasers, diode pumped YAG lasers, and flash lamp-pumped YAG lasers. Diode-pumped Nd:YAG lasers operating between 10 mW and 10 W are preferred. FIG. 2 shows a cross-sectional view of a deformable mirror 12 . The deformable mirror 12 is an exemplary adaptable reflective optical element that can be used in system 10 . The deformable mirror 12 has an array of actuators 30 positioned beneath a reflective, dynamic surface 32 and the actuators 30 are under control of a computer 26 . The computer 26 can address each actuator 30 and precisely control its length. Therefore, as the computer 26 addresses each actuator 30 , their length changes. In this manner, motions of the actuators 30 alter the shape of the reflective, dynamic surface 32 . Therefore, the entire shape of the reflective, dynamic surface 32 can be changed. An exemplary deformable mirror device is a phase only deformable mirror such as the “multi-DM” manufactured by Boston Micromachines of the USA or the “mirao” manufactured by Imagine Eyes of France. Another exemplary adaptable reflective optical element is Texas Instruments digital light processor (DLP) employing micromirrors. These dynamic optical devices have an encodable reflective surface in which a computer sculpts the wave-front surface formed therein. FIG. 3 shows an exemplary MLA 16 that can be used in system 10 . MLA 16 includes an array of micro-lenses 34 . The micro-lenses 34 of the MLA (called lenslets 34 ) typically all have the same focal length. FIG. 4 is a side perspective and a front perspective view of a SHWFS 24 . The SHWFS 24 is an exemplary wavefront curvature sensing device that can be used in system 10 . The SHWFS 24 has an array of micro-lenses 36 positioned in front of a digital imaging camera 38 . The SHWFS 24 can be used for measuring a phase profile of a wavefront such as a wavefront generated by an adaptable reflective optical element (e.g., deformable mirror 12 ). FIG. 5 is a side-view of an objective lens 20 . The objective lens 20 is an example of focusing optics that can be used in system 10 . The objective lens 20 has a back aperture 40 . With regard to FIG. 1 , operation of the system 10 using the exemplary devices shown in FIGS. 2-5 can be described as follows. A laser beam 42 is directed off a deformable mirror 12 , which is positioned in a plane conjugate to the planar surface at the back aperture 40 of the objective lens 20 (see FIG. 5 ). The laser beam 42 can be described as having a wavefront with a phase profile. The wavefront of the laser beam 42 is sculpted by the deformable mirror 12 by changing the phase profile, thereby forming a sculpted laser beam 44 that is then directed to the beam splitter 14 . The beam splitter 14 transmits a portion of the sculpted beam 44 , thereby forming a first sculpted beam, to the MLA 16 . The MLA 16 can be a static optical element that takes the incoming first sculpted laser beam and subdivides it into an array of smaller optical beams termed beamlets. FIG. 6 is an illustration of micro-lenses 34 of an MLA 16 forming beamlets 46 . The number and spacing of the beamlets 46 is dependent on the number of MLA micro-lenses 34 in the MLA 16 . Each of the beamlets 46 is brought to a focus at a focal point 48 behind or downstream of the MLA 16 . Positions of focal points 48 are determined by focal lengths of the MLA micro-lenses 34 . An adaptable reflective optical element upstream from the MLA 16 can control the positions of the focal points 48 of each beamlet 46 by adjusting the wavefront of the sculpted laser beam that is incident on the MLA 16 . For example, in system 10 , a deformable mirror 12 can be used to adjust or sculpt the wavefront of the laser beam 42 to form a sculpted wavefront 44 that is received by the MLA 16 . In this manner, the deformable mirror 12 can directly control both the motion and the positions of the focal points 48 of the MLA 16 by adapting the reflective dynamic surface 32 of the deformable mirror 12 . The sculpting by the deformable mirror 12 individually or collectively can move the focal points 48 to a desired set of new spatial positions. As shown in FIG. 6 , if a plane wave 50 with an unsculpted wavefront phase 52 is received by the MLA 16 then each beamlet 46 is brought to a focus on the axis 54 of each MLA micro lens 34 . If the wavefront phase 56 has been adjusted by a deformable mirror, (i.e., a sculpted wavefront phase 56 ) then the positions of the focal points 48 can be offset from the MLA micro lens axis 54 . The degree to which focal points 48 can be offset from the axis 54 is based on the curvature of the sculpted wavefront 56 . For example, in system 10 , the shape of a deformable mirror reflective dynamic surface 32 of deformable mirror 12 imparts a sculpted wavefront 56 onto the laser beam 42 thereby forming sculpted beam 44 . The sculpted wavefront 56 in turn dictates the positions of the beamlet focal points 48 in a plane behind the MLA, the motion of optical traps in the direction of the beam, and clockwise or counter-clockwise rotation of the traps in the plane. In system 10 , an array of focal points 48 of the MLA 16 ( FIG. 6 ) is transferred by relay optics 18 to the back aperture 40 of the objective lens 20 ( FIG. 5 ). The focal points 48 are relayed and focused into a vessel 22 by the objective lens 20 . The vessel 22 includes particles to be captured. The objective lens 20 focuses beamlets formed by the MLA 16 , such as beamlets 46 , in a high gradient optical region that is capable of trapping particles. The vessel 22 is constructed of transparent material, to allow the beamlets 46 to pass through and to reduce interference with the formation of the optical traps. In FIG. 1 , a portion of the sculpted laser beam 44 is also directed by the beam splitter 14 into a wavefront curvature sensing device 24 such as an exemplary Shack Hartmann Wave-Front Sensor (SHWFS) 24 , thereby forming a second sculpted beam. The SHWFS 24 is configured to measure the phase of the wavefront generated by the deformable mirror 12 . Wavefront phase information is then transmitted to the computer 26 where the information is utilized by control software. For fine control and manipulation of trapped particles, the SHWFS 24 can have more wavefront sample points than the number of optical traps created by the MLA 16 . As shown in FIG. 7 , the SHWFS micro-lens array 36 can be registered to the actuators 30 of the deformable mirror 12 at the corners of the SHWFS micro lens array 36 . This registration allows precise motion of the optical traps 37 and also the ability to apply specific modes to each of the beamlets 46 in the traps, such as defocus or helical modes. For clarity, only four optical traps 37 are shown in FIG. 7 , but it should be understood that a larger array of such optical traps can be created by the MLA 16 . The number of actuators 30 per optical trap 37 is related to the number of degrees of freedom of an optical trap. For example, four actuators 30 per optical trap provide control of the optical trap motion in a plane; five actuators 30 per optical trap are needed to change the optical trap depth. The number of lenses 36 in the SHWFS micro lens array 24 is directly related to the number of actuators 30 , because the registration of the actuators 30 and the SHWFS lenses 36 is preferably done such that the actuators 30 are at the corners 39 of the SHWFS lenses 36 . The number of optical traps 37 is given by the number of lenses 34 in the MLA 16 , the number of actuators 30 is given by the number of degrees of freedom of the optical traps, and the number of lenses 36 of the SHWFS 24 is given by the registration between the SHWFS 24 and the deformable mirror 12 . The number of actuators 30 is dependent on the deformable mirror 12 design and on the mirror manufacturer. For example, deformable mirrors made by Boston Micro Machines can have 140 actuators. Other deformable mirrors include 1024 actuators. The number of lenses 36 in the SHWFS micro-lens array 24 is also a function of design. If the SHWFS micro-lens array 24 has more lenses than the MLA 16 , oversampling of the wavefront shape after it leaves the deformable mirror 12 is possible. FIG. 8 is a flowchart showing how the system 10 can be controlled. To trap small particles, an operator 102 and/or the computer 26 adjust the deformable mirror 12 to direct the movement of each optical trap to acquire a selected small particle and trap it. A video camera system 66 can observe the position of the traps. The plurality of optical traps containing particles can then be configured and reconfigured. Using the video camera data, the position and identity of one or more of the trapped particles can be monitored. Control software can be employed to accept SHWFS data and to determine the shape of the reflective, dynamic surface 32 of deformable mirror 12 . The operator 102 can determine desired positions for the optical traps either manually or through a computer-based algorithm. The control software then utilizes the determined information, the SHWFS data, and current positions of the optical traps to compute shapes of the reflective, dynamic surface 32 for moving the traps to the desired positions. The foregoing are embodiments of the disclosed technology. As would be known to one skilled in the art, variations that do not alter the scope of the technology are contemplated. For example, suitable adaptable reflective optical elements having a time dependent aspect to their function include, but are not limited to, variable computer generated diffractive patterns, variable phase shifting materials, variable liquid crystal phase shifting arrays, micro-mirror arrays, piston mode micro-mirror arrays, spatial light modulators, electro-optic deflectors, acousto-optic modulators, deformable minors, reflective MEMS arrays. Through use of a dynamic phase patterning optical element, the features of a surface can be encoded to form a hologram and altered such as by a computer to effect a change in the hologram which can in turn affect the number of beamlets, the phase profile of at least one of the beamlets, and the location of at least one of the beamlets. The video camera system can be replaced with any suitable real time visual monitor. The SHWFS could be replaced with, for example, but not limited to, an interferometer or any suitable wavefront curvature sensing device. The deformable minor could be replaced with, for example, but not limited to a spatial light modulator (SLM). The particles can be contained in, for example, but not limited to, a fluid medium that is held in a small cavity created between two microscope slides. The system can further comprise a second beam splitter. FIG. 9 , for example, illustrates a system 10 ′ with a second beam splitter 92 and a real-time visual monitor 94 . Aspects of the disclosed technology, such as selective generation and control of an optical tweezer system, may be useful in a variety of commercial applications, such as, optical circuit design and manufacturing, nanocomposite material construction, fabrication of electronic components, opto-electronics, chemical and biological sensor arrays, assembly of holographic data storage matrices, rotational motor, mesoscale or nanoscale pumping, energy source or optical motor to drive a micro electrical mechanical system (MEMS), facilitation of combinatorial chemistry, promotion of colloidal self-assembly, manipulation of biological materials, interrogating biological material, concentrating selected biological material, investigating the nature of biological material, and examining biological material. In view of the many possible embodiments to which the disclosed principles may be applied, it should be recognized that the illustrated embodiments are only examples and should not be taken as limiting in scope. Rather, the scope is defined by the following claims. We therefore claim all that comes within the scope and spirit of these claims.
A combination for use in optical trapping is provided, comprising, in series: an adaptable reflective optical element for sculpting a laser beam to produce a sculpted beam; a beam splitter for splitting the sculpted beam into a first and a second sculpted beam; a micro lens array for dividing the first sculpted beam into an array of beamlets to produce a plurality of focal points; relay optics; and a focusing lens; and, in parallel: a wavefront curvature sensing device for accepting and analyzing the second sculpted beam, and reporting to a computer.
6
This is a continuation application of U.S. Ser. No. 07/743,630 filed Aug. 12, 1991, now abandoned, which is a continuation of U.S. Ser. No. 092,730 filed Sep. 3, 1987, now abandoned. BACKGROUND Certain sulfidopeptide leukotrienes have been recognized as composing the slow-reacting substance of anaphylaxis. During anaphylaxis these leukotrienes, which are potent bronchoconstrictive agents, are released by the tissues of the lung. These same leukotrienes play a role in allergic, inflammatory and other pathologic conditions. Various structurally diverse compounds such as oxarbazole, rotenone, nitrocoumarins, pyridoquinazoline carboxylic acids and imidosulfamides have been reported to possess leukotriene antagonist activity. EPO Application 85304967.4 was published on Jan. 22, 1986 which discloses similar compounds. SUMMARY The invention in its chemical compound aspect is certain novel phenyl acetylenic acetals and thioacetals which inhibit leukotriene activity. These compounds are characterized by the general structural formula I ##STR1## wherein: R 1 represents alkyl, phenyl, alkenyl, alkynyl, alkoxy, thioalkyl, alkylthio, phenylthio, phenylalkyl, phenoxyalkyl, phenoxy, thiophenoxyalkyl, or alkoxyalkyl, each of which R 1 groups may be substituted with up to three groups independently selected from --(CH 2 ) t --O--C 1-12 alkyl or --(CH 2 ) t --S--C 1-12 alkyl where t is an integer of from 0 to 6, --Y, ##STR2## where Y represents hydrogen, C 1-5 alkyl, --O--C 1-5 alkyl, halogen or --CF 3 and t is as previously defined; R 2 represents R 1 or hydrogen; X represents O or S(O) r wherein r is 0, 1 or 2; R 3 represents hydrogen or methyl; R 4 and R 5 independently represent hydrogen, hydroxyl or COOR where R is H, alkyl, alkenyl or phenyl; a and b represent 0 or 1, and at least one of a and b is 0; and m and n may be the same or different and each independently represents an integer from 0 to 5. In a preferred embodiment of the invention, R 1 represents an alkyl chain of from 4 to 12 carbon atoms, and more preferably 6 to 10 carbon atoms; R 2 preferably is --H; a and b are preferably O; R 3 is preferably --H; R 4 and R 5 are preferably the same and are --OH, or --COOR, where R is --H or alkyl, and preferably --H; X is preferably O or S; and m and n are preferably the same and represent 2, 3 or 4, most preferably 2 or 4. A more preferred embodiment is seen from structural formula I, wherein R 1 represents an alkyl chain of from 7 to 9 carbons, m and n are 2, and X represents oxygen. A second preferred embodiment is seen from structural formula I, wherein R 1 represents alkyl of from to 9 carbons, m and n are 2 and X represents S(O) r where r is zero. Preferred species falling within the scope of formula I include: 4,4'-(3-phenyl-2-propyn-1-ylidenebisoxy)bisbutanoic acid; 6,6'-(3-phenyl-2-propyn-1-ylidenebisoxy)bishexanoic acid; 4,4'-(3-phenyl-2-propyn-1-ylidenebisthio)bisbutanoic acid; 4,4'-(3-(4-hexylphenyl)-2-propyn-1-ylidenebisoxy)bisbutanoic acid; 6,6'-(3-(4-hexylphenyl)-2-propyn-1-ylidenebisoxy)bishexanoic acid; 4,4'-(3-(4-hexylphenyl)-2-propyn-1-ylidenebisthio)bisbutanoic acid; 4,4'-(3-(4-heptylphenyl)-2-propyn-1-ylidenebisoxy)bisbutanoic acid; 6,6'-(3-(4-heptylphenyl)-2-propyn-1-ylidenebisoxy)bishexanoic acid; 4,4'-(3-(4-heptylphenyl)-2-propyn-1-ylidenebisthio)bisbutanoic acid; 4,4'-(3-(4-octylphenyl)-2-propyn-1-ylidenebisoxy)bisbutanoic acid; 6,6'-(3-(4-octylphenyl)-2-propyn-1-ylidenebisoxy)bishexanoic acid; 4,4'-(3-(4-octylphenyl)-2-propyn-1-ylidenebisthio)bisbutanoic acid; 4,4'-(3-(4-nonylphenyl)-2-propyn-1-ylidenebisoxy)bisbutanoic acid; 6,6'-(3-(4-nonylphenyl)-2-propyn-1-ylidenebisoxy)bishexanoic acid; 4,4'-(3-(4-nonylphenyl)-2-propyn-1-ylidenebisthio)bisbutanoic acid; 4,4'-(3-(4-decylphenyl)-2-propyn-1-ylidenebisoxy)bisbutanoic acid; 6,6'-(3-(4-decylphenyl)-2-propyn-1-ylidenebisoxy)bishexanoic acid; 4,4 '-(3-(4-decylphenyl)-2-propyn-1-ylidenebisthio)bisbutanoic acid; 4,4 '-(3-(2-octylphenyl)-2-propyn-1-ylidenebisthio)bisbutanoic acid; 4,4 '-(3-(4-octylphenyl)-2-propyn-1-ylidenebisthio)-4,4'-bismethyl bisbutanoic acid; 4,4 '-(3-(2-(1-EZ-octenyl)phenyl)-2-propyn-1-ylidenebisoxy)bisbutanoic acid; 4,4'-(3-(2-(1-EZ -octenyl)phenyl)-2-propyn-1-ylidenebisthio)bisbutanoic acid; 4,4'-(3-(3-(1-EZ-octenyl)phenyl)-2-propyn-1-ylidenebisoxy)bisbutanoic acid; 4,4'-(3-(3-(1-EZ-octenyl)phenyl)-2-propyn-1-ylidenebisthio)bisbutanoic acid, and 4,4'-(3-(4-(1-EZ-octenyl)phenyl)-2-propyn-1-ylidenebisthio)bisbutanoic acid. The invention further encompasses the intermediates described and claimed herein. The invention further encompasses a method of treating allergy in a mammal, comprising administering to said mammal a compound of formula I in an amount effective to treat allergy. The invention further encompasses the treatment of inflammation in a mammal, comprising of administering to said mammal a compound of formula I in an amount effective to treat inflammation. The invention also encompasses the treatment of hyperproliferative skin disease in a mammal, comprising administering to said mammal a compound of formula I in an amount effective to treat hyperproliferative skin disease. The invention also encompasses a method of treating chronic obstructive lung disease in a mammal comprising administering a compound of formula I to said mammal in an amount effective to treat chronic obstructive lung disease. The invention also encompasses a method of treating arthritis in a mammal comprising administering to said mammal a compound of formula I in an amount effective to treat arthritis. When utilized herein, the terms below have the following meaning unless otherwise indicated: halogen and halo--mean fluoro, chloro, bromo and iodo; alkyl--(including the alkyl portion of phenylalkoxy, thioalkyl, alkylthio, phenylalkyl, phenoxyalkyl, thiophenoxyalkyl and alkoxyalkyl) represents straight or branched hydrocarbon chains of from 1 to 12 carbon atoms with each carbon being substitutable; phenyl--(including the phenyl portion of phenylthio, phenylalkyl, phenoxyalkyl, phenoxy and thiophenoxyalkyl) means the functional group C 6 H 5 , with each hydrogen being attached to the ring at a possible point of substitution; alkenyl--straight or branched carbon chain of from 2 to 12 carbon atoms, having at least one carbon to carbon double bond, with each hydrogen in the carbon chain being attached at a possible point of substitution. alkynyl--straight or branched hydrocarbon chain containing from 2 to 12 carbon atoms and having at least one carbon to carbon triple bond, with each hydrogen in the carbon chain occupying a possible point of substitution. methylene--means the group --CH 2 --. DETAILED DESCRIPTION The compounds of this invention are derivatives of phenyl acetylenic acetals and thioacetals. It has been discovered that these compounds possess leukotriene inhibitory activity and that changing the substituent groups in these compounds affects the leukotriene inhibitory activity in an unexpected manner. Certain compounds of the invention may exist in isomeric forms. The invention includes all such isomers, both in pure form and in admixture, including racemic mixtures. The compounds of the invention can exist in unsolvated as well as solvated forms, including hydrated forms. In general, the solvated forms, with pharmaceutically acceptable solvents such as water, ethanol and the like are equivalent to the unsolvated forms for purposes of the invention. Certain compounds of the invention are acidic in nature, e.g. those compounds which possess a carboxyl group. These compounds may form pharmaceutically acceptable salts. Examples of such salts are the sodium, potassium, aluminum, gold and silver salts. Also contemplated are salts formed with pharmaceutically acceptable amines such as ammonia, alkylamines, hydroxyalkylamines, N-methylglucamine and the like. Certain compounds of the invention form pharmaceutically acceptable salts with any of a variety of inorganic and organic bases. Suitable bases for purposes of the invention are those which form pharmaceutically-acceptable salts, such as sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, calcium hydroxide, ammonia and amines. The salt forms may be converted back to their respective acid forms by treatment with an acid such as dilute hydrochloric acid. The acid forms and their respective salts differ in certain physical properties such as solubility, but they are otherwise equivalent for purposes of the invention. All such salts are intended to be pharmaceutically acceptable salts within the scope of the invention, and are considered equivalent to the free forms of the corresponding compounds for purposes of the invention. The compounds of formula I may generally be produced from substituted benzaldehydes as further described below. To synthesize the diethylacetal starting compound, substituted benzaldehyde may be converted to the dihalogenated methylene compound by standard methods. One such standard method is to react the substituted benzaldehyde in the presence of dibromomethylenetriphenylphosphorane to yield the 1-substituted phenyl-2,2-dibromoethene compound. The 1-substituted phenyl-2,2-dibromoethene may thereafter be treated with butyl lithium to yield a terminal substituted phenyl acetylene compound. Finally, the terminal substituted phenyl acetylene compound may react with triethoxymethane in the presence of a catalyst, such as zinc iodide, to yield the substituted phenyl acetylene diethylacetal. The substituted phenylacetylene diacetal compound may serve as the starting material for the preparation of the final acetals and thioacetals. For example, the substituted phenylacetylene diacetal may undergo transacetalization with either 1,4-butanediol monobenzoate or 1,6-hexanediol monobenzoate to yield substituted phenyl propynylidene bisoxy compounds. The substituted phenyl propynylidene bisoxy compounds may be saponified to the bis hydroxyacetals in the presence of base, which hydroxyacetals may be subsequently oxidized according to the novel processes described herein. Alternatively, the diethylacetal may be transthioacetalized, with 4-mercapto-n-butanoic acid in the presence of boron trifluoride etherate to yield the target compounds. The compounds which are the subject of this invention show activity and are useful for the treatment of allergies, the preferred anti-allergy use being the treatment of chronic obstructive lung disease. Chronic obstructive lung disease as used herein means disease conditions in which the passage of air into and out of the lungs is obstructed or diminished, such as in bronchitis, asthma and the like. The anti-allergy method of this invention is shown by tests which measure a compound's inhibition of contractile responses of strips of lung parenchyma. Male Hartley guinea pigs (600-800 g body weight) were killed by a blow to the head and then exsanguinated. The lungs were inflated with 5 ml. of air through the trachea, the chest cavity opened, and the lungs perfused in situ through the pulmonary artery with Tyrode's solution. The lower lobe of each lung was excised and dissected into four strips (3×10 mm), each of which was suspended in a constant temperature (37° C.) organ bath containing 10 mL of Tyrode's solution and aerated with 95% O 2 -5% CO 2 . Each lung strip was attached to a Harvard isometric muscle transducer and tension was recorded with a Harvard recording module. The initial tension was adjusted to 2 g and the tissues allowed to equilibrate until a steady baseline was reached. Test compounds (prepared as 200-fold stock solutions in dimethyl sulfoxide (DMSO) or vehicle (0.5% DMSO final concentration) were added to the lung strips 5 min. before the tissues were challenged with final concentrations of 1×10 -8 M LTC 4 . Lung strips prepared from animals sensitized to ovalbumin were challenged with 0.75)g/mL of ovalbumin. Each lung strip received only a single addition of test compound followed by a single agonist challenge. The peak contractile response to LTC 4 was recorded and expressed as a percent of the maximum response (obtained with 1×10 -4 M histamine) of that lung strip. The effect of each test compound is expressed as percent inhibition of the contractile response calculated as follows: ##EQU1## The activity of selected compounds of this invention is set forth in Table I. TABLE I______________________________________INHIBITION OF LTC.sub.4 -INDUCED CONTRACTIONS OFGUINEA PIG LUNG PARENCHYMA BY ACETALSAND THIOACETALS.sup.a ##STR3##R = H, where X = S, r = O Substituents % InhibitionR.sup.1 (position) X m n R.sup.3 50)M 10)M______________________________________H O 2 2 H 1 --.sup.bH O 4 4 H 15 --.sup.bH S 2 2 H 4 --.sup.bC.sub.6 H.sub.13 (para) O 2 2 H 58.sup.c 5C.sub.6 H.sub.13 (para) O 4 4 H 81.sup.c 25C.sub.6 H.sub.13 (para) S 2 2 H 87.sup.c 43.sup.cC.sub.7 H.sub.15 (para) O 2 2 H 70.sup.c 7C.sub.7 H.sub.15 (para) O 4 4 H 62.sup.c 37.sup.cC.sub.7 H.sub.15 (para) S 2 2 H 83.sup.c 65.sup.cC.sub.8 H.sub.17 (para) O 2 2 H 72.sup.c 67.sup.cC.sub.8 H.sub.17 (para) O 4 4 H 67.sup.c 24C.sub.8 H.sub.17 (para) S 2 2 H 68.sup.c 71.sup.cC.sub.9 H.sub.19 (para) O 2 2 H 77.sup.c 66.sup.cC.sub.9 H.sub.19 (para) O 4 4 H 76.sup.c 19C.sub.9 H.sub.19 (para) S 2 2 H 100.sup.c 76.sup.cC.sub.10 H.sub.21 (para) O 2 2 H 26 --.sup.bC.sub.10 H.sub.21 (para) O 4 4 H 9 --.sup.bC.sub.10 H.sub.21 (para) S 2 2 H 22 --.sup.bC.sub.8 H.sub.17 (ortho) S 2 2 H 86 38C.sub.8 H.sub.17 (para) S 2 2 --CH.sub.3 66 241-(EZ)- S 2 2 H 73 43C.sub.8 H.sub.15 (ortho)1-(EZ)- S 2 2 H 100 75C.sub.8 H.sub.15 (meta)1-(EZ)- O 2 2 H 59 0C.sub.8 H.sub.15 (ortho)1-(EZ)- O 2 2 H 72 13C.sub.8 H.sub.15 (meta)1-(EZ)- S 2 2 H --.sup.b --.sup.bC.sub.8 H.sub.15 (para)______________________________________ .sup.a Percent inhibition by FPL 55712 (standard) at 10)M = 99. .sup.b Not tested. .sup.c Statistically significant (p = 0.05) using Student's ttest. When a compound of the invention is used for the treatment of allergy, it can be used by any conventional route of administration, e.g., orally, parenterally, inhalation, topically, etc. in single or multiple daily doses. When used orally or parenterally, the compound can be administered in an amount ranging from about 0.01 mg/kg to abut 100 mg/kg and preferably about 0.1 mg/kg to about 10 mg/kg. When used topically or by inhalation, the dose can be varied to deliver from about 0.01 to about 100 mg per dose, preferably from about 0.1 to about 10 mg per dose. Other modes of administration can be used to deliver from about 0.001 mg to about 1000 mg per dose, preferably from about 0.1 mg to about 10 mg per dose. The anti-inflammatory activity and the anti-hyperproliferative skin disease effects of the compounds are demonstrated by measuring 5-lipoxygenase inhibitory activity. The enzyme 5-lipoxygenase plays a role in the inflammatory process and in the hyperproliferation of skin cells. Inhibition of 5-lipoxygenase by compounds of the invention is therefore predictive of anti-inflammatory activity and hyperproliferative skin disease suppression. As used herein, the term "hyperproliferative skin disease" means any condition a symptom of which is accelerated skin cell production, flaking, scales or papular lesions, including, for example, psoriasis, eczema, dandruff and the like. The effect of the compounds of the invention on 5-lipoxygenase activity is determined using rat neutrophils. Male Wistar-Lewis rats are injected intravenously with 5 mg BSA in 0.2 ml pyrogen free saline followed by an intrapleural injection of 500 ug of the IgG fraction of rabbit anti-BSA (Cappel Labs., Lot 17782) in 0.2 ml pyrogen free saline. Injections are made under light ether anesthesia. Four hours later, the pleural cavity exudate consisting of 85 to 95% neutrophils is removed. Neutrophils are isolated from the pleural exudates by centrifugation of 4° C. for 10 rain at 200×g. The cell pellet is resuspended in 17 mM Tris HCl buffer, pH 7.2, containing 0.75% NH 4 Cl to lyse contaminating erythrocytes followed by centrifugation at 4° C. for 5 min at 200×g. The pelleted neutrophils are rewashed in 50 mM Tris HCl, pH 7.4, containing 100 mM NaCl, followed by the same centrifugation. The cell pellet is resuspended in 50 mM Tris HCl, pH 7.4, containing 100 mM NaCl and 1 mM CaCl 2 , at 3-12×10 7 intact neutrophils per ml. Solutions of compounds in methanol are dried, then resuspended in the cell suspension for 4 min. Arachidonic acid metabolism is determined by incubating 0.1 ml of this suspension with 40 uM [1- 14 C] arachidonic acid (AA) (Amersham, 59 Ci/mole), in the presence of 0.1% BRIJ 56 and 10 uM of ionophore A23187. Arachidonic acid metabolism as well as the various drug and reagent abbreviations are described in detail in Arch. Dermatol, Vol. 119, pages 541 to 547 (July, 1983), the teachings of which are incorporated herein by reference. Assays run in triplicate are initiated by adding cells with inhibitor to a film of the BRIJ 56, arachidonic acid and A23187 at 37° C. After one minute, reactions are terminated by the addition of 2.4 ml of a chloroform: methanol (1:1 v/v) mixture and 0.9 ml of 0.1% formic acid. The suspension is vortexed, immediately cooled on ice, centrifuged, and the organic layer withdrawn. The extract is evaporated under a stream of N 2 and resuspended in 0.1 ml chloroform:methanol (2:1 v/v) for spotting on thin layer plates (Sil G-25, without gypsum, Brinkmann). Chromatograms are developed with ether:methanol (80:20) for 2 cm, dried, and redeveloped with ligroine:diethylether:glacial acetic acid (40:60:1 v/v/v) for an additional 20 cm. Products, leukotriene B 4 (LTB 4 ), 12-hydroxy-heptadecatrienoic acid (HHT) and 5-hydroxy eicosatetraenoic acid (5-HETE), are located by autoradiography and appropriate regions of the thin layer plates are scraped and counted in a liquid scintillation counter. Metabolites are identified by co-chromatography with authentic standards. Based upon the analysis of the compounds described above, the compounds of the invention exhibit anti-inflammatory activity when used in an amount effective to treat inflammation, and also exhibit anti-hyperproliferative skin disease activity when used in an amount effective to treat hyperproliferative skin disease. When administered for the anti-inflammatory effects, the compounds can be administered in any therapeutically useful method, such as orally, topically or parenterally, in single or divided daily doses. When used orally for the treatment of inflammation, the compounds can be administered in an amount ranging from about 0.01 mg/kg to about 100 mg/kg, preferably from 0.1 mg/kg to about 10 mg/kg per day. When administered parenterally for inflammation the compounds can be administered in an amount ranging from about 0.01 mg/kg to about 100 mg/kg, preferably from about 0.1 mg/kg to about 10 mg/kg. When used topically for the treatment of inflammation, the compounds can be administered in any appropriate pharmaceutical dosage form, e.g., cream, ointment, lotion, transdermal patch, etc. in a concentration ranging from about 0,001 to about 10 percent, and preferably about 0.01 to about 1 percent. When administered by other conventional routes, e.g. intranasally by aerosol, rectally by suppository or cream, etc., the dosage will similarly range from about 0.01 mg/kg to about 100 mg/kg, preferably from about 0.1 to about 10 mg/kg. When administered for the treatment of hyperproliferative skin disease, the compounds can be administered in any therapeutically useful method, such as orally, parenterally, topically, etc., and the preferred method of administration is topical. When administered orally or parenterally for the treatment of hyperproliferative skin disease, the compounds may be administered in an amount ranging from about 0.01 mg/kg to about 100 mg/kg, and preferably from about 0.1 mg/kg to about 10 mg/kg. When administered topically, the compounds of the invention can be administered in any pharmaceutically acceptable dosage form, such as a cream, ointment, lotion, solution, transdermal patch, etc., in an amount ranging from about 0.001 mg to about 100 mg per dose, preferably from about 0.01 to about 10 mg per dose. For preparing pharmaceutical compositions from the compounds described herein, the compounds may be mixed with inert, pharmaceutically acceptable carriers which can be either solid or liquid. Solid form preparations include but are not limited to powders, tablets, dispersible granules, capsules, cachets and suppositories. A solid carrier can be one or more substances which may also act as diluents, flavoring agents, solubilizers, lubricants, suspending agents, binders or tablet disintegrating agents; it can also be an encapsulating material. In powders, the carrier is a finely divided solid which is in admixture with the finely divided active compound. In the tablet the active compound is mixed with carrier having the necessary binding properties in suitable proportions and compacted in the shape and size desired. The active ingredient contained in the powders or tablets preferably ranges from about 5 to about 70 percent of the tablet or powder weight. Suitable solid carriers are magnesium carbonate, magnesium stearate, talc, sugar, lactose, pectin, dextrin, starch, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose, a low melting point wax, cocoa butter and the like. The term "preparation" is intended to include the formulation of the active compound with encapsulating material as carrier providing a capsule in which the active component (with or without other carriers) is surrounded by carrier, which is thus in association with it. Similarly, cachets are included. Tablets, powders, cachets and capsules can be used as solid dosage forms suitable for oral administration. For preparing suppositories, a low melting pointing wax such as a mixture of fatty acid glycerides or cocoa butter is first melted, and the active ingredient is dispersed homogeneously therein as by stirring. The molten homogeneous mixture is then poured into convenient sized molds, allowed to cool and thereby solidify. Liquid form preparations include solutions, suspensions and emulsions. As an example may be mentioned water or water-propylene glycol solutions for parental injection. Liquid preparations can also be formulated in solution in aqueous polyethylene glycol solution. Aqueous solutions suitable for oral use can be prepared by adding the active component in water and adding suitable colorants, flavors, stabilizing, sweetening, solubilizing and thickening agents as desired. Aqueous suspensions suitable for oral use can be made by dispersing the finely divided active component in water with viscous material, i.e., natural or synthetic gums, resins, methylcellulose, sodium carboxymethylcellulose and other well-known suspending agents. Also included are solid form preparations which are intended to be converted, shortly before use, to liquid form preparations for either oral or parenteral administration. Such liquid forms include solutions, suspensions and emulsions. These particular solid form preparations are most conveniently provided in unit dose form and as such are used to provide a single liquid dosage unit. Alternately, sufficient solid may be provided so that after conversion to liquid form, multiple individual liquid doses may be obtained by measuring predetermined volumes of the liquid form preparation as with a syringe, teaspoon or other volumetric container. When multiple liquid doses are so prepared, it is preferred to maintain the unused portion of said liquid doses at low temperature (i.e., under refrigeration) in order to retard possible decomposition. The solid form preparations intended to be converted to liquid form may contain, in addition to the active material, flavorants, colorants, stabilizers, buffers, artificial and natural sweeteners, dispersants, thickeners, solubilizing agents and the like. The solvent utilized for preparing the liquid form preparation may be water, isotonic water, ethanol, glycerine, propylene glycol and the like as well as mixtures thereof. Naturally, the solvent utilized will be chosen with regard to the route of administration, for example, liquid preparations containing large amounts of ethanol are not suitable for parenteral use. Preferably, the pharmaceutical preparation is in unit dosage form. In such form, the preparation is subdivided into unit doses containing appropriate quantities of the active component. The unit dosage form can be a packaged preparation, the package containing discrete quantities of preparation, for example, packeted tablets, capsules and powders in vials or ampoules. The unit dosage form can also be a capsule, cachet or tablet itself or it can be the appropriate number of any of these in packaged form. Formulations for topical application, e.g., for use in treating hyperproliferative skin diseases, may include the above liquid forms, creams, aerosols, sprays, dusts, powders, lotions and ointments which are prepared by combining an active ingredient according to this invention with conventional pharmaceutical diluents and carriers commonly used in topical dry, liquid, cream and aerosol formulations. Ointment and creams may, for example, be formulated with an aqueous or oil base with the addition of suitable thickening and/or gelling agents. Such bases may, thus, for example, include water and/or an oil such as liquid paraffin or a vegetable oil such as peanut oil or castor oil. Thickening agents which may be used according to the nature of the base include soft paraffin, aluminum stearate, cetostearyl alcohol, propylene glycol, polyethylene glycols, woolfat, hydrogenated lanolin, beeswax, etc. Lotions may be formulations with an aqueous or oil base and will, in general, also include one or more of the following, namely, stabilizing agents, emulsifying agents, dispersing agents, suspending agents, thickening agents, coloring agents, perfumes and the like. Powders may be formed with the aid of any suitable powder base, e.g., talc, lactose, starch, etc. Drops may be formulated with an aqueous base or non-aqueous base also comprising one or more dispersing agents, suspending agents, solubilizing agents, etc. The topical pharmaceutical compositions according to the invention may also include one or more preservatives or bacteriostatic agents, e.g., methyl hydroxybenzoate, propyl hydroxybenzoate, chlorocresol, benzalkonium chlorides, etc. The topical pharmaceutical compositions according to the invention may also contain other active ingredients such as antimicrobial agents, particularly antibiotics, anesthetics, analgesics and antipruritic agents. The quantity of active compound in a unit dose of preparation may be varied or adjusted from about 0.1 mg to about 100 mg according to the particular application and the potency of the active ingredient. The compositions can, if desired, also contain other therapeutic agents. Each of the dosages described herein may be varied depending upon the requirements of the patient, the severity of the condition being treated and the particular compound being employed. Determination of the proper dosage for a particular situation is within the skill of the art. Generally, treatment is initiated with smaller dosages which are less than the optimum dose of the compound. Thereafter, the dosage is increased by small increments until the optimum effect under the circumstances is reached. For convenience, the total daily dosage may be divided and administered in portions during the day if desired. This invention is further exemplified by the following non-limiting Preparative Examples and Examples. Aldehydes prepared as in Example 1 are treated in accordance with the following general reaction scheme. ##STR4## PREPARATIVE EXAMPLE 1 2-and 4-(n-Alkyl)-Benzaldehydes A. Rosenmund Reduction--Hydrogenate a mixture of 4-(n-decyl)benzoyl chloride (28 g., 0.1 mol), 10% palladium on carbon (2 g.), 2,6-lutidine (10.9 g., dried over KOH and distilled), and tetrahydrofuran (THF) (300 ml., distilled from LiAlH 4 ) in a Paar apparatus for 30 min. at 25° C. under an H 2 atmosphere (62 psi). Filter the resulting mixture and collect the catalyst. Wash the catalyst with THF. Evaporate the filtrate and partition the residue between diethyl ether and H 2 O. Wash the combined organic solutions with aqueous HCl (0.1N) and NaHCO 3 (0.1N) solutions. Evaporate the solvent from the dried organic solution to give a liquid. Distill the liquid to give 4-(n-decyl)benzaldehyde (19 g. 77% yield, b.p. 152°-156° C. at 0.3 mm). By substituting 4-(n-heptyl) benzoyl chloride for the starting compound 4-(n-decyl)benzoyl chloride, and following the process of part A above, 4-(n-heptyl)benzaldehyde may be produced. (83% yield, b.p. 120°-129° C. at 0.6 mm). B. Oxidative Formylation--Allow a two-phase mixture of trifluoroacetic acid (150 mL) and hexamethylene tetramine (14.0 g, 0.100 mol), and 1-phenyl-n-nonane (20.4 g, 0.100 mol) to stand 18 hrs. at 25° C., and then reflux for 22 hrs. Concentrate the homogenous reaction mixture and pour the residue over ice and H 2 O (total of 600 mL). Add diethyl ether (200 mL) and stir the mixture vigorously for 30 min. Raise the pH of the mixture to pH 8 with solid Na 2 CO 3 , and add diethyl ether (200 mL). Shake the layers and separate. Extract the aqueous phase with diethyl ether. Wash the combined organic solutions with H 2 O and brine, dry and filter. Evaporate the solvent, and distill the residue to give 4-(n-nonyl)benzaldehyde (57% yield, 13.2 g) b.p. 136°-139° C. at 0.55 mm. C. Alkylation 2-(n-Octyl)benzaldehyde is prepared from 2-methyl benzaldehyde according to Harris and Roth [T. P. Harris and G. P. Roth, J. Org. Chem. 44, 2004 (1979)]. (b.p. 104°-106° C. at 0.4 mm). Alternatively, transthioacetalization of compound V will lead directly to certain compounds I as disclosed below. PREPARATIVE EXAMPLE 2 Preparation of Disubstituted Styrenes (III) Wittig olefination according to Corey and Fuchs (Corey, E. J.; Fuchs, P. L.; Tet. Let. 1972, 3769-3772) the teachings of which are incorporated herein by reference gives the disubstituted styrene compounds described below. Treat the 2- or 4-(n-alkyl)benzaldehyde designated below with triphenylphosphine and CBr 4 in CH 2 Cl 2 to yield the 2- or 4-(n-alkyl)-2,2-dibromostyrene shown in Table II below. Alternatively, treat the 2-or 4-(n-alkyl)benzaldehyde in the presence of zinc dust with triphenylphosphine and CBr 4 in CH 2 Cl 2 . TABLE II______________________________________2- or 4-(N-ALKYL)-2,2-DIBROMOETHENYL)BENZENES(n-alkyl)-benzaldehyde Physical(n-alkyl)substituent Product Yield State______________________________________4-(n-hexyl) (2,2-dibromoethenyl)-4- 85% Liquid ( -n-hexyl)-benzene.4-(n-heptyl) (2,2-dibromoethenyl)-4- 89% Liquid ( -n-heptyl)benzene.4-(n-octyl) (2,2-dibromoethenyl)-4- -- Liquid ( -n-octyl)benzene.4-(n-nonyl) (2,2-dibromoethenyl)-4- -- Liquid ( -n-nonyl)benzene.4-(n-decyl) (2,2-dibromoethenyl)-4- 98% Liquid ( -n-decyl)benzene.2-(n-octyl) (2,2-dibromoethenyl)-2- 81% Liquid.sup.a ( -n-octyl)benzene.______________________________________ .sup.a Purified by chromatography over silica gel and elution with pet. ether. Some crude (2,2-dibromoethenyl)benzenes require chromatographic separation from the corresponding 4-(n-alkyl)-benzaldehydes. Chromatography over silica gel (50 g/g) and elution with pet. ether effects purification as evidenced by TLC and 1 H-NMR. Chromatographed or crude samples are suitable for use in Preparative Example 3. PREPARATIVE EXAMPLE 3A Preparation of 2-or 4-(n-Alkyl)Phenylacetylenes (IV) These compounds are made according to Corey and Fuchs, supra, as further described below. React the title compound of Preparative Example 2, 2- or 4-(n-alkyl)-(2,2-dibromoethenyl)-benzene with n-butyllithium in THF (-78° C. for 1 hour, then 25° C. for 1 hour) to form the 2- or 4-(n-alkyl)-phenyllithium acetylide. Hydrolyze the 2- or 4-(n-alkyl)-phenyllithium acetylide to yield the title compound, 2- or 4-(n-alkyl)phenylacetylene as shown in Table III below. TABLE III______________________________________2- OR 4-(N-ALKYL)PHENYLACETYLENES (IV)(2,2-dibromoethenyl)-2 or 4-(n-alkyl)benzene______________________________________4-(n-alkyl)-group Product Yield Boiling point (°C.)______________________________________hexyl 4-( -n-hexyl)phenyl- 72% 82-84° at 0.05 m acetyleneheptyl 4-( -n-heptyl)phenyl- 64% 70-90° at 0.08 mm acetyleneoctyl 4-( -n-octyl)phenyl- 64% 101-105° at 0.7 mm acetylenenonyl 4-( -n-nonyl)phenyl- 48% 118-120° at 0.05 mm acetylenedecyl 4-( -n-decyl)phenyl- 50% 126-127° at 0.1 mm acetylene2-(n-alkyl)-group Resultant Compound Yield Boiling point______________________________________octyl 2-( -n-octyl)phenyl- 62% 97° at 0.7 mm acetylene______________________________________ PREPARATIVE EXAMPLE 3B Preparation of Octenylphenylacetylene Compounds ##STR5## o, m, or p-bromobenzaldehyde is treated as disclosed in J. Org. Chem. Vol. 46, 2280 (1981) to yield o, m, or p-acetylenic benzaldehyde, which is then treated as described in Bull. Chem. Soc. Japan, 2840 (1976) to yield the o, m or p- octenyl-1-phenylacetylene compounds. PREPARATIVE EXAMPLE 4 Preparation of Bisoxy Bisethanes (V) The bisoxy bisethanes of this Preparative Example are made according to Howk and Sauer the teachings of which are incorporated herein by reference (Howk, B. W.; Sauer, J. C.; J. Am. Chem. Soc. 1958, 80, 4607-4609; Howk, B. W.; Sauer, J. C.; Org. Syn. 1963, Coll. Vol. IV, 801-803) as further described below. Heat the title compound of Preparative Example 3 (0.5 mole) with triethyl orthoformate (0.5 mole) in the presence of ZnCl 2 at atmospheric pressure for 2.0 hours. Distill off ethanol as it is formed until cessation to yield the resultant title compound, shown in Table IV below. Some products require purification by chromatography over silica gel (60-100 g/g) and elution with pet. ether. Combine the fractions of the diethylacetals to maximize purity, not yield, as measured by TLC and 1 H-NMR. Chromatographed or crude samples of the bisoxy bisethanes are used directly in Preparative Example 5. Representative examples of bisoxy bisethanes are disclosed below in Table IV. Each resultant compound is in the form of a liquid. TABLE IV______________________________________BISOXY BISETHANES (V)2-,3- or 4- (n-alkyl or n-alkenyl)phenylacetylene Resultant Compound Yield______________________________________4-( -n-hexyl) (3,3-diethoxy-1-propynyl)- 93% 4-( -n-hexyl)benzene4-( -n-heptyl) (3,3-diethoxy-1-propynyl)- 83% 4-( -n-heptyl)benzene4-( -n-octyl) (3,3-diethoxy-1-propynyl)- 85% 4-( -n-octyl)benzene4-( -n-nonyl) (3,3-diethoxy-1-propynyl)- 95% 4-(n-nonyl)benzene4-( -n-decyl) (3,3-diethoxy-1-propynyl)- 73% 4-( -n-decyl)benzene2-( -n-octyl) (3,3-diethoxy-1-propynyl)- 78%.sup.a 2-( -n-octyl)benzene2-(1-EZ-octenyl) (3,3-diethoxy-1-propynyl)- --.sup.b 2-(1-EZ-octenyl)benzene3-(1-EZ-octenyl) (3,3-diethoxy-1-propynyl)- --.sup.b 3-(1-EZ-octenyl)benzene4-(1-EZ-octenyl) (3,3-diethoxy-1-propynyl)- --.sup.b 4-(1-EZ-octenyl)benzene______________________________________ .sup.a Purified by silica gel chromatography and eluted with chloroform:pet. ether (1:3). .sup.b In the form of an oil PREPARATIVE EXAMPLE 5A 4,4'-[(3-Phenyl or 3-(4-(Alkylphenyl))2-Propyn-1-Ylidenebis(oxy))]Bis(Butanol) Dibenzoate Compounds (Acetalesters VI) Combine a diethoxy compound prepared as in Preparative Example 4, (designated in Column 1 of Table V below), (10-50 mmol., 0.08-0.50M initially), with 4-benzoyloxy-1-butanol (0.16-1.0M, 2-3 mmol/mmol of bisoxy bisethane) and p-toluene sulfonic acid (3-6 mmol). Distill off benzene at atmospheric pressure and add additional benzene as needed over 1.5-4.5 hours. Cool the solution, and wash sequentially with aqueous NaHCO 3 , water and brine. Dry the solution, filter and concentrate to yield the title compound listed in Table V below. TABLE V______________________________________4,4'-[3-PHENYL OR 3-(4-ALKYL OR 4-ALKENYL PHENYL)-2-PROPYN-1-YLIDENEBIS(OXY)]BIS[BUTANOL]DIBENZOATE COMPOUNDS (VI)Diethylacetal Title Compound______________________________________(3,3-diethoxy-1-propynyl) 4,4'-[3-phenyl-2-propyn-1-ylidenebisbenzene (oxy)]bis(butanol) dibenzoate(3,3-diethoxy-1-propynyl)- 4,4'-[3-(4-hexylphenyl)-2-propyn-1-4-( -n-hexyl)benzene ylidenebis(oxy)]bis(butanol) dibenzoate(3,3-diethoxy-1-propynyl)- 4,4'-[3-(4-heptylphenyl)-2-propyn-1-4-( -n-heptyl)benzene ylidenebis(oxy)]bis(butanol) dibenzoate(3,3-diethoxy-1-propynyl)- 4,4'-[3-(4-octylphenyl)-2-propyn-1-4-4-( -n-octyl)benzene ylidenebis(oxy)]bis(butanol) dibenzoate(3,3-diethoxy-1-propynyl)- 4,4'-[3-(4-nonylphenyl)-2-propyn-1-4-( -n-nonyl)benzene ylidenebis(oxy)]bis(butanol) dibenzoate(3,3-diethoxy-1-propynyl)- 4,4'-[3-(4-decylphenyl)-2-propyn-1-4-( -n-decyl)benzene ylidenebis(oxy)]bis(butanol) dibenzoate(3,3-diethoxy-2-propynyl)- 4,4'-[3-(2-(1-EZ octenyl)phenyl)-2-2-(1-EZ-octenyl)benzene propyn-1-ylidenebis(oxy)]bis(butanol) dibenzoate.sup.b(3,3-diethoxy-2-propynyl)- 4,4'-[3-(3-(1-EZ octenyl)phenyl)-2-3-(1-EZ-octenyl)benzene propyn-1-ylidenebis(oxy)]bis(butanol) dibenzoate______________________________________ PREPARATIVE EXAMPLE 5B Preparation of 6,6'-(3-Phenyl or 3-(4-Alkylphenyl))-2-Propyn-1-Ylidenebisoxy)Bis[Hexanol]Dibenzoate Compounds (VI) Combine a diethoxy compound prepared as in Preparative Example 4 (designated in Table VI below), (10-16 mmol, 0.06-0.36M initially), with 6-benzoyloxy-1-hexanol (0.26-1.0M initially, 2-4 mmol/mmol bisoxy hisethane) and para-toluene sulfonic acid (2-4 mmol). Distill off benzene and add additional benzene as needed over 1.5 to 4.5 hours. Concentrate to yield a residue which is a compound listed in Table VI below. TABLE VI______________________________________6,6'-[3-PHENYL AND 3-(4-ALKYLPHENYL)-2-PROPYN-1-YLIDENEBIS(OXY)]BIS(HEXANOL) DIBENZOATECOMPOUNDS (VI)Diethylacetal Title Compound______________________________________(3,3-diethoxy-1-propynyl) 6,6'-[3-phenyl-2-propyn-1-benzene ylidenebis(oxy)]bis(hexanol) dibenzoate1-(3,3-diethoxy-1-propynyl)- 6,6'-[3-(4-hexylphenyl)-2-propyn-1-4-( -n-hexyl)benzene ylidenebis(oxy)]bis(hexanol) dibenzoate1-(3,3-diethoxy-1-propynyl)- 6,6'-[3-(4-heptylphenyl)-2-propyn-1-4-( -n-heptyl)benzene ylidenebis(oxy)]bis(hexanol) dibenzoate1-(3,3-diethoxy-1-propynyl)- 6,6'-[3-(4-octylphenyl)-2-propyn-1-4-( -n-octyl)benzene ylidenebis(oxy)]bis(hexanol) dibenzoate1-(3,3-diethoxy-1-propynyl)- 6,6'-[3-(4-nonylphenyl)-2-propyn-1-4-( -n-nonyl)benzene ylidenebis(oxy)]bis(hexanol) dibenzoate1-(3,3-diethoxy-1-propynyl)- 6,6'-[3-(4-decylphenyl)-2-propyn-1-4-( -n-decyl)benzene ylidenebis(oxy)]bis(hexanol) dibenzoate.sup.a______________________________________ .sup.a Residue is chromatographed over silica gel (70/g) and chloroform:pet. ether (85:15). PREPARATIVE EXAMPLE 6 Preparation of Hydroxyacetal Compounds (VII) Saponify a dibenzoate compound of Preparative Examples 5A and 5B listed in Table VII (0.055-0.105M initially) to a bishydroxy acetal by adding excess KOH (8-22 mmol/mmol of E, 0.59-1.6M initially) and refluxing in ethanol and H 2 O (70/30 v/v) for 1.5-4 hours. Evaporate the ethanol from the cooled reaction mixture and dilute the residue with H 2 O, and extract with diethyl ether. Combine extracts and wash with H 2 O and brine, dry and filter. Chromatograph the residue over silica gel (70-130 g/g) with CHCl 3 :methanol:acetic acid (95-98.5:4.5-1.35:0.5-0.15) to purify. Combine the fractions to maximize purity, not yield, and evaporate the solvents to yield the title compound shown in Table VII below. Dry the samples in vacuo, and test for purity. (TLC, 1 H-NMR). Each of the compounds made by the process described herein is in the form of an oil. TABLE VII______________________________________HYDROXYACETALS (VII)Acetalesters Title Compound______________________________________4,4'-[3-phenyl-2-propyn-1- 4,4'-[3-phenyl-2-propyn-1-ylidenebisoxy)]bis ylidenebis(oxy)]bis(butanol).sup.a(butanol) dibenzoate6,6'-[3-phenyl-2-propyn-1- 6,6'-[3-phenyl-2-propyn-1-ylidenebis(oxy)]bis ylidenebis(oxy)]bis(hexanol)(hexanol) dibenzoate4,4'-[3-(4-hexylphenyl)-2- 4,4'-[3-(4-hexylphenyl)-2-propyn-1-propyn-1-ylidenebis(oxy)]bis ylidenebis(oxy)]bis(butanol)(butanol) dibenzoate6,6'-[3-(4-hexylphenyl)- 6,6'-[3-(4-hexylphenyl)-2-propyn-1-2-propyn-1-ylidenebis(oxy)]bis ylidenebis(oxy)]bis(hexanol)(hexanol) dibenzoate4,4'-[3-(4-heptylphenyl)-2- 4,4'-[3-(4-heptylphenyl)-2-propyn-1-propyn-1-ylidenebis(oxy)]bis ylidenebis(oxy)]bis(butanol)(butanol) dibenzoate6,6'-[3-(4-heptylphenyl)-2- 6,6'-[3-(4-heptylphenyl)-2-propyn-1-propyn-1-ylidenebis(oxy)]bis ylidenebis(oxy)]bis(hexanol)(hexanol) dibenzoate4,4'-[3-(4-octylphenyl)-2- 4,4'-[3-(4-octylphenyl)-2-propyn-1-propyn-1-ylidenebis(oxy)]bis ylidenebis(oxy)]bis(butanol).sup.b(butanol) dibenzoate6,6'-[3-(4-octylphenyl)-2- 6,6'-[3-(4-octylphenyl)-2-propyn-1-propyn-1-ylidenebis(oxy)]bis ylidenebis(oxy)]bis(hexanol)(hexanol) dibenzoate4,4'-[3-(4-nonylphenyl)-2- 4,4'-[3-(4-nonylphenyl)-2-propyn-1-propyn-1-ylidenebis(oxy)]bis ylidenebis(oxy)]bis(butanol)(butanol) dibenzoate6,6'-[3-(4-nonylphenyl)-2- 6,6'-[3-(4-nonylphenyl)-2-propyn-1-propyn-1-ylidenebis(oxy)]bis ylidenebis(oxy)]bis(hexanol)(hexanol) dibenzoate4,4'-[3-(4-decylphenyl)-2- 4,4'-[3-(4-decylphenyl)-2-propyn-1-propyn-1-ylidenebis(oxy)]bis ylidenebis(oxy)]bis(butanol)(butanol) dibenzoate6,6'-[3-(4-decylphenyl)-2- 6,6'-[3-(4-decylphenyl)-2-propyn-1-propyn-1-ylidenebis(oxy)] bis ylidenebis(oxy)]bis(hexanol)(hexanol) dibenzoate4,4'-[3-(2-(1-EZ-octenyl)phenyl)- 4,4'-[3-(2-(1-EZ-octenyl)phenyl)-2-2-propyn-1-ylidenebis(oxy)]bis proypn-1-ylidenebis(oxy)](butanol) dibenzoate bis(butanol.sup.c4,4'-[3-(3-(1-EZ-octenyl)phenyl)- 4,4'-[3-(3-(1-EZ-octenyl)phenyl)-2-2-propyn-1-ylidenebis(oxy)]bis propyn-1-ylidenebis(oxy)](butanol) dibenzoate bis(butanol.sup.c______________________________________ .sup.a No chromatographic purification of the residue over silica gel is necessary. .sup.b Caution, compound should be handled with care. .sup.c Each resultant compound was in the form of an oil. EXAMPLE 1 4,4'and 6,6'-(3-Phenyl and 3-Substituted Phenyl-2-Propyn-1-Ylidenebisoxy)Butanoic and Hexanoic Acids ##STR6## Mix pyridinium dichromate (0.95-1.53M, 8-9 mmol/mol of acetal) and add a hydroxyacetal (4.3 to 13.3 mmol, 0.11 to 0.20M) from Preparative Example 6 in DMF at 25° C. and oxidize for 24-67 hours. Dilute with ten times its volume of H 2 O and filter through diatomaceous earth. Extract the filtrate with ether and combine the extracts. Wash the extracts with H 2 O and brine. Filter the dried ether solutions and evaporate the solvent. Chromatograph the crude product over silica gel (100 g/g) with chloroform:methanol:acetic acid (98:1.8:0.2), and combine the fractions to maximize purity, not yield. Dry in vacuo to yield the title compound, shown in Table VIII below and verify purity with TLC and 1 H-NMR. TABLE VIII______________________________________4-4'- AND 6,6' (3-PHENYL AND 3-(4-SUBSTITUTEDPHENYL)-2-PROPYN-1-YLIDENEBISOXY)BISBUTANOICAND HEXANOIC ACIDS ##STR7##R.sup.3 = H, X = OR.sup.1 m & n Title Compound m.p.______________________________________--H 2 4,4'-(3-phenyl-2-propyn-1-ylidene 72-75° C. bisoxy)bisbutanoic acid (Yield 24%)--H 4 6,6'-(3-phenyl-2-propyn-1-ylidene 62-65° C. bisoxy)bishexanoic acid (Yield 17%)4-hexyl 2 4,4'-(3-(4-hexylphenyl)-2-propyn- 69-72° C. 1-ylidenebisoxy)bisbutanoic acid (Yield 9%).sup.a4-hexyl 4 6,6'-(3-(4-hexylphenyl)-2-propyn- oil 1-ylidenbisoxy)bishexanoic acid (Yield 27%)4-heptyl 2 4,4'-(3-(4-heptylphenyl)-2-propyn- 59-63° C. 1-ylidenebisoxy)bisbutanoic acid (Yield 14%)4-heptyl 4 6,6'-(3-(4-heptylphenyl)-2-propyn- 34-36° C. 1-ylidenebisoxy)bishexanoic acid (Yield 39%)4-octyl 2 4,4'-(3-(4-octylphenyl)-2-propyn- 60-62° C. 1-ylidenebisoxy)bisbutanoic acid (Yield 22%)4-octyl 4 6,6'-(3-(4-octylphenyl)-2-propyn- 41.5-43° C. 1-ylidenebisoxy)bishexanoic acid (Yield 26%)4-nonyl 2 4,4'-(3-(4-nonylphenyl)-2-propyn- 49-50° C. 1-ylidenebisoxy)bisbutanoic acid (Yield 41%)4-nonyl 4 6,6'-(3-(4-nonylphenyl)-2-propyn- 54-56° C. 1-ylidenebisoxy)bishexanoic acid (Yield 32%)4-decyl 2 4,4'-(3-(4-decylphenyl-2-propyn-1- 72-75° C. ylidenebisoxy)bisbutanoic acid (Yield 26%)4-decyl 4 6,6'-(3-(4-decylphenyl)-2-propyn-1- oil ylidenebisoxy)bishexanoic acid (Yield 25%)3-(2- 2 4,4'-(3-(2-(1-EZ-octenyl)phenyl-2- 70-77° C.(1-EZ- propyn-1-ylidenebisoxy)bisbutanoicoctenyl)) acid3-(3- 2 4,4'-(3-(3-(1-EZ-octenyl)phenyl-2- 60-63° C.(1-EZ- propyn-1-ylidenebisoxy)bisbutanoicoctenyl)) acid______________________________________ EXAMPLE 2 Preparation of 4,4' AND 6,6'-(3-Phenyl and 3-(4-Substituted Phenyl)-2-Propyn-1-Ylidenebisthio)Bisbutanoic and Bishexanoic Acids Add BF 3 diethyl etherate (4-40 mmol, 0.4M in CH 2 Cl 2 ) slowly to a -60° C. solution of the title compound of Preparative Example 6 (2-20 mmol, 0.2M) and 4-mercaptobutanoic acid (J. Org. Chem. 28; 1903 (1963)) (4-60 mmol, 0.4-0.6M in CH 2 Cl 2 (distilled from P 2 O 5 ). Stir the reaction mixture at -60° C. for 1 hour and at -20° C. for 15 min. Dilute the reaction mixture to three times its volume with water, and extract with ether. Combine the extracts, wash with H 2 O, dry and filter. Evaporate the solvents, dry in vacuo and chromatograph the residue over silica gel (120 g/g) with chloroform:methanol:acetic acid (98-1.8-0.2) to yield the title compound in Table IX below. TABLE IX______________________________________4,4' AND 6,6'-(3-PHENYL AND 3-(2, 3 OR 4-SUBSTITUTEDPHENYL)-2-PROPYN-1-YLIDENEBISTHIO)BISBUTANOICAND BISHEXANOIC ACIDS ##STR8##R.sup.3 = H, X = SR.sup.1 m & n Title Compound m.p.______________________________________--H 2 4,4'-(3-phenyl-2-propyn-1-ylidene- oil bisthio)bisbutanoic acid.sup.a (Yield 83%)4-hexyl 2 4,4'-(3-(4-hexylphenyl)-2-propyn-1- oil yl-idenebisthio)bisbutanoic acid (Yield 85%)4-heptyl 2 4,4'-(3-(4-heptylphenyl)-2-propyn-1- oil ylidenebisthio)bisbutanoic acid (Yield 62%)4-octyl 2 4,4'-(3-(4-octylphenyl-2-propyn-1- oil ylidenebisthio)bisbutanoic acid.sup.a (Yield 72%)4-nonyl 2 4'4'-(3-(4-nonylphenyl)-2-propyn-1- oil ylidenebisthio)bisbutanoic acid.sup.a (Yield 75%)4-decyl 2 4,4'-(3-(4-decylphenyl)-2-propyn-1 oil ylidenebisthio)bisbutanoic acid.sup.a,b (Yield 81%)2-octyl 2 4,4'-(3-(2-octylphenyl)-2-propyn-1- 56-58° C. ylidenebisthio)bisbutanoic acid (Yield 60%)2-(1-EZ- 2 4,4'-(3-(2-(1-EZ-octenyl)phenyl)-2- oiloctenyl) propyn-1-ylidenebisthio)bisbutanoic acid (Yield 71%)3-(1-EZ- 2 4,4'-(3-(3-(1-EZ-octenyl)phenyl)-2- oiloctenyl) propyn-1-ylidenebisthio)bisbutanoic acid (Yield 48%)4-(1-EZ- 2 4,4'-(3-(4-(1-EZ-octenyl)phenyl)-2- oiloctenyl) propyn-1-ylidenebisthio)bisbutanoic acid (Yield 20%)______________________________________ .sup.a Purified by chromatography over silica gel (240 g/g) and elution with chloroform:methanol:acetic acid (99:0.9:0.1) Isolate the pure compound after evaporating the solvent and triturating with pet. ether. EXAMPLE 3 4,4'-(3-(4-Octylphenyl)-2-Propyn-1-Ylidinebisthio)Bispentanoic Acid ##STR9## Combine in solution 1-(3,3-diethoxy-2-propynyl)-4-octyl benzene (0.505 g, 1.6 mmol) and 4-mercaptopentanoic acid (J. Org. Chem. 28; 1903 (1963)) (0.455 g, 2.0 mmol) in methylene chloride (12 mL), and BF 3 diethyl etherate (0.1 mL) at -40° C. Stir the reaction mixture at this temperature for one hour. Treat the reaction mixture with water and extract with methylene chloride (3×). Combine the organic phases, wash with brine (2×) and dry over Na 2 SO 4 . Remove the solvent and chromatograph the residue with silica gel and ethyl acetate:acetic acid:chloroform (5:0.5:100) to give the title compound as an oil. (Yield 77%, 0.6 g.). The following formulations exemplify some of the dosage forms in which the compounds of the invention may be employed. In each, the active ingredient is 4,4'-(3-(4-hexylphenyl-2-propyn-1-ylidenebisoxy)bishexanoic acid and is referred to as "Active Compound". However, it is to be understood that any other compound of the invention could be substituted. Consequently, the scope of the fomulation examples is not to be limited thereby. Pharmaceutical Dosage Form Examples Example A ______________________________________TabletsNo. Ingredient mg/tablet mg/tablet______________________________________1. Active compound 100 5002. Lactose USP 122 1133 Corn Starch, Food Grade, 30 40 as a 10% paste in Purified Water4. Corn Starch, Food Grade 45 405. Magnesium Stearate 3 7 Total 300 700______________________________________ Method of Manufacture Mix Item Nos. 1 and 2 in a suitable mixer for 10-15 minutes. Granulate the mixture with Item No. 3. Mill the damp granules through a coarse screen (e.g., 1/4") if needed. Dry the damp granules. Screen the dried granules if needed and mix with Item No. 4 and mix for 10-15 minutes. Add Item No. 5 and mix for 1-3 minutes. Compress the mixture to appropriate size and weight on a suitable tablet machine. Example B ______________________________________CapsulesNo. Ingredient mg/capsule mg/capsule______________________________________1. Active compound 100 5002. Lactose USP 106 1233. Corn Starch, Food Grade 40 704. Magnesium Stearate NF 4 7 Total 250 700______________________________________ Method of Manufacture Mix Item Nos. 1, 2 and 3 in a suitable blender for 10-15 minutes. Add Item No. 4 and mix for 1-3 minutes. Fill the mixture into suitable two-piece hard gelatin capsules on a suitable encapsulating machine. Example C ______________________________________Ingredient mg/vial mg/vial______________________________________Active Compound Sterile Powder 100 500______________________________________ Example D ______________________________________InjectableIngredient mg/vial______________________________________Active Compound 100Methyl p-hydroxybenzoate 1.8Propyl p-hydroxybenzoate 0.2Sodium Bisulfite 3.2Disodium Edetate 0.1Sodium Sulfate 2.6Water for Injection q.s. ad 1.0 ml______________________________________ Method of Manufacture (for 1000 vials) 1. Dissolve p-hydroxybenzoate compounds in a portion (85% of the final volume) of the water for injection at 65°-70° C. 2. Cool to 25°-35° C. Charge and dissolve the sodium bisulfite, disodium edetate and sodium sulfate. 3. Charge and dissolve active compound. 4. Bring the solution to final volume by added water for injection. 5. Filter the solution through 0.22 membrane and fill into appropriate containers. 6. Finally sterilize the units by autoclaving. Example E ______________________________________Nasal Spray mg/ml______________________________________Active Compound 10.0Phenyl Mercuric Acetate 0.02Aminoacetic Acid USP 3.7Sorbitol Solution, USP 57.0Benzalkonium Chloride Solution 0.2Sodium Hydroxide 1N Solution to --adjust pHWater Purified USP to make 1.0 ml______________________________________ Example F ______________________________________OintmentFormula mg/g______________________________________Active Compound 1.0-20.0Benzyl Alcohol, NF 20.0Mineral Oil, USP 50.0White Petrolatum, USP to make 1.0 g______________________________________ Method of Manufacture Disperse active compound in a portion of the mineral oil. Mix and heat to 65° C., a weighed quantity of white petrolatum, the remaining mineral oil and benzyl alcohol, and cool to 50°-55° C. with stirring. Add the dispersed active compound to the above mixture with stirring. Cool to room temperature. Example G ______________________________________CreamFormula mg/g______________________________________Active Compound 1.0-20.0Stearic Acid, USP 60.0Glyceryl Monostearate 100.0Propylene Glycol, USP 50.0Polyethylene Sorbitan Monopalmitate 50.0Sorbitol Solution, USP 30.0Benzyl Alcohol, NF 10.0Purified Water, USP to make 1.0 g______________________________________ Method of Manufacture Heat the stearic acid, glyceryl monostearate and polyethylene sorbitan monopalmitate to 70° C. In a separate vessel, dissolve sorbital solution, benzyl alcohol, water, and half quantity of propylene glycol and heat to 70° C. Add the aqueous phase to oil phase with high speed stirring. Dissolve the active compound in remaining quantity of propylene glycol and add to the above emulsion when the temperature of emulsion is 37°-40° C. Mix uniformly with stirring and cool to room temperature. ______________________________________Formulation III: GelFormula mg./g______________________________________Active Compound 1.0-20.0Propylene Glycol, USP 300.0Butylated Hydroxytoluene 5.0Carbomer 940 5.0Sodium Hydroxide (added as a 1% w/w 0.7solution in proplyene glycol)Polyethylene Glycol 400, USP 669.3-688.______________________________________ Procedure Prepare a 1% solution of the sodium hydroxide in propylene glycol and hold. Add approximately one-half the remaining propylene glycol, and the polyethylene glycol 400 to a suitable vessel and mix. Dissolve the butylated hydroxytoluene in this mixture. Disperse the carbomer 940 in the above mixture with vigorous agitation. Add the solution of sodium hydroxide with high speed agitation to bring pH up to 7 and recirculation until a thick gel forms. Dissolve the active compound in the remaining propylene glycol and add to the gel slowly as the gel is continuously recirculated. ______________________________________Formulation IV: LotionFormula mg/g______________________________________Active Compound 1.0-20.0Carbomer 940 3.0Sodium hydroxide (charged as 4% w/w 0.05aqueous solution)Isopropyl Alcohol 40.00Purified Water, USP to make 1.0 g______________________________________ Procedure Prepare a 4% solution of sodium hydroxide in water. Heat the purified water to 60° C. Add carbomer 940 and mix at high speed until dispersed. Cool the above mixture to room temperature and slowly charge sodium hydroxide until uniform. Add 80% of isopropyl alcohol to the above with mixing. Dissolve the active compound in remaining isopropanol. Add this to the mixture with stirring. Adjust pH to 5.0 to 5.5 with sodium hydroxide, if necessary. ______________________________________Formulation V: Topical AerosolFormula mg/g______________________________________Active Compound 1.0-20.0Caprylic/Capric Triglyceride 50.00Mineral oil 20.00Specially Denatured Alcohol 150.00Hydrocarbon Aerosol Propellant 1.0 gq.s. ad.______________________________________ Procedure Add and mix the caprylic/capric triglyceride mineral oil and specially denatured alcohol in a suitable compounding tank. Add the active compound drug and continue mixing until the active compound is dissolved or dispersed uniformily. Fill the concentrate into cans and then fill the required amount of hydrocarbon aerosol propellant. While the invention has been described herein in light of specific examples and embodiments, numerous modifications and alterations will be obvious to those skilled in the art from the teachings herein. All such modifications are included herein as falling within the scope of the claims. Consequently, the scope of the claims is not to be limited thereby.
Phenyl acetylenic acetals and thioacetals and their use in the treatment of allergy, asthma, inflammation, arthritis, hyperproliferative skin disease, psoriasis or contact dermatitis are disclosed. Also disclosed are intermediates useful for producing said phenyl acetylenic acetals and thioacetals.
2
BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a process for producing highly pure 2,6-naphthalene dicarboxylic acid which is useful as a raw material for highly functional polymers, such as highly functional polyesters, polyamides and liquid crystal polymers. 2. Prior Art Prior arts on the production of 2,6-naphthalene dicarboxylic acid (hereinunder referred to as 2,6-NDA) are generally of the following three types. (1) Processes for producing 2,6-NDA which comprise oxidizing a 2,6-dialkyl naphthalene in the presence of a catalyst comprising a heavy metal and a bromine compound are disclosed in U.S. Pat. No. 3,856,855 and Japanese Patent Application Publication (Kokai) No. 34153/1973. (2) A process for producing 2,6-NDA which comprises oxidizing 2,6-diisopropyl naphthalene in the presence of a catalyst comprising Co and Mn is disclosed in Japanese Patent Application Publication (Kokai) No. 89445/1985. (3) Processes for producing 2,6-NDA which comprise oxidizing a 2-alkyl-6-acyl naphthalene in the presence of a catalyst containing Co and Br or Co, Mn and Br or one of these catalysts further containing Fe or Cu are disclosed in Japanese Patent Application Publication (Kokai) Nos. 61946/1987 and 67048/1987 and U.S. Pat. Nos. 4,764,638 and 4,886,906. The 2,6-NDA obtained by these oxidation methods contains impurities, such as intermediates, such as aldehydes, acyl naphthoic acid, etc.; oxidized polymers; colored materials and the like. Since a highly pure raw material is not necessarily used in the commercial manufacture of 2,6-NDA industrially, the product results in containing impurities contained in the raw material. When polyesters, polyamides and liquid crystal polymers are produced from the 2,6-NDA containing impurities as mentioned above, films or fibers obtained from these polymers have poor physical properties such as poor thermal resistance, mechanical strength and dimension stability, and quality in these films or fibers are likely to be lowered due to the discoloration. Therefore, the production of 2,6-NDA which is more than 99% pure has been demanded. Prior arts on the purification of the 2,6-NDA obtained by the above-mentioned methods are as follows: (1) a process which comprises dissolving the crude 2,6-NDA in an aqueous alkaline solution, concentrating the solution to deposit the dialkali salt of 2,6-NDA, dissolving the dialkali salt in water, bubbling a carbon dioxide gas into the solution to deposit the monoalkali salt of 2,6-NDA, dissolving the separated monoalkali salt in water and disproportionating the monoalkali salt by heating it, thereby depositing 2,6-NDA [refer to Japanese Patent Publication (Kokoku) No. 13096/1970]. (2) a process which comprises dissolving the crude 2,6-NDA in an aqueous alkaline solution, carrying out catalytic hydrogenation of the 2,6-NDA in the presence of palladium, platinum, ruthenium or the like as a catalyst at a temperature of not more than 220° C., bubbling a carbon dioxide gas into the solution to deposit the monoalkali salt of 2,6-NDA, dissolving the separated monoalkali salt in water and disproportionating the monoalkali salt by heating it, thereby depositing 2,6-NDA [refer to Japanese Patent Publication (Kokoku) No. 36901/1982]. (3) a process which comprises dissolving the crude 2,6-NDA in an aqueous alkaline solution, heating the solution at 100°-250° C., decoloring the 2,6-NDA solution with activated carbon, concentrating the solution to deposit the dialkali salt of 2,6-NDA, dissolving the dialkali salt in water and adding an acid to the solution to deposit the object product [refer to Japanese Patent Application Publication (Kokai) No. 54051/1973]. (4) a process which comprises adding the crude 2,6-NDA to an aqueous solution containing an alkali and a neutral salt containing the same cation constituting the alkali compound, agitating the solution to deposit the dialkali salt of 2,6-NDA, dissolving the separated dialkali salt in a 1-3 wt % aqueous solution of sodium chloride, treating the solution with activated carbon and depositing the object product with carbon dioxide or sulfurous acid gas [refer to U.S. Pat. No. 4,794,195]. (5) a process which comprises dissolving the crude 2,6-NDA in an organic solvent, such as N,N-dimethyl acetamide, N,N-dimethyl formamide, dimethyl sulfoxide or the like at 80°-189° C., treating the solution with activated carbon and cooling the solution to -15° to 40° C. to recrystallize the object product [refer to Japanese Patent Application Publication (Kokai) No. 230747/1987]. However, in processes (1) and (2), it is difficult to control the proportion of the components constituting crystal and the amount of monoalkali salt of 2,6-NDA due to the delicate equilibrium between (a) an monoalkali salt of 2,6-NDA and a dialkali salt of 2,6-NDA and (b) an acid in the step for depositing the monoalkali salt by adjusting the pH. In addition, since the monoalkali salt of 2,6-NDA is water soluble, the monoalkali salt is eluted in washing with water, the mother liquor which has adhered to the crystal after filtration. This results in a lowering of the yield of 2,6-NDA. In processes (3) and (4), a fine particle size crystal having a size as small as 1 μm is deposited when depositing the object product with an acid. As a result, it becomes difficult to filter or rinse the cake. In process (5), a large amount of an expensive organic solvent such as N,N-dimethyl acetamide, N,N-dimethyl formamide, or dimethyl sulfoxide must be used. In addition, it is difficult to treat such an organic solvent, due to the odor and toxicity of these solvent. Therefore, it is difficult to carry out process (5) on a commercial scale. It is impossible to purify 2,6-NDA by distillation, because the compound has a melting point of not less than 300° C. As mentioned above, it is difficult to obtain highly pure 2,6-NDA by purifying the crude 2,6-NDA. Therefore, the present inventors have attempted the production of highly pure 2,6-NDA by esterifying crude 2,6-NDA, followed by hydrolyzing the resulting dimethyl ester of 2,6-NDA (hereinunder referred to as 2,6-NDM). 2,6-NDM can be purified by distillation. In addition, it is easy to recrystallize 2,6-NDM and treat 2,6-NDM with a solid adsorbent, since 2,6-NDM is easily dissolved in an organic solvent. 2,6-NDM itself is used as a raw material for polyester. Therefore, the purification of 2,6-NDM has been established. Hydrolysis or saponification is used for producing 2,6-NDA from 2,6-NDM. However, when 2,6-NDM is saponified, the dialkali salt of 2,6-NDA is formed. The above-mentioned problem occurs in case of deposit the dialkali salt of 2,6-NDA with an acid. The hydrolyzing operation proceeds slowly in the absence of any catalyst. When 2,6-NDM is hydrolyzed in the presence of a generally used mineral acid such as sulfuric acid as a catalyst, the reaction proceeds rapidly. However, the resulting crystal is too fine for filtering or washing. SUMMARY OF THE INVENTION The present inventors have conducted further research to obtain a highly pure 2,6-NDA. As a result, when an aromatic poly-carboxylic acid is used as a catalyst instead of a mineral acid, it is found that the reactivity is high, and that the resulting 2,6-NDA crystal is large enough to be filtered or rinsed. The present invention is based on this finding. This invention relates to a process for producing highly pure 2,6-naphthalene dicarboxylic acid, characterized by hydrolyzing 2,6-dimethyl naphthalene dicarboxylate more than 99% pure in an aqueous solution by using an aromatic poly-carboxylic acid or an anhydride thereof as a catalyst. DETAILED DESCRIPTION OF THE INVENTION 2,6-NDM which is used as a raw material in the present invention can be produced by oxidizing a 2,6-dialkyl naphthalene or a 2-alkyl-6-acyl naphthalene as mentioned above, thereby forming 2,6-NDA, followed by esterifying the resulting 2,6-NDA in the presence of sulfuric acid (catalyst) in a methanol solvent at 100°-200° C. 2,6-NDM can be purified by distillation, both of distillation and treatment with a solid adsorbent; or recrystallization. Purity of the purified 2,6-NDM was measured by chemical analysis such as gas chromatography or high speed liquid chromatography. The amount of water used in the solution in the present invention may be 2-15 times by weight of the amount of 2,6-NDM, and preferably 5-10 times by weight of the amount of 2,6-NDM. If the amount of water is less than 2 times by weight, the concentration of methanol formed by the hydrolysis becomes high, and as a result, high reactivity cannot be achieved due to the poor equilibrium. If the amount of water is more than 15 times by weight, reactivity does not change. This is not economical. Examples of the aromatic poly-carboxylic acids include phthalic acid, trimellitic acid, pyromellitic acid and the like. The anhydrides thereof can be used. The acid can be used alone or as a mixture. The concentration of the aromatic poly-carboxylic acid may be in the range of 2-20% by weight and preferably 2.5-15% by weight. If the concentration of the aromatic poly-carboxylic acid is less than 2% by weight, the reaction speed is slow. If the concentration of the carboxylic acid is more than 20% by weight, this is not economical, due to the lack of change in the reactivity. The reaction temperature may be in the range of 200°-230° C., and preferably 210°-220° C. If the reaction temperature is less than 200° C., the action of the catalyst is lowered, and as a result, the reactivity is lowered. If the reaction temperature is more than 230° C., corrosive action of the carboxylic acid shall be stronger, and as a result, the carboxylic acid corrosion shall be occurred on the surface of the vessel material. The reaction pressure may be such a pressure that the reaction system is maintained to a liquid phase. Therefore, the reaction pressure depends on the reaction temperature. The present reaction may be carried out in an inert gas not containing oxygen. If oxygen is present in the gaseous phase in the reaction vessel, the 2,6-NDM is likely to be discolored, and decomposition of the aromatic poly-carboxylic acid is promoted. When the present reaction is carried out at the above-mentioned temperature range in an inert gas, the aromatic poly-carboxylic acid is stable, and it is observed that decomposition of the carboxylic acid after the reaction hardly occurs. After the reaction is completed, the reaction mixture is cooled to about 80° C. to crystallize the 2,6-NDA. The 2,6-NDA is separated from the mother liquor by filtration, and is rinsed with hot water to remove the mother liquor and deposited catalyst from the crystal, thereby obtaining highly pure 2,6-NDA in a high yield. According to the present invention, highly pure 2,6-NDA can be obtained without using a large amount of alkali, which remains as an inorganic ion in the object product, or any expensive solvent. In addition, since 2,6-NDA is hardly dissolved in water, 2,6-NDA is not eluted in the separated mother liquor and a rinsing solution as the case of alkaline or organic solvent. The 2,6-NDA crystal particles which are obtained by hydrolyzing 2,6-NDM in the presence of an aromatic poly-carboxylic acid as a catalyst have a large particle size. Therefore, it is easy to wash the separated cake and there is few or no crystal particles which pass through the filter during filtration, and as a result, all or most of the crystal particles purified can be recovered. Therefore, the present invention has the following advantages: (1) The recovery rate of 2,6-NDA is strikingly high; (2) The operation of the present invention is easy; (3) Any alkali or any expensive solvent are not used; and (4) It is unnecessary to treat the exhaust formed by the present invention. Consequently, the present invention is excellent from an industrial point of view. This invention is further explained by way of the following non-limiting examples. All percentages are on a weight basis, unless specified otherwise. EXAMPLE 1 Into a 100-ml zirconium autoclave were charged 60 g of water, 10 g (14.2% solution in an solvent) of pyromellitic acid and 10 g of 2,6-NDM. The gaseous phase in the autoclave was purged with nitrogen. The 2,6-NDM used was prepared by the process which comprises: a step of oxidizing 2-methyl-6-butylnaphthalene to form 2,6-NDA; a step of esterifying the 2,6-NDA with a 1% sulfuric acid solution in methanol to form crude 2,6-NDM 99% pure; and a step of distillation of the crude 2,6-NDM to form white 2,6-NDM. The autoclave was placed in an aluminum block heater, and the hydrolysis was carried out at 220° C. for 2 hours while agitating the mixture by shaking the autoclave. After the reaction was completed, the mixture was cooled to 80° C. and then the autoclave was opened. Thereafter, the reaction mixture was filtered and the product was rinsed and dried. The resulting crystal particles were white. When the particle size distribution of the crystal particles was measured, the average particle size thereof was 60 μm and the uniformity index thereof was 2.2. A color-difference meter showed an L-value of 97.0, a-value of -0.3 and b-value of 3.7. Gas chromatograph analysis did not reveal the presence of any impurity. The acid value thereof 519 mg KOH/g (theoretical acid value of 2,6-NDA is 519 mg KOH/g). These analytic data show that the resulting 2,6-NDA was pure. The product (9.39 g) was obtained, and the yield was 99%. EXAMPLE 2 The procedure of Example 1 was repeated except that pyromellitic acid (5 g) was used, and hydrolysis was carried out at 210° C. for 4 hours. The results are shown in Table 1. EXAMPLES 3-5 The procedures of Example 1 were repeated except that trimellitic acid (Examples 3-4) and phthalic acid (Example 5) were used instead of pyromellitic acid. The results are shown in Table 1. CONTROL RUNS 1-3 The procedures of Example 1 were repeated except that sulfuric acid was used instead of pyromellitic acid. TABLE 1__________________________________________________________________________ Example Control Run 1 2 3 4 5 1 2 3__________________________________________________________________________Catalyst amount pyromellitic pyromellitic trimellitic trimellitic phthalic sulfuric sulfuric sulfuric(g) acid acid acid acid acid acid acid acid 10 5 10 1.5 10 1 1 1Reaction 220 210 220 220 220 220 210 200temperature (°C.)Reaction time (hr.) 2 4 2 3 3 2 2 4Acid value (mg KOH/g) 519 518 519 518 519 519 518 518Color L 97.0 97.0 97.1 97.0 97.3 97.0 96.4 97.3 a -0.3 -0.1 -0.3 -0.5 -0.5 -0.3 -0.3 -0.3 b 3.7 3.0 3.2 3.3 3.3 3.7 2.6 3.0Average particle 60 57 59 51 67 25 27 27size (μm)Uniformity index 2.2 1.9 1.8 1.5 1.6 1.2 1.3 1.2Yield (%) 99 98 98 97 99 75 76 73__________________________________________________________________________ CONTROL RUN 4 The procedure of Example 1 was repeated except that the hydrolysis was carried in the absence of any acidic catalyst. The acid value of the resulting 2,6-NDA was 140 mg KOH/g, and its yield was 40%. CONTROL RUN 5 The procedure of Example 3 was repeated except that the gaseous phase in the autoclave was not purged with nitrogen. The resulting reaction liquid was brown, and the separated 2,6-NDA crystal was light red. Color-difference meter showed an L-value of 95.2, a-value of 0.1 and b-value of 6.0. This example means that oxygen in the gaseous phase in the autoclave gives a bad effect to the color of the resulting product.
A process for producing highly pure 2,6-napthalene dicarboxylic acid, characterized by hydrolyzing 2,6-dimethyl naphthalene dicarboxylate more than 99% pure in an aqueous solution by using an aromatic poly-carboxylic acid as a catalyst is disclosed.
2
FIELD OF THE INVENTION The present invention relates, in general, to sewing machines and is more particularly concerned with a lubrication system for sewing machines. BACKGROUND OF THE INVENTION In modern sewing machines, particularly of the industrial type, it is frequently desirable to use high speed operation. When using high speed operations, however, a problem may result in that moving parts within the frame of the machine have a tendency to overheat, with resulting deterioration of lubricant and parts of the machine. Lubricating systems have been suggested in which there is provided means for supplying lubricant to the various areas of the machine, but without any regard for the quantities of lubricant that are being delivered to the various mechanisms. In this regard, these known systems have the drawback of supplying surplus quantities of lubricant in order to insure lubrication of the bearings and bushings of and, thus, there is great likelihood of excess lubricant leaking from the bearing surfaces, not only when the machine is running, but also after the machine has come to a stop. In addition, an excess amount of lubricant means that reduntant work is being done in supplying excessive or unnecessary power consumption. Excess heat at the bearing may also occur as a result of surplus lubricant being supplied to the bearing. The quantity of lubricant required by one specific mechanism, i.e. the feed mechanism of the machine, may be different from that required by another mechanism, i.e. the drive mechanism for an operating tool. It has been found that the quantity of lubricant required for or by each mechanism is dependent upon such variable factors as the dynamic loading characteristics of the mechanism, the desired rate of heat removal, the type of bearings used, etc. Besides its function of reducing friction between bearing components, lubrication may also help to protect the bearings or bushings from corrosion and act as the heat transferring media. To best accomplish these purposes, it is essential that the quantity of lubricant be accurately adapted to the conditions under which the bearings and lubricant must operate. As mentioned, too much lubricant may result in excessive heat generation due to shearing the excess amount of lubricant supplied. Too little lubricant may not maintain an adequate lubricating film within the bearing which may result in abnormal wear and heat build-up. For the reasons discussed herein above, it has been found necessary to conceive and develop a lubrication system which will satisfy all of the requirements set forth above and overcome the drawbacks of the prior systems. SUMMARY OF THE INVENTION The present invention will be particularly described in its application to a sewing machine, although it will be appreciated that many of the principles and techniques advanced herein may be equally applicable to other machines as well. With the machine under consideration, there are a plurality of widely distributed operable mechanisms which require lubrication. Thus, in the presently preferred embodiments, a force flow lubrication system has been found preferable. In order to optimize its anti-frictional and heat dissipation characteristics, the present invention provides means for individually measuring the quantity of lubricant that is delivered to the various mechanism in relatively small, yet accurately proportioned, quantities according to the requirements of the various mechanisms. The metered quantities of lubricant will give sufficient and ample lubrication without overflow or excess lubricant on the machine regardless of the relative inaccessibility or accessibility of the mechanism, varying conditions or various temperatures all of which may change certain characteristics of the lubricant. In the presently preferred form, there is provided a lubricant reservoir and a positive displacement mechanism or pump means, the input shaft or rotor of which may be co-axially aligned with and actuated by an associated mechanism of the machine. The pump means is effective to transmit lubricant under pressure to the operating mechanisms of the machine and for transferring lubricant collected in non-drainable areas of the machine to the lubricant reservoir. Arranged in combination with the displacement means are a series of adjustable restricting means adapted to regulate the flow of lubricant in amounts corresponding to the relatively minute quantities required of the particular mechanism. It may be worthy to note that the adjustable restrictive means may correspond in number to the operating mechanisms arranged in the frame of the machine. In view of the fact that there has been provided a positive displacement pump means in combination with a restrictive control flow mechanism, it has been found desirable to provide a pressure relief valve assembly which is rendered effective when the pressure of the lubricant exceeds some predetermined limit. In this manner, if the lubricant pressure exceeds the upper limit, the pressure relief valve assembly is effective to return the excess lubricant to the reservoir whereby assuring an efficient and effective force feed lubrication system by maintaining the lubricant pressure within the machines' operating speed ranges. That is, the delivery of lubricant is not dependent upon the speed of the machine. When working in an environment of dust or dirt, it may be appreciated that regardless of the care utilized in maintaining a clean supply of lubricant in the machine reservoir it may invariably become contaminated, to some degree, by a form of foreign matter. It was found desirable, therefore, to provide a dual filtering system. The dual filtering system includes a first stage filter that is adapted to filter large contaminants and a second stage filter. The second stage filter is adapted to screen the lubricant immediately prior to its delivery to the restrictive control means of the invention. In view of the close relationship desired between the second stage filter and the metering means, the present invention has provided a modular housing which contains both the filtering apparatus and the metering means, thus facilitating the ease of replacement when necessary. The lubrication system of the present application also incorporates a flow indicator sight gauge. This gauge will readily lend to the machine operator a quick visual indication of the oil flow throughout the lubrication system. In view of the above, it is the primary object of this invention to provide an automatic lubrication system that is simple, economical, effective and dependable and that will provide for operation of the machine at very high speeds. It is also among the particular objects of the present invention to provide a new and improved system of lubrication which is adapted to supply sufficient and ample lubrication without overflow or excess to the various mechanisms of the machine. Another object of this invention is to provide a lubrication system for a machine which will automatically be actuated by a mechanism of the machine and will supply the proper proportions of lubricant to the various mechanisms according to the requirements thereof. It is a further object of the present invention to provide a lubrication system which will operate automatically over long periods of time, without appreciable attention from the operator. Yet another object of this invention is to provide a lubrication system which incorporates adjustable restrictive means whereby small compensatory variations in the flow of lubricant may be made with both ease and accuracy. Another object of this invention is to provide a force flow lubrication system for a machine in accordance with the foregoing objects in which lubricant is presented to the metering means in a filtered state and under a predetermined or pre-set constant pressure. Another object of the present invention is to provide a system of lubrication which is comprised primarily of a multiplicity of modular mechanisms for delivering metered quantities of lubricant under pressure throughout the operation of the machine. BRIEF DESCRIPTION OF THE DRAWING Having in the mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and arrangements of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it when read in conjunction with the accompanying drawings in which; FIG. 1 is a perspective view of a machine incorporating the present invention. FIG. 2 is a fragmentary front elevational view, taken partially in section, illustrating the lubricant pump assembly of the present invention. FIG. 3 is a fragmentary side sectional view, taken along line 3--3 of FIG. 2. FIG. 4 is a fragmentary top sectional view, taken along line 4--4 of FIG. 3. FIG. 5 is an exploded perspective view of the modular lubricant pump assembly. FIG. 6 is an enlarged sectional view showing but a part of the present invention. FIG. 7 is a fragmentary top view, taken partially in section, showing the modular lubricant dispensing means of the present invention. FIG. 8 is a fragmentary front elevational view, taken along line 8--8 of FIG. 7. FIG. 9 is a fragmentary front elevational view, taken along line 9--9 of FIG. 7. FIG. 10 is a fragmentary side elevational view, taken along line 10--10 of FIG. 7. FIG. 11 is a fragmentary top sectional view, taken along line 11--11 of FIG. 10. FIG. 12 is an enlarged sectional view of one element of the present invention. FIG. 13 is a schematic representation of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now in more detail to the drawings in which like reference numerals indicate like parts throughout the several views, the machine within which the present invention is embodied is a high speed industrial sewing machine 10, having a frame comprising a bed 12 which is fitted with a work support plate 14. Rising from the right hand end of the bed portion 12 is a hollow vertical standard 16 which may be secured to the bed by any suitable means. The standard 16 has a hollow arm or bracket 18 extending laterally from its end so as to overhang the bed, the arm 18 having a hollow head 20 at its free end. Within the head 20 there may be provided needle bar means 22 which may be suitably supported for endwise movement and mechanism means (not shown) for reciprocating the needle bar. The mechanism means for reciprocating the needle bar may be of similar construction to that disclosed in U.S. application Ser. No. 908,199 filed May 22, 1978. Rotatably mounted beneath the work support plate 14 and arranged longitudinally of the machine frame 12 in bearings 24, preferably anti-friction bearings, is a lower main or bed shaft 26. The bed shaft 26 extends through a "dry" machine area or mechanism chamber 28 and beyond the end wall of the machine. The outer projecting end of this shaft has suitably secured thereto a combined handwheel and belt pulley means (not shown) about which a belt is adapted to be entrained for the purpose of delivering power to the machine. At its other end, the shaft 26 is associated with the feed mechanism (not shown) of the machine. The feed mechanism may be of any suitable type and well known to one skilled in the art of sewing. Referring now to FIGS. 2 and 3, secured to the open underside of the bed 12 is a lubricant reservoir or cavity means 30 which is adapted to receive the lubricant that is to be delivered to the various operable mechanisms of the machine. The lubricant reservoir means 30 is divided into a main chamber 30a for holding unfiltered lubricant and a smaller chamber 30b for holding filtered lubricant. The smaller chamber, 30b, is defined by wall-like partitions 32 which may be covered by a first stage filter means which, in the presently preferred embodiment, is defined by a large filtering member 34. Lubricant entering or flowing through the filter 34 will thus be filtered in the process, thereby preventing large undesirable contaminants from entering the lubrication system. The filtering member 34 is preferably formed from a layer of screen or other suitable material which may be held in place by a suitably formed plate-like means 35. There may also be provided a transparent site gauge 36 of the type described in U.S. Pat. No. 2,301,460 granted to Sauer on Nov. 10, 1942 for indicating the level of lubricant in the reservoir or cavity means 30. For purposes of this description, the present invention will be described as being embodied in a chainstitch sewing machine, but it will be appreciated that certain aspects of this invention are appropriate for more general applications. One of the identifying features of this specific type of sewing machine is that it is provided with a looper means (not shown) which is adapted to cooperate with the needle means 38 in the formation of chain stitches. In the presently preferred embodiment the looper means is driven by a modular looper drive assembly generally designated in the drawings as 40; the construction of which is incorporated herein by reference from U.S. application Ser. No. 877,065 filed Feb. 13, 1978. As described in said application, the looper drive assembly 40 may be slideably received in the bed portion 12 of the machine. The movement of the looper drive means permits adjustment of the looper avoid motion imparted to the looper. For purposes of this description, suffice it to say that the modular looper drive assembly 40 includes an annular housing means 42 and a stub shaft means 44 suitably supported for rotation within the housing. As seen in FIG. 2, the right end of shaft 44 projects beyond the housing 42 along an axis parallel to the longitudinal axis of the main shaft 26 and is operatively driven thereby. Broadly stated and with reference to the schematic representation shown in FIG. 13, it may be seen that the lubrication system which forms the subject matter of the present invention includes the lubricant reservoir means 30, a modular pump assembly 46 and a lubricant metering assembly 120 including a series of adjustable restrictive valve means and a dual filtering system. As mentioned earlier, one advantage of the present invention is that the entirety of the lubricating system is mounted within the confines of the frame of the machine. The modular lubricant pump assembly best illustrated in FIGS. 2, 3, 4 and 5 is indicated as an entirety by reference numeral 46. The pump assembly may be secured, in an oil-tight fashion, in the "dry" chamber 28 of the machine by any suitable means and is adapted to deliver lubricant under pressure from the reservoir means 30 to a lubricant distribution means, described hereinafter, at substantially constant volumetric quantities over a range of machine speeds. The lubricant pump assembly 46 includes a casing or housing means 48 made up of two complimentary separable pump bodies 50 and 52. The pump bodies are operably separated by partition means 54 interposed therebetween, all of which is held in rigidly assembled relation by a series of retainer means 56. A sealing means 58 is clamped between the pump bodies when assembled for the purpose of preventing lubricant from escaping into the "dry" chamber. The pump assembly 46 preferably comprises two separate positive displacement pump means provided by two pair of gerotor-type assemblies 60 and 62. The gerotor pumps are correspondingly driven with the operation of the machine and are adapted to work in concert with one another. The tandemly mounted gerotor pumps 60 and 62 are slideably mounted on a drive shaft 64, which is received in a sleeve bearing 66 mounted within an opening in the pump body 50. One end of the drive shaft 64 extends outwardly beyond the pump assembly and is adapted to be driven by a suitable rotary driving component of the machine such as the drive shaft 44 of the looper drive assembly 40. With the present invention, it has been found preferable to axially align shafts 64 and 44 so as to minimize the radial forces and bending moment applied to the bearings supporting the shaft 64. A type of flexible coupling 68 is used for operatively connecting the shaft 64 with the drive means. As best seen in FIG. 5, with the present embodiment, the gerotor pump 60 is defined as a first stage low pressure pump assembly which includes intermeshing inner and outer rotor elements 70 and 72, respectively. The inner rotor 70 has a spline-type connection with the transmission shaft 64, said connection including a key or pin means 74 which may be accomodated in an elongated recess 75 formed on the periphery of shaft 64. The pin 74 also engages a correspondingly formed keyway 77 in rotor element 70 such that upon rotation of shaft 64 the inner rotor 70 rotates therewith. Each of the inner faces of the pump bodies is eccentrically formed with a cylindrical recess means 70 into which is seated the outer element or rotor 72. As may be appreciated by one skilled in the art, the annular rotor 72 may be allowed some degree of free rotation within the recess 79. The other gerotor pump 62 acts as a second stage higher pressure pump assembly which can be housed within the pump body 52. The higher pressure pump assembly 62 is similarly constructed to the lower pressure pump assembly 60 in that it includes inner and outer rotor elements 70' and 72', respectively. The inner rotor 70' is drivingly connected to shaft 64 through an extension of pin 74. The inner element 70' is adapted to intermesh with the outer element 72' which, in turn, may be received in the above mentioned eccentrically arranged recess. It may be seen from the drawings that the pump assemblies 60 and 62 are operatively separated by a partition or separator means 54. In the presently preferred embodiment, the separator means 54 is formed as a stepped disc-shaped body which may be interposed and clamped between the respective pump assemblies. It should be noted that the separator or partition means has a dual function. First, the separator is adapted to retain the pump assemblies 60 and 62 and the pin 74 as a unitary assembly while allowing, if necessary, for the pump or shaft 64 to be axially shifted a limited extent with respect to the housing or casing 48. Maintaining the pumps and pin as a unitary assemblage may be accomplished by providing the partition 54 with a cylindrical bore 80 which, when mounted on shaft 64, surrounds a reduced shoulder or lateral notch 82 formed on the periphery of pin 74, thus fixedly holding the rotors 70 and 70' and pin 74 in a fixed relationship relative to housing 48 when the shaft is axially moved. It should be appreciated that the axial adjustment of the shaft 64 may be controlled within limits by a series of retainer means 86 and 88. As is apparent from FIG. 2, the retainer means 86 limits the movements of shaft 64 to the right while retainer means 88 controls the extent of movement of the shaft to the left. The retaining means 88 is arranged at the right end of shaft 64 and is adapted to engage the pin 74 when the shaft 64 has reached the limits of its movement to the left. That is, the shaft 64 is free to move to the left until such time as the free length of the elongated recess 75 is traversed, at which time the right end of pin 74 will engage the retaining means 88. The free or axial movement of the shaft is necessary so as to allow adjustment of the looper avoid motion as was discussed above. The second function served by the partition 54 is that it is adapted to allow each of the pumps 60 and 62 to act independently of the other thus improving the operating characteristics of the pump assembly 46 as a whole. This second function is accomplished by adapting the separator 54 so that it may maintain the pumps 60 and 62 in their proper working relationship relative to the housing 48 and by sealing one pump assembly from another. Each of the pump bodies is provided with inlet and outlet ports 90 and 92, respectively, and suitable lubricant passageways 94 whereby allowing communication between the gerotor pumps and the inlet and outlet ports. It should be noted that the inlet and outlet ports 90 and 92 for the pump assemblies are aligned with suitable passages 96 arranged in the bed 12 so as to allow communication between the pump and the lubricant reservoir 30. As may be appreciated, during the rotation of shaft 64, the gerotor pump 62 is operated whereby effecting the transmission of lubricant from the reservoir 30 to the inlet port 90 through suitable conduit means such as pipe 98. Since the pump assembly 46 is a positive displacement mechanism, the output flow thereof is proportional to the revolutions per minute imparted to the shaft or rotor 70'. The expansion and contraction of the displacement pockets between the rotors 70' and 72' produces volume changes which are essentially constant and which force lubricant from the inlet port 90 and deliver same under pressure to the outlet port 92. Leading from the discharge side of the pump is a conduit 100 which may be adapted to conduct the pressurized lubricant to a suitable cooling means (not shown) wherein the temperature of the lubricant, if necessary, is controlled. Once the relative usefulness of the lubricant has expired, it simply gravitates back to the reservoir in that the lubricant is a given entity, that is, it is not affected by evaporation or condensation. As may be appreciated, however, there may be some areas in the machine frame which may be non-drainable, that is, the expired lubricant collects in these areas rather than draining to the machine reservoir. In this regard, it has been found desirable to provide the first stage lower pressure pump assembly 60 for positively transmitting lubricant from the non-drainable areas of the machine so as to return same to the reservoir 30. To this end, secured to the inlet port of pump assembly 60 is a conduit means 102. The lubricant conduit 102 is adapted to allow communication between the various non-drainable areas of the machine and the pump assembly 60. In operation, the actuation of pump assembly 60 is effective to transmit or draw any excess lubricant in the various non-drainable areas through the conduit 102 and to exhaust same, under pressure, from the outlet port back to the reservoir 30. From the above description, it is apparent that there is provided a new and improved lubricant pump assembly for forcibly delivering lubricant to the various operable mechanisms of the machine and for establishing means for transmitting any excess lubricant from any non-drainable areas of the machine to the lubricant reservoir. Since the pump assembly 46 is a positive displacement mechanism which is used in combination with a lubricant metering means, it will be understood that the lubricant which exists in the space between the sleeve bearing and the shaft may be subjected to increasing pressure as the pump rotates. As is well known, the flow of any liquid follows a path of least resistance and, therefore, some lubricant may be forced outwardly along the bearing surface between the shaft 64 and the bearings. As mentioned above, in this preferred embodiment, the sleeve bearing 66 may be plugged and, therefore, will not allow the escapement of lubricant. However, bearing means 66' is not plugged and, therefore, it is possible for lubricant to escape to the periphery of the housing 48 via the bearing surface. Since the pump assembly 46 is disposed in a "dry" chamber, it is desirous to provide means which insure that the lubricant will not be allowed to escape beyond the periphery of the housing. Toward this end, and as may be best seen in the FIG. 6, the present invention provides means for preventing lubricant from leaking along the bearing surface. The means for preventing lubricant leakage include the sleeve bearing 66' which is formed with a radial port 106 that is arranged to communicate with a conduit 108 formed in the pump housing 50. The housing 50 is also provided with a bore 110 that is adapted to join the conduit 108 with the cylindrical recess 79 formed in the pump housing 50. In this manner, the negative pressure or suction in the cylindrical recess 79, caused by the actuation of the pump assembly 60, is effective to create a draft in the communicable means that is, the bore 110, the conduit 108 and the radial port 106. Accordingly, if any lubricant should be forced along the bearing surface, it will be drawn through the communicable means and directed back to the passageway 94. There may further be provided a needle valve means 112 which can be threadably engaged in the conduit 108 and may be provided with a needle valve stem 114. The needle valve stem may be adapted to expose, to an adjustable degree, a selected portion of the conduit means so as to regulate the flow through the communicable means. The importance of the needle valve toward the present invention is that is provides for adjustment according to the preset operating speed of the machine, thus preventing lubricant from escaping to the periphery of a pump over a range of machine speeds. In order to properly control the flow of lubricant to the various operable mechanisms arranged in the machine frame, and more particularly to optimize the anti-frictional and heat dissipation characteristics of the lubricant, the present invention is provided with a modular lubricant dispensing means generally identified by reference numeral 120. Lubricant is delivered, under pressure, to the modular lubricant dispensing means from the oil cooler or, if preferred, directly from the modular lubricant pump assembly means 46. The lubricant dispensing means 120 is adapted to deliver lubricant in individually and accurately measured amounts to the plurality of operating mechanisms which are spatially arranged in the frame of the machine--i.e., the needle drive mechanism means, the feed mechanism means, the looper drive mechanism means, etc. The lubricant may be applied to the operating mechanisms in any of a variation of well known ways, but it is important to note that the lubricant flow is regulated in amounts corresponding to the minute requirements of the parts to be lubricated. The construction and operation of the modular lubricant dispensing means 120 will now be described in detail. Referring to the drawings, the preferred embodiment of the modular lubricant dispensing means 120 is shown as comprising a one-piece body 122 having a lubricant dispensing portion 124 in which is carried a plurality of adjustable restrictive assembly means 126 and a lubricant filtering portion 128 which includes a second stage filter that is effectively interposed between the lubricant pump assembly 46 and the metering portion 124 and is adapted to prevent any micro sized particles from entering the adjustably restrictive means 126 whereby protecting the anti-friction bearings from abrasive components. It should be mentioned that the adjustable restrictive means correspond in number to the various operable mechanisms which are to be lubricated. In the embodiment under construction, the one-piece body 122 is formed from any suitable material and is secured, in an oil tight fashion, to the bed or frame 12 by any suitable means such as screws 130. The body 122 is shown as having an open ended generally circular cavity 132 into which is fitted a replaceable filtering element or member 134. The filtering element 134 may be of any commercial type, preferably including pleats, i.e., it is folded in a zig-zag form, and has a filtering capacity of approximately 20 microns. As seen in FIG. 9, the body 122 is provided with an aperture 136 which, at one end, receives the lubricant from the lubricant pump assembly 46 while the other end thereof opens into the cavity 132. Thus, the lubricant presented to the lubricant dispensing means is filtered by element 134 before it is presented to the lubricant dispensing portion. A cover 140 is arranged at the open end of the cavity 134 such that the filtering element may be readily accessible and easy to replace. The filtering element 134 is telescopically arranged over an insert piece 142 which is provided with a lubricant communicable bore 144. The body 122 is formed lengthwise with a central flow passage 146 which is arranged in combination with the bore 144 such that the filtered lubricant may flow from the cavity 132 to the dispensing portion 124 of the lubricant dispensing means 120. The dispensing portion of the body 122 is formed with a plurality of apertures 148 which intersect and, thus, communicate with the central flow passage and each of which are adapted to receive the adjustable restricting assembly means 126. Since all of the adjustable restricting means 126 may be substantially the same, the embodiment shown in FIG. 12 will be described as representative of such means. As shown, the adjustable restrictive means 126 includes a valve body 150 and a needle valve means 152 which may be threadably engaged therewith. The valve body 150 is accommodated in a counterbore portion 153 of the aperture 148. The valve body 150 is formed with a radial port 154, joining the central passage 146 with an axial bore 158. The filtered lubricant may flow into the central conduit 146 through the radial bore 154 into the axial bore 158, and then through an outlet conduit 160. From the outlet conduit 160 the lubricant may flow through the aperture 162 and into an output fitting 164 (FIG. 8) threadably arranged in frame 12. A passageway 166 in the output fitting 164 communicates with flexible tubing or piping 168 which maybe provided for directing the lubricant from the distribution means 120 to the various operating mechanisms requiring lubrication. The plumbing internally of the machine is not illustrated in the drawings because this type of plumbing may be of the type which is well known in the art in lubricating systems which are arranged completely within the sewing machine casing. As noted above, the distribution means of the present invention is provided with a needle valve means 152 for regulating the flow of lubricant to the various areas of the machine. Turning again to FIG. 12, it may be seen that the needle valve means of the present invention are preferably adjustably secured in the valve body 159 such that the needle valve stem 170 may be positioned in the outlet conduit means 160 and may be adjusted to expose a selected portion thereof so as to regulate the quantity of lubricant from the central bore 146 to the output connection 164. It may be appreciated, that the upper extremity of the needle valve means may be snuggly accommodated in the aperature 148 and sealing ring 172 may be seated in an annular groove 174 formed in the extremity of the needle valve so as to prevent leakage of lubricant between the needle valve and the aperature 148. As illustrated in FIGS. 10 and 11, the lubricant dispensing means may further be provided with a pressure relief valve assembly means 180 which is rendered effective to maintain a preset or predetermined pressure in the system. For, as mentioned earlier, too little pressure in the system may effect the consistency of the lubricant flow to the operating components of the machine while too much pressure may cause the collapse of the filtering element. With the preferred embodiment, it has been found desirable that a setting of approximately 20 p.s.i. can optimize the flow of lubricant to the various mechanisms of the machine. In the embodiment under construction, the body 122 is provided with two intersecting bores 181 and 182. The bore 181 leads away from the cavity 132 while the aperture or bore 182 is adapted to discharge any lubricant in the bore 181 back to the reservoir. It may be noted from FIG. 10, that the passageway 181 intersects the cavity 132 at a position such that it is adapted to draw off any sediment which may accumulate along the bottom of the cavity. Slidably arranged in the passageway 181 is the pressure relief valve assembly which, in the presently preferred embodiment, includes a valve member 184 that may be somewhat triangularly shaped so that a relatively smooth flow path is provided from the cavity 132 through the member 184 into the discharge passage 182. The member 184 may include a conically shaped end 186 having a generally flat face 188. In the preferred embodiment, and as seen in FIG. 11, a seat or retainer means 190 is arranged at the right hand end of the passageway 181 and is provided with a passage 192 so as to allow the flow of lubricant therethrough. The valve member 184 is continually biased toward the seat 190 by a resilient member 194, preferably a coil spring, which is stressed by an adjustable stop assembly 196 such that lubricant is prevented from flowing into the passage 181 until the lubricant pressure in the system is greater then the magnitude of pressure applied by the spring 194. Although not shown in the drawings, it is well within the scope of the present invention to provide the stop member with a nylon type insert thereby preventing the stop member from moving as a result of machine vibration. If the pressure in the system is greater than that exerted by the influence of the spring, the valve member 184 will permit draining of the excess lubricant, via passage 181, back to the reservoir until such time as the pressure in the system is returned to that set by the pressure relief valve assembly. Although the adjustable stop assembly could take many forms within the scope of this invention, in the present embodiment it comprises a first movable stop member 198 which may be threadably received in the left hand end of the body 122 as viewed in FIG. 11. As shown, the passageway 181 is provided with internal threads which permits the member 198 to be shifted longitudinally in the passageway. Thus, the stop member may be threaded into the body to any desired position by use of a standard tool. As best seen in FIG. 13, there may be provided a visual indicator 151 which will quickly and easily indicate through ocular inspection whether or not there is a flow of lubricant through the system. In the preferred embodiment, the visual indicator 151 is mounted in the upper arm of the machine at a point easily visible to the operator. The indicator is situated such that lubricant, to a limited degree, is splashed thereon as it is delivered to the upper arm of the machine. In operation, rotation of shaft 64 will cause the actuation of the lubricant pump assembly. It is important to note that a minimal reaction force is placed on the bearing 66' journaling the shaft in view of the axial alignment of same with the input power source. The positive action of the gerotor pump serves two purposes. First, the lubricant pump assembly raises the lubricant from the reservoir 30 and delivers same, under pressure, to the lubricant dispensing means 120. Secondly, the action of the pump assembly 46 transfers any excess lubricant from various nondrainable areas of the machine and returns same to the lubricant reservoir. The importance of the modular dispensing means of the invention toward the provision of an ideal lubrication is first, that it filters the lubricant, thus preventing dust, lint and foreign materials from entering into the system. Second, the provision of an accurately adjustable dispensing means coupled with a positive displacement pump assembly means assures that lubricant may be delivered to the various components of the machine in accurately metered amounts. In this manner, it is possible to optimize the antifrictional and heat dissipation characteristics of the lubricant. The provision of a pressure relief valve means in the present invention will assure a substantially constant lubricant pressure in the system throughout the speed range of the machine. The bypass valve means may further be used to optimize the flow rate through the dispensing means, thus, ensuring accurately measured amounts of lubricant to be delivered to the various areas of the machine. The embodiment of the invention show and described herein is to be considered merely as illustrative as the invention is susceptible to variation, modification and change within the spirit and broad scope of the appended claims.
This disclosure relates to a sewing machine lubrication system including positive displacement mechanisms adapted to transmit lubricant under pressure to the operating mechanisms of the machines and for transferring lubricant collected in non-drainable areas of the machine to the lubricant reservoir. Arranged in combination with the displacement mechanisms is a filtering/distribution assembly which serves to individually and selectively supply a relatively small, but sufficient quantity of lubricant to the operating mechanisms according to the requirements thereof. The present invention further provides a pressure relief valve assembly for selectively regulating the pressure in the lubrication system.
3
FIELD AND BACKGROUND OF THE INVENTION This invention relates to an improvement in the operation of strand production machines, such as ring spinning frames. During the operation of such machines, raw material is converted into continuous strands, such as yarns, and wound up on bobbins or tubes to form packages. The packages are designed to hold a predetermined nominal quantity (by weight or length) of the strand material. When a full package is formed on the machine, the full package is removed from the machine or "doffed" and replaced by an empty tube or bobbin. Although machines have been produced for automating the doffing function on certain strand production machines, it is more common for the doffing function to be carried out by an operator conventionally referred to as a "doffer". The conventional procedure for doffing the strand processing machines, which has been employed for many years, may be characterized as "cycle doffing". In cycle doffing, each doffer is assigned a group of machines, for example eight machines. The machines are doffed in cycles, with the doff cycle for each machine running a predetermined period of time. The doffer will doff each machine a certain number of times during each shift, depending upon the length of the doff cycle. Ideally, the doff cycles of the respective machines for which the doffer is responsible are staggered so that by the time the doffer has completed one machine, another machine is approaching readiness for doffing. However in actual practice, the doff cycles may not be evenly distributed, and there may thus result periods during which the doffer has idle time. Also, because of uneven distribution of the cycles, there may occur "short doffs" in which a machine is doffed before the packages are filled to the optimum desired amount. Also, under some circumstances, a machine may be ready for doffing while the doffer is still busy tending to another machine, which may result in producing a larger than standard package, which is undesirable, or if the machine is stopped, in nonproductive standing time while the machine awaits a doffer. It will be seen that the above circumstances result in inefficiences in the use of available manpower and in the utilization of the production equipment. ln an effort to overcome some of the disadvantages and limitations of the aforementioned cycle doffing procedure, it has been proposed to employ a procedure whereby the doffers are not permanently assigned to specified frames, but instead are assigned to a particular frame as the doffer becomes available and a frame becomes ready for doffing. Applicants are aware of at least a couple of instances in textile mills in which this approach has been implemented by using a type of mechanical linkage or switch on the frame, usually on the builder motion, for sensing when the doffing cycle is completed and signalling a computer which makes the frame assignment to the doffer. However, the capabilities of these systems were fairly restricted and did not involve significant frame monitoring functions or data gathering and reporting capabilities, nor did the systems actually exert control over the operation of the frames themselves. It is an object of the present invention to overcome the aforementioned disadvantages and deficiencies of the conventional "cycle doffing" approach, and to make optimum and most efficient use of available manpower and production equipment resources through the use of an improved "random doffing" approach in which available manpower is dispatched on a priority basis to the individual strand production machines which most require attention. It is a further object of the invention to provide a doff management system in which the production status of each machine is monitored and altered if needed, and changes in production status are recorded to permit producing various historical reports concerning the textile mill operation and its efficiency. SUMMARY OF THE INVENTION The doff management system of the present invention employs sensors on each strand processing machine for sensing various aspects of the production status, and a central processing unit or computer communicating with the sensors on the various machines and operating under program control to monitor and govern the operation of a number of functions and aspects of the operation of the textile mill. Among the functions which are provided by the present invention are (a) monitoring the strand production at each machine and whether the production has achieved a predetermined criteria required for doffing; (b) producing schedules of the machines which will be ready for doffing within a forthcoming time period; (c) handling assignment of available doffers to frames which are ready for doffing in accordance with predetermined doff priority criteria; (d) tracking the earnings of doffers paid on a per-doff basis or other basis and displaying the accumulated earnings to the doffer on demand; and (e) monitoring and recording various changes in the production status of the machines and generating current, historical and prospective reports concerning the textile mill operations. BRIEF DESCRIPTION OF THE DRAWINGS Additional features and functional capabilities of the doff management system of the present invention will become apparent from the detailed description and claims which follow, and from the accompanying drawings, in which FIG. 1 is a perspective view of a textile mill incorporating an installation of apparatus in accordance with the present invention; FIG. 2 is a schematic plan view of a textile mill similar to that of FIG. 1, illustrating the arrangement of a number of ring spinning machines in the mill; FIG. 3 is a fragmentary schematic perspective view of certain components of one of the ring spinning machines shown in FIG. 1; FIG. 4 is a schematic representation illustrating certain components of apparatus in accordance with the present invention and how they are operatively interconnected; FIG. 5 is a view illustrating both sides of a doffer card which a doffer may use in accordance with the present invention to receive an assignment of a spinning machine for doffing and, to obtain information concerning his earnings; and FIG. 6 is a schematic flow chart depicting the data processing functions in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION While the present invention will be described hereinafter with particular reference to the accompanying drawings, it is to be understood at the outset that persons skilled in the arts applicable to the present invention will be enabled by this disclosure to construct apparatus and to practice methods which embody the present invention and yet take forms which may differ from those here particularly described and shown. Accordingly, the description which follows is to be understood broadly as an enabling disclosure directed to persons skilled in the appropriate arts, and is not to be taken as being restrictive upon the scope of the present invention. While the present invention is contemplated as being useful in connection with various types of textile yarn processing machines, the invention is illustrated and described herein in connection with a plurality of ring spinning machines, certain of which are indicated generally at 10 in FIG. 1, arranged in a series of rows in a textile mill. One typical arrangement is schematically illustrated in FIG. 2, where the spinning frames 10 are arranged end to end in a series of rows, with aisles or alleys between adjacent rows to permit servicing of the machines by attendants. In a textile mill employing ring spinning machines of the type illustrated herein, the attendants normally include "spinners" who are responsible for maintaining control of the spinning frames, periodically patrolling each frame alley, replacing empty roving bobbins, and piecing up broken ends; and "doffers" who are responsible for removing or "doffing" the full yarn bobbins from a spinning frame, replacing the spindles with empty bobbins, and restarting the spinning frame. Each of the ring spinning machines includes elements for receiving raw material in the form of a fibrous strand known as roving, drawing or attenuating the roving, and twisting the attenuated roving to form yarn. The operating instrumentalities of a ring spinning machine are well known to persons skilled in the applicable textile arts, and are therefore not described in detail herein. In summary, as shown in FIG. 3, the elements include a drafting zone 12 where the strand material is drawn and attenuated, a front or delivery roll 14 where the attenuated yarn Y is delivered, intermediate guides 15 or "pigtails" through which the yarn passes, and rings 16 encircling spindles 17 and about which travelers move in twisting or spinning ends of yarn and winding them onto the bobbins. The rings 16 are mounted in ring rails 19 which move vertically relative to the spindles 17 as the yarn is wound thereon to build a yarn package 20. In commonly-owned and related U.S. Pat. Nos. 3,523,413; 4,194,349; 4,294,066; and 4,294,065 there is disclosed a system for monitoring certain operating conditions of the spinning frames in a textile mill, displaying information concerning the operating conditions at strategic locations within the mill, and utilizing the information to assist spinners in locating and piecing up ends down and to thereby improve the efficiency of operation of the machines. As described more fully in the aforementioned patents, and as shown schematically herein, one or more traveling units 22 (FIGS. 1 and 2) is arranged for traversing the textile machines along predetermined paths of travel defined by overhead rails 23 in order to monitor and detect the condition of the ends of yarn normally being formed, to determine whether any of the ends are broken, and upon detection of a broken end, to interrupt the feed of roving to the drafting zone. In addition, data concerning the ends down condition of the spinning machine is collected and transmitted to a central processing unit where the ends down information can be displayed or printed to facilitate more efficient operation of the machine and allocation of the spinners for piecing up the ends down. Also as described in aforementioned U.S. Pat. Nos. 4,194,349, 4,294,065, and 4,294,066, each spinning frame is equipped with certain sensors for signaling certain operating characteristics of the machines. Referring more particularly to the sensor means, and to FIG. 3, one sensor means takes the form of a suitable electrical device and associated components which together function as a rotation sensor means 24 for generating of electrical pulse signals at a frequency proportional to the revolutions of the delivery rolls 14 from which strand material issues. In the embodiment illustrated, a magnet 25 is connected to the delivery roll 14 so as to rotate therewith. The interconnection may be direct or indirect through gearing by which the rolls are driven. The magnetic proximity detector 25, such as a Hall effect device 26 which is responsive to variations in the magnetic field, is mounted adjacent to the roll 14 so as to sense each time the magnet passes by and for generating a train of electrical pulse signals. Persons skilled in the appropriate arts will recognize that other specific forms of rotation sensor means 24 may be employed. From the signal produced by the front roll sensor means 24, the number of revolutions of the front roll 14 can be determined, and hence it is possible to monitor the quantity of yarn produced at a given spindle. This information, coupled with data concerning the number of ends down and the number of spindles on each side of the frame, provides an indication of the amount of yarn produced on each side of the frame. Additionally, by comparing the cumulative number of revolutions of roll 14 during a given doff cycle and comparing this to a standard count for the number of revolutions in a complete doff cycle, it is possible to accurately determine at any time the particular status of a frame in its doff cycle. The pigtail or intermediate guides 15 along the length of a ring spinning machine 10 are mounted on a common mounting rod or bar 28 in order to permit a doffer to readily move all of the guides to a raised, inoperative position during doffing. Suitable means, shown in the form of mercury switch 29, is fixed to the common mounting bar 28 for movement with the intermediate guides and thereby serves as a guide position sensor means for generating an electrical signal upon the movement of the guides from the lowered operative position to the raised inoperative position. When a doffer begins the process of doffing a ring spinning machine and moves the intermediate guides to the raised inoperative position, this occurrence is detected by the sensor 29. While only a single device is shown in FIG. 3, a plurality of sensors 29 may be provided on any ring spinning machine having intermediate guides which are grouped into more than one grouping or area around the machine. Thus, a guide position signal would be generated upon movement of any group of intermediate guides to a position indicative of doffing occurring. Each spinning machine is equipped with a frame board means 41 (FIG. 3). In the embodiment shown, the frame board means 41 is electrically connected with the rotation sensor means 24, and the guide position sensor means 29. The frame board means 41 incorporates appropriate semiconductor logic circuit means (in forms known to persons skilled in the appropriate arts) for receiving from the sensors 24 and 29 electrical signals indicative of the rotation of the front roll 14 and the position of the intermediate guides 15. Signals regarding the guide position are, in essence, stored or recorded awaiting inquiry as explained more fully hereinafter. Signals indicative of rotation of the delivery rolls 14 are counted, with the numerical count being stored for inquiry as explained more fully hereinafter. The frame board includes a universal asynchronous receiver-transmitter (sometimes referred to as a UART) for communication as described more fully hereinafter. In addition, in accordance with the present invention each frame is equipped with a motor controller 36 associated with the main drive motor of the spinning frame (indicated at 37) for controlling the stopping or starting of the frame on certain conditions. The motor controller 36 is electrically connected to the frame board 41 for receiving signals transmitted from the central processing unit, when certain conditions have occurred which would require stopping of the frame, such as for example when the doff cycle has been completed and the frame is ready for doffing. In preparing a spinning frame for doffing, it is necessary to move the ring rail 19 to a retracted, inoperative position where it will be out of the way and free from obstruction when the doffer removes the full bobbins and replaces empty bobbins on the spindles. The lowering of the ring rails in preparation for doffing is commonly referred to in the art as "bearing down". This is commonly accomplished manually by the doffer when he reaches the machine, by actuating a lever or linkage provided for this purpose. However, in some instances spinning frames are equipped with "automatic bear down" devices which will automatically cause the ring rails to be lowered in preparation for doffing. Conventionally, the automatic bear down sequence is triggered mechanically through a linkage associated with the builder motion which controls reciprocation of the ring rail. In FIG. 3, the builder motion is broadly indicated at 40 and may include various mechanical linkages 42 and an associated actuator. In accordance with the present invention and as illustrated in FIG. 3, a bear down actuator device indicated at 43 may be provided in each frame connected to the builder motion 40. The bear down actuator device 43 is electrically connected to the frame board means 41 for receiving a signal from the central processor indicating the need for bearing down the ring rails. As illustrated in FIG. 4, the frame boards 41 for the respective spinning machines 10 communicate with a corresponding one of a plurality of circuit processor means 46. Each circuit processor means is preferably a microcomputer of a commercially available type, such as Intel system 8010. In a typical textile mill installation having a plurality of ring spinning machines, a plurality of circuit processors 46 are provided, each communicating with a corresponding plurality of frame boards 41 through the use of UARTS. Each circuit processor receives signals not only from the corresponding plurality of frame boards 41 but additionally from portions of the data system carried aboard the traveling units 22, as described more fully in the aforementioned related prior patents incorporated by reference into the present disclosure. The circuit processors receive from the frame boards 41 and traveling units 22 signals indicative of the ring rail positions, roll revolution count, ends down, and ends up. From such data, each circuit processor 46 may compute delivery roll speeds in revolutions per minute, time intervals relative to spinning machine operation, and totaled ends up and down. A plurality of circuit processor means 46 communicate with a single central or main processing unit 50. The central processor 50 functions primarily as a master for the entire processor system, with the plurality of circuit processors 46 and the plurality of frame boards 41 responding to the central processor 50. The central processor 50 carries out a number of functions, including those described in the aforementioned commonly-owned U.S. Pat. No. 4,194,349. As is illustrated in FIG. 4, the central processor receives from the plurality of circuit processors 46 signals indicative of certain changes in status of the spinning machine operation, delivery roll speeds, guide position signals, and ends down. The central processor also generates display signals to drive various visual displays, such as the CRT video devices 61 illustrated. In addition, in accordance with the present invention certain significant additional capabilities and functions are provided by the central processor 50 and certain associated sensors and actuators. In the preferred embodiment illustrated and described herein the central processor 50 takes the form of a commercially available microcomputer having multiprocessing capabilities and equipped with a large capacity non-volatile data storage device, such as a Winchester disk drive for example, for storing large quantities of data relating to the textile mill operations, as well as for storing systems and applications software. As schematically indicated in FIG. 4, the central processor operatively communicates with circuit processors 46, and in turn with frame boards 41 and traveling units 22 as earlier described. Additionally, the central processor is communicatively connected to video display devices such displays 61, at selected locations throughout the textile mill, a console unit 62, typically including a keyboard and video display, for controlling operations of the system, a printer 63, and a input/output device for use by the doffer, such as a magnetic or optical card reader 64 as illustrated. As is further schematically illustrated in FIG. 4, the central processor 50 includes a suitable commercially available operating system 71 as well as various applications programs 72 for carrying out the various functions and tasks of the monitoring system as described more fully hereinafter. Persons skilled in the appropriate arts are capable of selecting an appropriate commercially available operating systems, and for programming applications programs capable of performing the functions and tasks hereinafter described. Accordingly, it is neither necessary or desirable to include an extensive detailed description of these detailed aspects of applicant's invention. By way of example, one suitable operating system is the XENIX operating system, available from Microsoft Corp. and the applications programs may be written in a suitable programming language such as C, Pascal or Basic. The use of a standard operating system also makes it possible for the user to write his own programs employing any familiar programming language, in order to make use of the stored information in the data tables. An important and significant aspect of the invention is the provision of a data table 73 for storing significant information relating to the operations of the textile machines. Depending upon the storage capacity, historical data may be retained for as much as a year or longer. From this data, it is possible to generate current as well as historical reports relating to various aspects of the operations of the textile mill. To facilitate generation of such reports from the data tables, the central processing unit is provided with report generator means 74, in the form of computer programs capable of producing various standard frequently used reports, as well as user defined reports containing selected fields of information for specific purposes. Additionally, the central processing unit 50 provides the capability for other computer systems 80 to access the stored data in the data tables, via an RS 232 port or other suitable means. Thus it is possible for example for the mainframe computer of a textile mill to obtain access to the stored data in the data tables and to process this data for any desired purpose. FIG. 6 schematically illustrates various functions which are achieved by the system of the present invention. In summary, these functions include: (a) automated frame stop and bear down (b) frame doff scheduling (c) doffer assignment (d) doffer payroll (e) frame status monitoring and report generation. One important function of the system is to continuously monitor the yarn production at each machine, and to determine when the machine has produced a full bobbin of yarn, and to thereupon stop the machine and assign a doffer to doff the machine. Referring to FIG. 6, as indicated at 81, production of each spinning frame is monitored by the roll revolution sensor 24, previously described. Each machine has a preset doff quantity criteria representing the optimum of revolutions in a complete doff cycle. As indicated at 82 in FIG. 6, the current production of each machine is compared to the doff quantity criteria. When the number of roll revolutions on a frame reach the desired doff quantity criteria, information is generated indicating that the frame is ready for doffing. At this time if the frame is equipped with automatic bear down equipment, a command or instruction is directed to the bear down actuator 43 to bear down the ring rail 19 in preparation for doffing. Also at this time a command or instruction is directed to the motor controller 36 for that frame to stop the operation of the frame. This prevents overruns which could cause production of a yarn package larger than of optimum size, which may cause handling problems or in some instances damage the equipment or the yarn package. The fact that the frame is ready for doffing is also noted, and that frame is added to a priority list of frames which are awaiting doffing, indicated at 83 in FIG. 6. In the conventional operation of a textile mill, each doffer is assigned certain specified frames as his responsibility. Desirably, the doffer keeps these frames on a staggered doff schedule so that he can successively doff each respective frame. However, this approach often results in the doffer stopping the operation of a frame prior to its reaching full capacity, or in some instances allowing the frame to overrun and build an oversize yarn package. The present invention provides for the use of a random doffer assignment system whereby each available doffer is used where most needed for doffing those frames which are ready for doffing. This makes it possible to obtain most effective use of available manpower, to maximize bobbin weights, and to help reduce unproductive machine down, time so as to thereby increase the overall production efficiency of the mill. Additionally, the system can provide payroll calculations for doffers who are paid on a per-doff or other basis. When a doffer is available and ready to receive an assignment of a frame for doffing, the doffer makes an inquiry (84 in FIG. 6) at a doffer station conveniently located in the spinning room. In the embodiment illustrated, the assignment station is in form of a card reader 64, although it will be apparent that other means may be employed for accomplishing this function. Each doffer is assigned a personal card 79 having a unique identification thereon. (FIG. 5) The identification may comprise an optically readable bar code as illustrated or other suitable means such as magnetic coding or the like. When the doffer passes his card 79 through the reader 64, as shown in FIG. 1, a display 64a associated with the card reader 64 assigns to the doffer to the next available frame which is awaiting doffing, based upon a predetermined frame priority system (85 in FIG. 6). The central processor 50 maintains a priority list (83 in FIG. 6) of those frames which are available for doffing, with the priority being based upon preselected criteria which may be specified by the mill. For example, the criteria may involve the length of time that the frame has been idle and awaiting doffing, the particular style of yarn being produced on that frame, the location of the frame relative to the doffer making the request, or a combination of these or other criteria. Once a frame has been assigned to a doffer, this event is recorded in the data tables 73. When the doffer reaches the frame and begins doffing, as sensed by the guide position sensor 29, this event is also noted and recorded in the data table 73. Similarly, when the doff is completed and the frame is restarted, this event is also recorded. The system also keeps track of the number of doffs made by a doffer during a given shift or pay period, to thereby provide payroll calculations for each doffer. As indicated at 88 in FIG. 6, when a doff is completed, the doffer's payroll record is updated. As seen in FIG. 5, the reverse side of the doffer card 79 is labeled "earnings" and also bears a unique optically readable code. By passing the card through the reader 64 with the earnings side up, the doffer can make an inquiry 89 and request and obtain display 90 of his cumulative earnings at that time. Based upon the information which has been accumulated and recorded by the system and in the data tables 73, various kinds of reports can be obtained by the mill supervisor or other personnel. For example, since the system continually monitors the status of each frame in its doff cycle, a doff schedule report may be produced upon request, which provides a chronological listing of all frames which will be ready for doffing within a specified period of time. This allows the supervisor to identify peak doffing periods in sufficient time to take necessary action, such as by obtaining additional doffing help or by modifying doffing schedules. An example of a doff schedule report is reproduced below as Table I. If the supervisor wishes to modify doffing times in order to make more effective use of available manpower during peak doffing periods, the supervisor may, through the keyboard, specify an override criteria, such as an earlier doffing time or lower bobbin weight for selected frames. When the frame reaches that criteria, it will be stopped and a doffer will be assigned to the frame for doffing as though a full doff cycle had been completed. This ability to look ahead at the doffing schedule and to take corrective action by modifying doffing times enables the supervisor to maximize efficiency and productivity. An other important function of the present invention is to continuously monitor the operating status of each frame in the spinning mill (86 in FIG. 6). Each time a change in the operating status of a frame occurs, this event is noted (87) and recorded in the data table 73. Examples of changes in the production status include (1) when a frame is started and begins production, (2) when a frame is stopped, (3) when a doffer is assigned to the frame for doffing, (4) when the doffer actually begins doffing, (5) when the doffing is completed and the frame is restarted, and (6) when a frame is taken out of production such as for servicing or due to over capacity. From the data table containing this information it is possible to generate various reports, including information such as the total running time of a given frame or group of frames, total production, percent efficiency in production, time that the machine is awaiting assignment of a doffer, time spent during doffing, number of doffs, etc. For example, a doff track report similar to that illustrated in Table II below, may be produced which gives a chronological listing of the exact times that frames were doffed over some specified period of time. Frame track reports such as that illustrated in Table III are also available for listing for any particular frame, times that any frame condition change occurred; i.e. doffing, standing, frame temporarily removed from mill operation, etc. It will be readily appreciated that from the information available in the data table, and the information being currently obtained by the system, various other historical, current, and prospective reports can be produced. TABLE I__________________________________________________________________________DOFF SCHEDULE REPORTFrom Thu Aug 15 11:15 to Thu Aug 25 13:00 1985Frame Actual Standard Standard Current Calculated Modified % ofNo. Speed Speed Revs Revs Doff Time Doff Time Standard__________________________________________________________________________13 161 160 62131 62008 11:27 100%56 148 160 77664 74696 11:47 100% 1 159 160 62131 58928 11:47 100%89 159 160 77664 73128 11:55 100%22 161 160 62131 55976 12:05 100%57 163 160 77664 69520 12:16 100%70 160 160 77664 69472 12:18 100%33 156 160 77664 67240 12:33 100% 4 158 160 62131 50472 12:40 100%74 159 160 77664 65360 12:44 100% 7 161 160 62131 49680 12:44 100%61 159 160 77664 63880 12:53 100%__________________________________________________________________________ TABLE II__________________________________________________________________________DOFF TRACK REPORTFor Wed Aug 7 1985 from 5:45 to 6:40 E.D. Doffer Doffer at Style Total Minutes TotalTime Frm Stat'n Number Id Doff # Assign Wait Doff lbs.__________________________________________________________________________5:54 90 E 105 JOE 6 1 9 0 5 68.06:01 49 H 108 ED 2 1 0 26 6 83.76:06 24 G 107 BOB 0 2 0 5 7 69.26:07 3 F 106 JIM 12 2 0 1 7 71.46:15 53 H 108 ED 5 1 12 0 7 89.76:19 6 F 106 JIM 2 2 0 2 5 64.06:22 57 G 107 BOB 0 1 0 0 11 73.56:32 67 E 105 JOE 1 1 0 0 6 72.16:36 9 F 106 JIM 17 2 0 0 8 64.56:39 59 G 107 BOB 5 1 5 1 10 75.4__________________________________________________________________________ TABLE III______________________________________FRAME TRACK REPORTFrame 35For Fri Aug 9 1985 from 9:30 to 12:00Style = 1 31/1 Cotton 2" Ring Lbs./Bob = 250 Revs = 77664Speed = 165 Spinner I = C, Spinner C = C, Doff Station = LTime Condition Speed EDI EDC Time Since Change______________________________________10:30SPG 0:18 158 0 410:48OVR 0:00 158 0 1 9311:00OVR 0:12 158 0 111:04WTA 0:00 158 0 0 1611:06DOF 0:00 158 0 0 211:12SPG 8:06 158 0 0 611:30SPG 7:48 159 1 212:00SPG 7:18 160 2 2______________________________________
The doff management system of the present invention employs a central computer unit communicating with each yarn processing machine in a textile mill and operating under program control for monitoring and governing the operation of various functions and aspects of the mill operation. The system monitors strand production at each machine and whether the production has reached a predetermined criteria required for doffing; producing schedules of the machines which will be ready for doffing within a forthcoming time period; with the capability of altering the doffing schedules necessary to distribute workload; handling assignment of available doffers to frames which are ready for doffing; tracking earnings of doffers; and monitoring and recording various changes in the production status of the machines and generating current, historical, and prospective reports concerning the textile mill operations.
3
This application is a continuation-in-part of application Ser. No. 143,645 filed Jan. 13, 1988 now abandoned. This invention relates to the hydroisomerisation of olefinic hydrocarbons to paraffinic hydrocarbons by the use of a high-silica zeolite or zeolite-like catalyst containing a metallic component of the platinum group. It is known to those skilled in the art that: olefinic hydrocarbons can be hydrogenated to paraffinic hydrocarbons by contact with a catalyst of the platinum group, such as platinum itself or palladium, in the presence of hydrogen. olefinic hydrocarbons can be isomerised by contact with acid catalysts. It is likewise known that the isomerization and hydrogenation processes can be combined as a hydroisomerization process, whereby an olefinic hydrocarbon and hydrogen are contacted together with a catalyst, with the object and effect of converting an olefinic hydrocarbon with a less branched skeleton to a paraffinic hydrocarbon with a more branched skeleton. Such hydroisomerization processes are disclosed in U.S Pat. Nos. 3,749,752 and 3,796,766 and in European Patent No. 49,803. Hydroisomerization catalysts of the prior art have two components; first an acidic component, such as alumina or silica-alumina whether alone or with inclusion of a zeolite; and second a metal most commonly of the platinum group. The first component serves as an acid and also as a support for the metal of the platinum group. In general, where the first component contains large amounts of alumina or silica-alumina then it may be expected that the metal of the platinum group will be supported upon the surface of the alumina or silica-alumina, rather than within the molecular channels and cavities of the zeolite. Thus, the hydrogenation step effected by the metal will be divorced from any shape-selectivity which the zeolite might impose. Pollitzer, in U.S. Pat. No. 3,542,671 teaches the hydroisomerisation of light olefins to a product rich in branched-chain paraffins, over a hydroisomerisation catalyst having a noble metal supported by a zeolite and a larger amount of a conventional support such as silica-alumina or fluorided alumina. Likewise, Wilhelm, in U.S. Pat. No. 3,723,554 teaches the use of platinum supported on alumina to hyroisomerise a less branched alkane to a more highly branched alkane. Thermodynamic equilibrium between the isomeric alkanes of any carbon number at temperatures in the 150°-250° C. range of present concern favours the branched chain alkanes over the straight chain alkanes. The following table gives the theoretical composition of an equilibrium mixture of hexane isomers at 223° C. (Source: CSIRO Thermochemistry System Program Package, CSIRO, Australia). TABLE______________________________________Equilibrium between hexane isomers at 223° C.______________________________________n-hexane 14%2-methylpentane 30%3-methylpentane 14%2,2-dimethylbutane 31%2,3-dimethylbutane 11%______________________________________ Thus, the prior art on hydroisomerisation teaches exclusively how a paraffin or mixture of paraffins may be isomerised leading to a composition more nearly characteristic of thermodynamic equilibrium and how an olefin or mixture of olefins may be hydrogenated to a mixture of paraffins more nearly characteristic of thermodynamic equilibrium than the composition that would have been obtained by simple hydrogenation without skeletal rearrangement. It is further known that shape-selective catalysts prepared by introducing a metal of Group VIII of the Periodic Table, such as platinum, palladium, ruthenium, rhodium, osmium, iridium or nickel, into a high-silica zeolite such as ZSM-5 zeolite, can be used to hydrogenate less highly substituted or branched olefins selectively in the presence of more highly substituted or branched olefins. Dessau, in J. Catalysis Vol. 77 (1982) pp. 304 and Vol 89 (1985) pp 520, teaches the selective hydrogenation of less branched olefins in the presence of more highly branched olefins over platinum/ZSM-5 catalysts at temperatures up to 275° C. He also teaches the isomerisation of olefins by migration of the double bond within the carbon skeleton of an olefin, but not by skeletal isomerisation, over the proton form of ZSM-5 zeolite at temperatures up to 200° C.; thus hexene-1 is isomerised to hexene-2. It has hitherto been unknown that the catalyst and process conditions for hydroisomerisation can be so selected that an olefin with a more branched skeleton can be hydroisomerised to a mixture of paraffins in which paraffins of less branched skeletons are abundant. The abundance of the less branched paraffins is not limited by thermodynamic equilibrium. Thus, a branched-chain hexene may give more than 40% n-hexane at a reaction temperature of about 223° C. BRIEF SUMMARY OF THE INVENTION It is an object of the present invention to provide a process whereby olefinic feedstocks may be hydroisomerised to paraffinic feedstocks and specific catalysts therefor. The process is characterised by the paraffinic products having, on average, less highly branched carbon skeletons than the olefins from which they are derived. By way of example, 2-methylpent-1-ene or 3,3-dimethylbut-1-ene may be hydroisomerised to a product containing large amounts of n-hexane. Accordingly, the invention provides a single-stage process for the shape-selective hydroisomerization of a branched olefin of at least 4 carbon atoms to produce a less branched paraffin product, said process comprising contacting said olefin and a hydrogen-containing gas with a zeolite or zeolite-like catalyst containing at least one metal of Group VIII and in which a major portion of said at least one of these metals is supported within the molecular channels and cavities of the said catalyst, said process being conducted under conditions such that hydroisomerization predominates over both simple hydrogenation and cracking. The term "supported" means both exchanged metals and metals occluded within the cavities of the zeolite. The olefin reactant may be a gaseous or liquid hydrocarbon of 4 or more carbon atoms and in particular, one or more components of a mixture of hydrocarbons boiling in the kerosine and distillate ranges (typically 196°-317° C.). The catalyst may be ZSM-5 zeolite which may contain other metals in addition to the metals of the platinum group, e.g. boron, gallium and iron, with or without aluminium. DETAILED DESCRIPTION OF THE INVENTION The invention utilizes zeolites of high silica content, which have cation exchange properties and display shape-selectivity in their catalytic and sorptive properties. The term zeolite is conventionally applied to aluminosilicates, of natural or synthetic origin, in which the aluminosilicate framework is anionic and contains channels and interconnecting voids, which contain cations and water molecules, the cations being exchangeable and the water molecules being in many cases removeable without loss of the zeolite structure, so allowing the sorption of other molecules such as, for example, olefins and alkanes. However, elements other than silicon, aluminium and oxygen can be introduced into the framework of a zeolite, either at the time when the zeolite is prepared or subsequently. Accordingly, the process of the invention is not limited to the use of aluminosilicates, but includes materials of zeolite-like composition and properties containing such elements as boron, gallium, and iron, whether with or without aluminium, provided that such materials are highly siliceous and show cation-exchange and shape-selective properties like the aluminosilicate zeolites to which the process of the invention particularly applies. In specifying zeolites and zeolite-like catalysts and compositions, we follow the usage recommended by Professor Meier in his plenary lecture "Zeolites and Zeolite-like Materials" delivered to the 7th International Zeolite Conference in Tokyo, 1986 and published in `New Developments in Zeolite Science and Technology`, editors Y. Murakami, A. Iijima and J. W. Ward, Elsevier, 1986, p. 13 et seq., which are incorporated herein by reference. Professor Meier states (loc. cit. page 13): `extensive isomorphous substitution of framework atoms and numerous structural analogues of aluminosilicate zeolites, as well as other recent developments in zeolite structural chemistry, make it seem logical not to impose artificial limits to this class of porous crystalline materials`. In particular, we include within the class of zeolite-like materials to which the present invention applies those materials related to the appropriate aluminosilicate zeolites by isomorphous substitution in the anionic skeleton of the structure. Examples of the use of zeolite-like materials isomorphously related to ZSM-5 zeolite are taught in examples 26 and 27 below. The invention may be applied to zeolites showing shape-selectivity as defined by Csicsery (loc. cit. below) which zeolites include zeolites having the skeletal structure of mordenite and offretite, and may also be applied to ferrierite, ZSM-5, ZSM-11, ZSM-12 zeolites. The method of the invention applies particularly to highly siliceous zeolites. Highly siliceous can be defined as having an SiO 2 content greater than 80 wt %. Of particular interest are zeolites of the mordenite types and the pentasil zeolites, including ZSM-5 and ZSM-11. The zeolites are characterised by free aperture sizes governed by rings of 12 or 10 T atoms respectively, where T is an atom of an element such as silicon or aluminium, or such other element as boron, gallium or iron, and where the T atoms are joined together through oxygen atoms. The term "free aperture" follows the usage of D. W. Breck, Zeolite Molecular Sieves, Wiley, 1974. The lower limit to free aperture size of the zeolite is set by the ability of the reactant molecule to enter the zeolite voids. Thus, the zeolite is required to admit a branched olefin which is to be isomerised and hydrogenated to a less branched paraffin. The lower limit may be circumvented advantageously to some extent by use of zeolite having particles of particularly high surface area, which property may be distinguished by transmission electron microscopy and is not to be confused in the case of a porous material such as a zeolite with surface area measured by the simple BET method. Thus, ZSM-5 zeolite may be prepared with various morphologies depending on the method of preparation and the morphologies may be distinguished by transmission electron microscopy. Many of the morphologies are characterized by well defined crystal faces with dimensions of the order of 0.1 micron or greater. Such morphologies include picket-end laths with a longest-dimension in the range 0.1 to 5 microns, spheral aggregates of laths radiating from a centre, and bulky intergrown crystals having lengths, diameters and the thicknesses of the order of 0.5 micron or greater. By contrast the zeolite particles of particularly high surface area, which hereinafter we refer to as "high-area" zeolite, comprise particles having overall dimension of the order of 0.1 micron. However, such a particle comprises many platelets of very much smaller dimension. The platelets are joined together, but the mass of platelets comprising the particle is penetrated by voids with dimensions comparable with those of the platelets. Conversely, the upper limit to free aperture size will be set by the need to reduce isomerisation to more highly branched isomers. The constraint will be to allow entry of the pertinent branched olefin but not ready egress of more highly branched paraffins. Thus, the zeolite of choice may vary according to the degree of branching in the olefin feed. The property of shape-selectivity has been described by Csicsery, in "Zeolite Chemistry and Catalysis", ACS Monograph 171 (1976) pp 680 (edited by Rabo) and by Weisz in "Proceedings of the 7th International Congress of Catalysis", Tokyo (1980) (Vol.A, p. 3). The method of the invention is applicable to zeolites displaying the property of shape-selectivity. The process of the invention requires that one or more metals of Group VIII be incorporated into the zeolite or zeolite component. Such metals may be introduced prior to or during zeolite synthesis or subsequent to synthesis. In particular, the process of the invention requires that the metal or metals be so introduced that much of the metal content is within the channels and cavities of the zeolite structure. In a preferred method of preparing the catalyst for the process of the invention, the metal or metals are introduced into the zeolite, whether alone or compounded with silica or alumina or another oxide or clay, subsequent to the synthesis of the zeolite. Such introduction may be effected by various means, including impregnation with an aqueous or non-aqueous solution of one or more compounds of these metals. In a preferred method of catalyst preparation where the zeolite is free of binders which strongly sorb the impregnating compound, the zeolite is impregnated by an aqueous solution of a platinum salt, such as chloroplatinic acid. In another particularly preferred method, advantage is taken of the cation exchange property of the zeolite and the zeolite undergoes cation exchange with an aqueous solution of a tetrammineplatinum salt. All metals of Group VIII of the Periodic Table may be used but the metals of the platinum group and nickel are preferred. The platinum group comprises platinum, palladium, ruthenium, rhodium, osmium and iridium. These metals may be used singly or in combination with each other or with other metals such as zinc, iron, gallium. Of the metals of the platinum group, platinum itself is particularly preferred. The content of metals of the platinum group in the zeolite catalyst is preferably in the range of 0.05 to 5 wt %, preferably 0.1 to 3 %wt, and in the particularly preferred case where platinum alone is used, the preferred platinum content is 0.2 to 1.5 wt %. The preparation of metal loaded zeolites is described in chapters 10 and 12 of "Zeolite Chemistry and Catalysis" ACS Monograph 171, ed. J. A. Rabo. In the present invention, it is necessary that the metals of the platinum group introduced into the zeolite-like catalyst be reduced, and that they be so obtained and retained in such a reduced form in a high state of dispersion by methods familiar to those skilled in the art. Reduction may be achieved by treatment with hydrogen gas, either alone or admixed with inert gases or reactive gases, including the vapour of the olefinic feed utilized in the process of the invention, either in situ or prior to the practice of the process of the invention. Reduction may also be achieved by the use of a reducing agent other than hydrogen gas, such as, for example, hydrazine hydrate. It is an important characteristic of the process of the invention that the catalyst utilized is bifunctional, combining the hydrogenation function of metals of the platinum group with acidic properties of the zeolite itself. Such acidic properties are conferred by the presence of cations of appropriate type in appropriate quantities. More specifically, the acidic properties are conferred by the presence of protons (hydrogen cations) and multivalent cations, such as, for example, Zn 2+ , either singly or in combination with each other, in such amounts as to balance the negative charge of the zeolite, either totally or in part. Such protons and/or multivalent cations may be accompanied by univalent cations, such as alkali metal cations, most commonly sodium or potassium, which do not themselves effectively confer the desired acidity. A hydrogen cation may be introduced by treatment with mineral or other acid or by decomposition of the ammonium form or a tetraalkylammonium form or some other organoammonium form of the zeolite. Reduction of noble metal compounds to the metals themselves also serves to confer acidity. Thus, when the tetrammineplatinum ion is exchanged into a zeolite, subsequent decomposition and reduction yields platinum metal and protons. The process of the invention provides for the first time the shape-selective hydroisomerisation of an olefin with a more highly branched skeleton to paraffins with less highly branched skeletons. The departure of the process from the prior art lies in the use of a zeolite or zeolite-like component capable of shape-selectivity, either alone or in combination with the metal of the platinum group, combined with the metal or metals of the platinum group as a second component, the second component being introduced in such a manner as to be largely supported within the molecular channels and cavities of the zeolite, further combined with a choice of hydroisomerisation conditions, particularly of temperature, such that the hydroisomerisation predominates over both simple hydrogenation and cracking. The process of the invention cannot be applied to paraffins, so as to isomerise a more branched paraffin in counter-thermodynamic manner to less highly branched paraffins. It is a characteristic of the process that a temperature be selected for the process less than the temperature at which the paraffin products undergo hydroisomerisation over the catalyst applied to the process. The process of the invention may be understood (without being bound by any theory) in the following terms. The catalyst is bifunctional. The zeolite component serves to isomerise the olefinic reactant, both by shift of the double bond and more importantly by skeletal rearrangement. The platinum group metal component serves to hydrogenate the double bond to give a paraffin. Such hydrogenation is not substantially shape-selective if the metal is supported in the conventional manner upon the external surface of a particle of a support, such as alumina. However, when the metal is supported within the molecular channels and cavities of a zeolite, the olefin and hydrogen have to combine at the surface of the metal within the confines of the zeolite, in which circumstance it may be understood that the olefins with less branched skeletons undergo hydrogenation more readily, thereby being converted to paraffins with less branched skeletons, whereas the olefins with more branched skeletons are more likely to undergo isomerisation before hydrogenation. The shape-selectivity is not imposed by the zeolite alone, but by the platinum group metal particles within the zeolite, for which reason it is important that the platinum group metals be dispersed mainly within the channels and cavities of the zeolite. For this reason, zeolites having larger pore dimensions, for example, mordenite which has channels bounded by rings of 12 T atoms, may be applied. It is not essential that the isomerisation be confined to the channels and cavities of the zeolite. Where the reactant olefin can enter the zeolite channels freely, no advantage will obtain to isomerisation at the external surface of the zeolite particle. However, where the olefin is so highly branched as to impede free sorption into the channels, the first stages of isomerisation may need to occur at the external surface of the zeolite. Thus, advantage may obtain from the use of zeolite particles of small size and thus of high external surface area. The olefinic feedstock utilized in the invention may be a single olefin or a mixture of olefins, whether alone or in combination with other organic materials. The distinctive feature of the olefins used is that they mainly have branched skeletons. Such skeletons may be singly branched, in which case the present invention serves to lower the amount of hydrocarbons with singly branched skeletons and to increase the amount of hydrocarbons with unbranched skeletons. If the olefin skeletons are multiply branched, the invention serves to decrease the amount of hydrocarbons having multiply branched skeletons and increase the amount of hydrocarbons having singly branched skeletons and unbranched skeletons. In particular, the feedstock may comprise higher olefins obtained by acid-catalysed oligomerisation of light olefins, such as propene. Such oligomers commonly have a highly branched structure, which is advantageous for oligomers boiling in the gasoline range (up to 196° C.), but disadvantageous in higher boiling oligomers which have thereby poor cetane index or number. By the process of this invention, such higher boiling oligomers (boiling point 196° C.) can be upgraded into more useful transport fuelstock, in that reducing the degree of branching by the process of the invention thereby improves the cetane number of hydrocarbons. Thus, hydroisomerisation of 2-methylpentene-1 by the present invention gives a product containing n-hexane as well as 2-methylpentane and 3-methylpentane, whilst hydroisomerisation of 3,3-dimethylbutene-1 gives a product containing n-hexane, 2-methylpentane and 3-methylpentane, as well as 2,2-dimethylbutane and 2,3-dimethylbutane. The olefin-containing feed may be supplied to the catalyst at a weight hourly space velocity (WHSV) in the range 0.1 to 100 hr -1 , preferably 0.5 to 20 hr -1 , and may be delivered either in the vapour or liquid phase and may contact the catalyst either in the liquid or vapour phase. Hydrogen is co-fed to the catalyst in a H 2 /olefin mole ratio of preferably 0.5 to 100, more preferably 1 to 20, and most preferably 2 to 10. The partial pressure of hydrogen may be in the range 0.1 to 100 bar, preferably 0.5 to 30 bar. The hydrogen gas may be co-fed with only the olefinic feedstock or may be diluted with a non-oxidising gas such as nitrogen. Successful practice of the invention requires that the temperature at which the feed contacts the catalyst be carefully chosen. If too low a temperature is employed, isomerisation does not occur, and hydrogenation proceeds to give a paraffin with the same carbon skeleton as the starting olefin. Thus, 2-methylpentene-1 gives 2-methylpentane. If too high a temperature is employed, skeletal isomerisation is accompanied by the extensive occurrence of cracking reactions which convert the olefin to hydrocarbons of lower molecular weight. Under some conditions, use of an over-high temperature may also result in such undesirable side-reactions as the formation of cycloalkanes and aromatics. At a suitable chosen temperature, the value of which is dependent upon the choice of catalyst and the process conditions other than temperature, hydroisomerisation occurs with relatively little complication due to extensive occurrence of side-reactions. The chosen temperature will generally be in the range 150°-350° C., and for preferred catalysts and process conditions generally is in the narrower range of 180°-280° C. The present invention may be more clearly understood by means of the following examples, which illustrate various aspects of the invention together with comparative material. EXAMPLE 1 A mixture of 186 g silica sol ("Snowtex", 40 wt % SiO 2 ), 60 g tetrapropylammonium bromide and 100 g water was blended rapidly with a solution of 10 g sodium hydroxide and 2.5 g sodium aluminate in 100 g water. The resulting gel was transferred to a pressure vessel and heated in the closed vessel at 100° C. for 6 days then at 175° C. for 2 days. The crystalline slurry of ZSM-5 zeolite so formed was filtered, washed with water, dried at 100° C., calcined at 500° C. for 16 h., then treated with excess of 0.3 molar hydrochloric acid at 100° C. to give the proton form of the zeolite, having a aluminium content of 0.93 wt % and a sodium content of 0.01 wt % (balance SiO 2 and residual moisture). Morphologically the zeolite comprises agglomerates (200m diameter) of small platelets, which we refer to as "high-area" zeolite. EXAMPLE 2 The proton form of ZSM-5 zeolite prepared as in example 1 (2.5 g) was admixed with 0.125 of tetrammineplatinum dichloride in 2 g water. The pH fell below 1 immediately. After 24 h, the platinum-loaded zeolite was filtered, washed with water, and dried at 110° C. The platinum content was 2.05 wt %. EXAMPLE 3 The platinum-loaded zeolite of example 2 was pelleted, ground and sieved to 60-80 mesh size. 0.25 g of the material was then packed into a quartz tube and treated in a stream of flowing oxygen (20 cc/min) by heating first to 150° C. at a heating rate of 5° C./min. then at 150° C. for 1 h., then heating from 150° C. to 300° C. at a heating rate of 0.5° C./min, and finally heating at 300° C. for 1 h. The catalyst so treated was cooled to room temperature, purged by nitrogen, then heated to 250° C. in hydrogen at a heating rate of 5° C./min to effect reduction. EXAMPLE 4 0.10 g of the reduced platinum-loaded catalyst of Example 3 was packed into a tubular, atmospheric pressure microreactor, and was fed with 2-methylpentene-1 liquid (0.25 cc/h.) and hydrogen gas (300 cc/hr) at temperatures of 150°, 200° and 250° C. The reaction product was analysed by on-line gas chromatography and its hydrocarbon content was found to have the composition shown in Table 1. TABLE 1______________________________________ Reaction temperature 150° C. 200° C. 250° C. Yield (C %)______________________________________Products:C.sub.1/2 hydrocarbons 0 0 0C.sub.3 hydrocarbons 0 1 2C.sub.4 hydrocarbons 0 2 2C.sub.5 hydrocarbons 0 2 2Total C.sub.6 hydrocarbons 100 93 93The C.sub.6 hydrocarbons comprised:2-methylpentane 97 53 413-methylpentane 3 17 152,2-dimethylbutane 0 0 02,3-dimethylbutane 0 0 0n-hexane 0 23 36olefins 0 0 0______________________________________ EXAMPLE 5 The experiment of Example 4 was repeated but substituting 2-methylpentane for 2-methylpentene-1 as the liquid feed. The hydrocarbon products were almost exclusively unchanged 2-methylpentane at 150°, 200° and 250° C. EXAMPLE 6 The experiment of Example 4 was repeated but using 3,3-dimethylbutene-1 (0.25 cc/h.) as the liquid feed instead of 2-methylpentene-1. The composition of the hydrocarbon products, determined by on-line and off-line gas chromatography, is shown in Table 2. TABLE 2______________________________________ Reaction temperature 150° C. 200° C. 250° C. Yield (C %)______________________________________Products:C.sub.1/2 hydrocarbons 0 0 1C.sub.3 hydrocarbons 0 0 3C.sub.4 hydrocarbons 0 1 2C.sub.5 hydrocarbons 2 2 3Total C.sub.6 hydrocarbons 98 96 91The C.sub.6 hydrocarbons comprised:2-methylpentane 12 45 423-methylpentane 4 11 202,2-dimethylbutane 25 6 22,3-dimethylbutane 53 7 1n-hexane 3 27 26olefins 0 0 0______________________________________ EXAMPLE 7 2,6-dimethylheptene-3 liquid (0.25 cc/h.) and hydrogen gas (300 cc/h.) were fed to 0.10 g of the catalyst of example 3 at 200° C. The composition off the hydrocarbon product was determined by on-line gas chromatography and off-line gas chromatography/mass spectrometry. 20C % of the product consisted of cracked products, mainly C 3 -C 6 alkanes. 79C % was recovered as C 9 alkanes, namely 5C % n-nonane, 17C % methyloctanes (mainly the 2-isomer), and 56C % doubly branched nonanes (mainly 2,6-dimethylheptane). EXAMPLE 8 The experiment of example 7 was repeated (again at 200° C.) using as liquid feed olefinic propylene-polymer gasoline, and the following composition of the hydrocarbon products was determined as in Example 7, with attention being paid to the C 9 hydrocarbons, which are the most abundant constituents of the polymer gasoline. The composition is compared with the product of conventional hydrogenation of the polymer gasoline over palladium-on-charcoal catalyst at room temperature, which is shown in parentheses. 51C % of the product comprised C 9 hydrocarbons (59C % over Pd/C). 6C % was n-nonane (less than 1C % over Pd/C), 14% comprised methyloctanes (7C % over Pd/C), and 31C % had a doubly or triply branched skeleton (51C % over Pd/C). EXAMPLES 9-12 The following examples show that mordenite zeolites can be used, and further show that a zeolite may be modified by treatments other than ion-exchange, and additional to introduction of the metal of the platinum group, particularly by treating with a silylating agent, which is thought to improve the stability of the metal component towards migration and sintering. EXAMPLE 9 Sodium mordenite (Norton Zeolon 100Na) of 40 -60 mesh size was heated to 400° C. in a stream of argon, then heated to 180° C. in a stream of argon saturated with trimethylchlorosilane at 0° C., then again heated in pure argon at 400° C. for 1 hour. The mordenite so treated (1.0 g) was finely ground with platinum dichloride (0.03 g) then packed into a quartz tube and heated to 400° C. in a stream of chlorine/argon gas (1/1, v/v) at 400° C. till all sublimation of platinum compounds from the sample ceased. The sample was then cooled to 250° C. in situ and purged first by nitrogen then by hydrogen. The sample, still in situ, was finally heated to 400° C. for 16 hours in hydrogen, and was then removed from the quartz tube and pressed into a disc, which was then broken and sieved to 60-100 mesh size. EXAMPLE 10 The sodium form of the platinum-loaded, silanized mordenite, prepared as in example 9, was converted to the hydrogen form by placing in a short glass chromatography tube and eluting with 0.3 molar aqueous hydrochloric acid until the eluate was completely free of sodium ions. The catalyst so obtained was dried in an oven at 120° C. in air. EXAMPLE 11 The hydrogen form of platinum/silanized mordenite prepared as in example 10 (50 mg) was tested as a hydroisomerisation catalyst at 150°, 200° and 250° C. by feeding to it hydrogen gas (4 cc/min) saturated with 2-methylpentene-1 at 0° C. The compositions of the hydrocarbon products, determined by gas chromatography, are shown in Table 3. TABLE 3______________________________________ TemperatureProduct distribution (C %): 150° C. 200° C. 250° C.______________________________________C2-C5 hydrocarbons 1 10 252-methylpentane 83 31 223-methylpentane 12 17 13n-hexane 4 36 38______________________________________ EXAMPLE 12 The experiment of example 11 was repeated using 3,3-dimethylbutene-1 instead of 2-methylpentene-1. The product obtained at a reaction temperature of 150° C. comprised: 2C % C3-C5 hydrocarbons, 25C % 2,2-dimethylbutane, 66C % 2,3-dimethylbutane +2-methylpentane, 4C % 3-methylpentane, and 10C % n-hexane. EXAMPLE 13 This example collects together several experiments using metals of the invention other than platinum, which are used in combination with ZSM-5 zeolite. The example illustrates the usefulness of metals of Group VIII other than platinum for the process of the invention. TABLE 4__________________________________________________________________________ HYDROCARBON HYDROCARBON PRODUCTS AT 200° C. PRODUCTS AT 250° C. METAL FOOT- TOTAL TOTALEXPT. NO. CONCENTRATION FEED NOTES <C.sub.6 n-Hexane C.sub.6 >C.sub.6 <C.sub.6 n-Hexane C.sub.6 >C.sub.6__________________________________________________________________________TMH-E27 1.5 wt % Pd 2-MeP = 1 0.6 1.0 99.5 -- 16.9 12.6 80.0 3.5 " 2 0.2 1.1 99.8 -- 11.0 10.8 86.9 2.3 " 3 1.1 2.9 94.0* 4.8 17.8 15.1 64.2* 18.1TMH-E28 0.63 wt % Pd 2-MeP = 1 0.2 1.2 99.7 -- 20.4 25.4 74.4 5.3 " 4 0.4 2.5 99.5 -- 34.6 15.7 55.0 10.6TMH-E29 2.09 wt % Pd 2-MeP = 1 -- 0.2 100.0 -- 0.1 2.5 99.8 -- " 5 15.7 14.8 72.5 11.8 57.2 18.4 31.2 11.8 " 6 0.2 0.3 99.7 -- 0.9 4.1 99.0 0.3THM-E30 2.29 wt % Ru 2-MeP = 7 3.1 10.0 81.0* 15.9 27.9 9.1 46.9* 25.2 " 8 1.6 5.3 87.4* 11.0 -- -- -- --TMH-E31 0.65 wt % Ir 2-MeP = 7 10.3 10.6 84.6 5.1 39.7 11.7 49.3 10.8 3,3-Me2B = 3.1 2.9 97.0 0.2 41.8 9.5 48.8 9.4 2-MeP = 9 3.6 7.1 93.9 2.4 -- -- -- --TMH-E32 1.2 wt % Rh 2-MeP = 7 4.3 11.5 94.7 1.0 52.3 10.9 38.0 9.8 3,3-Me2B = 1.6 2.4 98.7 -- 48.6 8.6 44.8 6.5TMH-E33 0.79 wt % Ni 2-MeP = 7 2.0 3.5 88.2* 9.4 17.1 3.2 60.9* 22.1__________________________________________________________________________ FOOTNOTES: FEED 2MeP = represents 2methylpentene-1,3,3-Me2B = represents 3,3dimethylbutene-1. 1 CATALYST TESTED PRIOR TO CONDITIONING 2 CATALYST CONDITIONED AT 150° C. 5 cc/min H2 OVERNIGHT BEFORE RETESTING 3 CATALYST CONDITIONED AT 350° C. 5 cc/min H2 OVERNIGHT BEFORE RETESTING 4 CATALYST CONDITIONED AT 150° C. 5 cc/min H2 2.5 DAYS BEFORE RETESTING 5 CATALYST RETESTED AFTER FURTHER OXIDATION/REDUCTION 6 FRESH CATALYST CONDITIONED (CONVENTIONAL MANNER) PRIOR TO TESTING 7 CATALYST CONDITIONED (CONVENTIONAL MANNER) PRIOR TO TESTING 8 CATALYST FURTHER REDUCED AT 400° C. 5 cc/min H2 BEFORE RETESTING 9 2METHYLPENTENE-1 REPEAT AT 200° C. NO ADDITIONAL CATALYST TREATMENT BETWEEN EXPERIMENTS *DENOTES SIGNIFICANT OLEFINS REMAINING IN PRODUCT EXAMPLES 14-17 Teach the significance of variation in the platinum content of ZSM-5 catalyst. EXAMPLE 14 The experiment of example 4 was repeated but using the zeolite of example 1 with a 0.58 wt % platinum content. The product at 250° C. contained: 54% n-hexane, 20% 2-methylpentane and 6% 3-methylpentane. The n-hexane yield was 15% at 200° C., and 1% at 150° C. EXAMPLE 15 The experiment of example 6 was operated, but using the zeolite of example 1 with 0.58 wt % platinum content. The product at 250° C. contained 50% n-hexane, 26% 2-methylpentane, 8% 3-methylpentane and 6% dimethylbutanes. The n-hexane yield was 19% at 200° C. and 1% at 150° C. EXAMPLE 16 The experiment of example 14 was repeated with catalyst having 0.18 wt % platinum. The product from 2-methylpentene-1 at 250° C. contained 12% n-hexane. EXAMPLE 17 The experiment of example 15 was repeated with catalyst having 0.18 wt % platinum. The product from 3,3-dimethylbutene-1 at 250° C. contained 1% n-hexane. EXAMPLE 18 The ZSM-5 zeolite of example 1 (2 g) was treated with tetrammineplatinum dichloride (0.04 g) according to the method of example 2 and subsequently treated according to the method of example 3. The sample was at 200° C. product containing 90% 2-methylpentane and 9% 3-methylpentane, and at 300° C. product containing 37% 2-methylpentane, 24% 3-methylpentane and 26% n-hexane. EXAMPLE 23 3,3-dimethylbutene was hydroisomerised according to the method of example 6 over the catalyst of example 22 to give at 200° C. product containing 44% 2,2-dimethylbutane and 51% 2,3-dimethylbutene, and at 300° C. product containing 33% 2-methylpentane, 23% 3-methylpentane, 7% 2,2-dimethylbutane, 10% 2,3-dimethylbutane and 22% n-hexane. EXAMPLE 24 ZSM-:11 zeolite (1 g) was treated with tetrammineplatinum dichloride (0.04 g) according to the method of example 2 and subsequently treated according to the method of example 3 to give catalyst containing 0.91 wt % platinum and 0.68 wt % aluminium. 2-Methylpentene-1 was hydroisomerised according to the method of example 4 over the catalyst so prepared. At 150° C., 99% of the product comprised 2-methylpentane. At 250° C. the product contained 40% n-hexane, 40% 2-methylpentane and 18% 3-methylpentane. EXAMPLE 25 The catalyst of example 24 was used to hydroisomerised 3,3-dimethylbutene-1 according to the method of example 6. The product obtained at 150° C. contained 86% 2,2-dimethylbutane with 13% 2,3-dimethylpentane. The product obtained at 300° C. contained 16% n-hexane, 27% 2-methylpentane, 19% 3-methylpentane, 26% 2,2-dimethylbutane and 7% 2,3-dimethylbutane. at 200° C. product containing 90% 2-methylpentane and 9% 3-methylpentane, and at 300° C. product containing 37% 2-methylpentane, 24% 3-methylpentane and 26% n-hexane. EXAMPLE 23 3,3-dimethylbutene was hydroisomerised according to the method of example 6 over the catalyst of example 22 to give at 200° C. product containing 44% 2,2-dimethylbutane and 51% 2,3-dimethylbutene, and at 300° C. product containing 33% 2-methylpentane, 23% 3-methylpentane, 7% 2,2-dimethylbutane, 10% 2,3-dimethylbutane and 22% n-hexane. EXAMPLE 24 ZSM-11 zeolite (1 g) was treated with tetrammineplatinum dichloride (0.04 g) according to the method of example 2 and subsequently treated according to the method of example 3 to give catalyst containing 0.91 wt % platinum and 0.68 wt % aluminium. 2-Methylpentene-1 was hydroisomerised according to the method of example 4 over the catalyst so prepared. At 150° C., 99% of the product comprised 2-methylpentane. At 250° C. the product contained 40% n-hexane, 40% 2-methylpentane and 18% 3-methylpentane. EXAMPLE 25 The catalyst of example 24 was used to hydroisomerised 3,3-dimethylbutene-1 according to the method of example 6. The product obtained at 150° C. contained 86% 2,2-dimethylbutane with 13% 2,3-dimethylpentane. The product obtained at 300° C. contained 16% n-hexane, 27% 2-methylpentane, 19% 3-methylpentane, 26% 2,2-dimethylbutane and 7% 2,3-dimethylbutane. EXAMPLES 26-27 Examples 26-27 teach the use of non-aluminosilicate zeolites. EXAMPLE 26 The experiment of example 4 was repeated using a ferrasilicate zeolite of ZSM-5 structure, activated according to the procedure of examples 2 and 3. The catalyst contained 1.23 wt % iron and 0.18 wt % platinum. 2-methylpentene-1 at 250° C. gave a product containing 26% n-hexane. EXAMPLE 27 The experiment of example 26 was repeated using a gallosilicate of ZSM-5 structure containing 2.98 wt % gallium and 0.90 wt % platinum. 2-methylpentene-1 at 250° C. gave a product containing 42% n-hexane. EXAMPLES 28-32 These examples teach the advantage of using "high-area" zeolite such as that in example 1 for hydroisomerisation of highly branched olefins such as dimethyl-butene-1. EXAMPLE 28 The experiment of example 14 was repeated but utilizing a catalyst prepared from ZSM-5 zeolite of spheral aggregate morphology which differs from that of example 14 in not being a "high-area" zeolite. The catalyst contained 0.96 wt % aluminium and 0.86 wt % platinum. The product at 250° C., from 2-methylpentene-1 feed, contained 56% n-hexane, 31% 2-methylpentane and 10% 3-methylpentane, with only 3C % of the product being hydrocarbons of 6 carbon atoms. EXAMPLE 29 The experiment of example 15 was repeated with the catalyst of experiment 28. The product at 250° C. contained 25% n-hexane, 45% 2-methylpentane, 13% 3-methylpentane, 1% 2,2-dimethylbutane and 5% 3-methylbutane. EXAMPLE 30 The catalyst of experiment 28 was used to repeat the experiment of Example 8. The propylene polymer gasoline gave at 200° C. a product of which 58% was C 9 hydrocarbons. The product contained in particular 1% n-nonane and 2% methyloctanes. EXAMPLE 31 The catalyst of example 14 was used to repeat the experiment of example 8. Then propylene polymer gasoline gave at 200° C. a presence of which 54% was C 9 hydrocarbons. The product contained 3% n-nonane and 15% methyloctanes. EXAMPLE 32 Two samples of ZSM-5 zeolite were prepared the one of conventional (spheral aggregate) morphology and the other being a "high-area" zeolite, as in example 1, each having a 0.44 wt % aluminium content. Each was treated according to the method of examples 2 and 3 so as to have a 0.80 wt % platinum content. Each of the catalysts was used to hydroisomerise propylene polymer gasoline according to the method of example 8. At 150° each of the catalysts gave product containing 56-62% C 9 hydrocarbons, including 51-58% C 9 hydrocarbons having two or more chain branches. At 200° the "high-area" zeolite catalyst gave product containing 5% n-nonane, 15% methyloctanes and 36% more highly branched nonanes, whereas the other catalyst gave 2% nonane, 11% methyloctanes and 42% more highly branched nonanes. At 230° C. the "high-area" zeolite catalyst gave 10% n-nonanes 14% methyloctanes and 6% more highly branched nonanes, whereas the other catalyst gave 6% n-nonanes, 8% methyloctanes and 13% more highly branched nonanes. EXAMPLE 33 A sample of "high-area" ZSM-5 zeolite prepared according to the general procedure of example 1, but with less sodium aluminate so as to give zeolite of 0.44 wt % aluminium content, was loaded with 0.34 wt % platinum according to the procedure of example 2. 1.0 g of the catalyst was then packed into a stainless steel tubular reactor (of 10.5 mm internal diameter) and activated by treatment first in flowing oxygen (200 cc/min) then flowing hydrogen (200 cc/min) at 1 bar pressure following the procedure of example 3. The reactor was then fed from the top with hydrogen (100 cc/min) and propylene polymer gasoline (6 cc/hr) and maintained at a pressure of 10 bar by a pressure control valve at its lower exit end. At a reactor temperature of 200° C., the product contained 10% n-nonanes, 8% methyloctanes and 44% more highly branched nonanes. At 250°, the corresponding yields were 3%, 16% and 33% respectively. It will be clearly understood that the invention in its general aspects is not limited to the specific details referred to hereinabove.
Branched olefins of at least 4 carbon atoms are hydroisomerized to a less branched alkane by contact with a hydrogen containing gas and a shape selective zeolite which has at least 1 metal of the Pt group supported primarily within the channels of said zeolite.
2
BACKGROUND OF THE INVENTION The present invention relates to a foamable antifungal composition for the treatment of various skin conditions. Antifungal agents are well known, and include macrolide antibiotics such as griseofulvin, and imidazoles such as clotrimazole and ketoconazole. Ketoconazole was originally described by Heeres et al in U.S. Pat. No. 4,335,125, in which its principal utility was an antifungal compound useful in the treatment of a variety of conditions including sebborheic dermatitis, dandruff, “jock itch” and tinea. Antifungal compositions are traditionally applied as lotions or creams. There are however disadvantages to these forms. In particular, the formulations are frequently very viscous requiring substantial rubbing to achieve penetration into the effected area, an act in itself which causes discomfort and sometimes irritation. If the viscous formulations are not vigorously applied, the active antifungal agent does not necessarily reach the site requiring treatment being the epidermis of the skin. Non-viscous creams and lotions are wont to flow off the effected site before penetration is achieved. One final disadvantage is that cream and lotion bases in themselves can add to site irritation depending on their content. Ketoconazole was disclosed in U.S. Pat. No. 4,569,935 to be useful in the topical treatment of psoriasis and seborrheic dermatitis. Pursuant to this utility, ketoconazole has been marketed in a 2% shampoo formulation for the treatment of scaling due to dandruff, sold under the brand name “Nizoral®”. This shampoo is applied by the user and then removed shortly, for example 3-5 minutes, after its application by rinsing with water. The active agent is thus only in contact with the area to be treated for a very limited time. Another patent describing ketoconazole based shampoos is U.S. Pat. No. 5,456,851 in the name of JOHNSON & JOHNSON CONSUMER PRODUCTS, INC which aims to provide good cosmetic properties to the shampoo including lather, and to retard degradation of the ketoconazole. This composition is a foaming formulation. The disadvantage of such shampoo formulations is that during normal usage, the formulation does not remain on the scalp for a period of time sufficient to allow the antifungal agent to achieve its maximal therapeutic effect since they are designed to be applied, for example in the shower or bath, and shortly after rinsed off with water. Typically, the application instructions for such shampoos suggest that the formulation be removed after 3-5 minutes. In order to achieve maximal therapeutic effect, one alternative such as is described in AU 80257/87, is to provide a high quantity of residual solids which remain after application to treat the offending skin condition. There is disclosed in AU 80257/87 a foam composition for the delivery of minoxidil. The formulations disclosed in this document all contain a high percentage of non-volatile residues, including propylene glycol. While it is not disclosed why these formulations contain such a large amount of propylene glycol, it is postulated that the propylene glycol is probably required either to enhance the penetration and/or to improve the solubility of the minoxidil. The disadvantage of a composition with a high residual content is that the non-volatile residues are retained at the site of application and therefore feel unpleasant and unattractive to the user. Alternatives to ketoconazole and minoxidil are described in AU-A-35717/93 in the name of SMITH KLINE BEECHAM PLC which discloses compositions including a novel androstene steroid for use in the treatment of acne and sebborrhea, and AU-A-48851/96 in the name of MEDEVA PLC which describes the use of betamethasone in a quick breaking foam including a buffering agent for use in the treatment of skin diseases and particularly scalp psoriasis. It is an aim of this invention to provide an antifungal composition which is effective in its treatment of fungal skin conditions but which is also pleasant to use. SUMMARY OF THE INVENTION To this end, in a first aspect of the invention, there is provided a topical, foamable composition including at least one antifungal agent, said composition characterised in that said at least one antifungal agent is able to penetrate the upper layers of the skin and is retained in or on an area to be treated for a prolonged period of time, and in that it has a residual non-volatile component content of less that 25%. It has been surprisingly found that the antifungal composition of the present invention has a commercially acceptable cosmetic appeal and during normal usage allows greater penetration and retention of the antifungal agent in the upper layers of the skin, particularly in the epidermis, thus providing a reservoir of active agent available to achieve a sustained antifungal effect when compared against known formulations. This latter feature leads to enhanced pharmaceutical appeal as well as cosmetic appeal. Moreover, the residual solids content of the formulation is so low as to not provide discomfort and irritation to the user The term “prolonged period of time” is meant to encompass periods of time sufficiently long so as to enable the active agent present to be substantially fully absorbed by the organism being treated, or substantially fully metabolised by the patient being treated. In a preferred embodiment, the one or more antifungal agents is selected from the group consisting of diols, allylamines (including naftifine and terbinafine), polyene macrolide antibiotics (including amphotericin and nystatin), triazole derivatives (such as fluconazole), fatty acids (such as caprylic and propionic acid), amorolfine, ciclopirox, olamine, benzoic acid, flucytosine, haloprogin, tolnaftate, undecenoic acid and its salts, griseofulvin and imidazole compounds. More preferably, the antifungal is an imidazole compound. Most preferably, the antifungal agent is ketoconazole or chlorphenesin (3-(4-Chlorphenoxy)propane-1,2-diol). Preferably the compositions according to the invention have a residual non-volatile component content of less that 10%, and more preferably of less than 6%. In a preferred embodiment the topical, foamable composition is provided as a mousse. In a further preferred embodiment the mousse is a temperature sensitive mousse, which breaks down rapidly when exposed to the skin temperature. In a still further embodiment, the composition is an ethanolic mousse including a lower alcohol content of greater than 10%, more preferably greater than 50% and a hydrocarbon gas content propellent of less than 60%, more preferably less than 10%. In an alternative embodiment the composition is an aqueous mousse including no lower alcohol content and a hydrocarbon gas content propellent of less than 60%, more preferably less than 10%. (Unless specified otherwise in the specification, all % are based on the total weight of the composition.) In the temperature sensitive mousse, the long chain alcohol may be chosen from, for example, cetyl, stearyl, lauryl, myristyl and palmityl alcohols and mixtures of two or more thereof. The lower alcohol may preferably be chosen from methyl, ethyl, isopropyl and butyl alcohols, and mixtures of two or more thereof. Ethanol has been found to be particularly preferred. Surfactants utilised in the temperature sensitive mousse may preferably be chosen from ethoxylated sorbitan stearate, palmitate, oleate, nonyl phenol ethoxylates and fatty alcohol ethoxylates, and mixtures of two or more thereof. Thus, for example, Polysorbate 60 (a mixture of partial stearic esters of sorbitol and its anhydrides copolymerised with approximately 20 moles of ethylene oxide for each mole of sorbitol and its anhydrides) has been found to be particularly preferred. The surfactant enhances the long chain alcohol solubility in the system and enhances mousse formation. In a further aspect of the invention, there is provided a foamable composition including up to 5% of long chain alcohols up to 5% of quaternary compound up to 10% of propylene glycol up to 5% of antifungal agent up to 90% of lower alcohol solvent up to 5% of surfactant 5-95% of water, and up to 20% of a hydrocarbon gas propellant Preferably, the long chain alcohol is cetyl or stearyl alcohol or mixtures thereof. Preferably, the quaternary compound is quaternium oxy ethyl alkyl ammonium phosphate commercially available under the trade name, Dehyquart SP. Preferably, the lower alcohol solvent is ethanol or propanol or mixtures thereof. Suitable gas propellants include non-toxic gas propellants suited to foamable cosmetic and pharmaceutical compositions and known to those skilled in the art. Thus, one may select the propellant from propane, butane, dichloro difluoro methane, dichloro tetrafluoro ethane, octafluoro cyclobutane, and mixtures of two or more thereof. It is necessary to select a propellant most compatible with the entire system. The maximum level of propellant will be determined as the amount miscible with the utilized water/lower alcohol ratio. In addition to acting as a propellant, the propellant will also act as a solvent for the long chain alcohol and active substances in the aqueous/alcoholic system. In a second aspect of the invention there is provided a composition for the treatment of fungal skin conditions including dandruff, seborrheic dermatitis, tinea, jock itch and the like, said composition characterised in that it is a foamable mousse applicable to the skin of the user in the substantial absence of water and without substantially immediate removal by washing. In a preferred embodiment of this aspect of the invention, said composition has a non-volatile component content of less than 25%, preferably less than 10% and more preferably less than 6%. In a more preferred embodiment of this aspect of the invention, the mousse is a temperature sensitive mousse, which breaks down rapidly when exposed to the skin temperature. In a still further preferred embodiment, the composition is a mousse including a lower alcohol content of greater than 10%, more preferably greater than 50% and a hydrocarbon gas content propellent of less than 60%, more preferably less than 10%. In a further aspect of the invention there is provided a topical, foamable composition including an antifungal agent characterised in that upon application to the skin of a user a penetration of at least 10 μg/cm 2 is achieved in the epidermis within one hour of application and sustained over a period of at least 23 hours. When the preferred active agent is ketoconazole, the invention provides a topical, foamable composition characterised in that upon application to the skin of a user a penetration of at least 30 μg/cm 2 is achieved in the epidermis within one hour of application and sustained over a period of at least 23 hours. When the preferred active agent is chlorphenesin, the invention provides a topical, foamable composition characterised in that upon application to the skin of a user a penetration of at least 10 μg/cm 2 is achieved in the epidermis within one hour of application and sustained over a period of at least 23 hours. In a still further aspect of the invention, there is provided a method of treating fungal infections, particularly tinea, jock itch, dandruff and sebborheic dermatitis by applying to the affected area of a patient requiring such treatment the antifungal composition of the present invention. In a preferred embodiment of this aspect of the invention, the composition is allowed to remain on the affected area for an extended period of time. In this context “extended period of time” means a length of time greater than the length of time that prior art topical compositions such as shampoos are prescribed to remain in contact with the affected area. Usually, shampoos are designed to be washed off within 5 minutes. More preferably, when the composition is used to treat dandruff or sebborheic dermatitis, it is applied at one wash or between washes and is allowed to remain on the site of application such as the scalp or hair until the site of application is subsequently washed again. The invention also encompasses the use of an antifungal agent in the preparation of a topical foamable composition for the treatment of fungal diseases including dandruff, tinea, jock itch and sebborheic dermatitis, the topical foamable composition being characterised in that it is able to penetrate the epidermis of the skin and is retained in or on an area to be treated for a prolonged period of time, and in that it has a non-volatile component content of less that 25%. BRIEF DESCRIPTION OF THE DRAWINGS The present subject matter can be understood with reference to the following drawings. FIG. 1 is a graphical representation of the time course of the ketoconazole penetrating across human epidermis to receptor fluid. FIG. 2 is a graphical representation of the time course of ketoconazole retained in the epidermis. FIG. 3 is a graphical representation of the levels of retention of ketoconazole on the skin, the levels of retention of the ketoconazole in the skin and the amount of ketoconazole passed through the skin in the tests using a mousse according to one embodiment of the present subject matter with the same measures using Nizoral®. FIG. 4 is a graphical representation of the HPLC standard curve for ketoconazole. FIG. 5 is a graphical representation of the amount of ketoconazole retained in the skin versus the time after application of the formulation according to one embodiment of the present subject matter. FIG. 6 is a graphical representation of the HPLC standard curve for chlorphenesin. FIG. 7 is a graphical representation of the amount of chlorphenesin retained in the skin versus the time after application of the formulation according to one embodiment of the present subject matter. DETAILED DESCRIPTION OF THE INVENTION Two formulations of the present invention were prepared. 1) 0.5% ketoconazole mousse composition Cetyl alcohol 1.10 Stearyl alcohol 0.50 Quaternium 52 (50%) 1.00 Propylene Glycol 2.00 Ketoconazole USP 0.50 Ethanol 95PGF3 60.55 Deionised Water 30.05 P75 Hydrocarbon Propellant 4.30 2) 1% ketoconazole mousse composition Cetyl alcohol 1.10 Stearyl alcohol 0.50 Quaternium 52 (50%) 1.00 Propylene Glycol 2.00 Ketoconazole USP 1.00 Ethanol 95PGF3 60.20 Deionised Water 29.90 P75 Hydrocarbon Propellant 4.30 The compositions were prepared by dissolving the active in the ethanol. the cetyl and stearyl alcohol are then added to the heated solution and mixed until dissolved. The quaternium 52, propylene glycol and water are then added and stirred until homogenous, while maintaining the elevated temperature. The solution is then dispensed into aerosol cans where the aerosol valve is then fitted and the can charged with propellant. EXAMPLE 1 A study was undertaken to compare the epidermal penetration of the two mousse compositions above, against the commercially available Nizoral® shampoo containing 2% ketoconazole. In particular the respective formulations were applied and removed as for a conventional shampoo so as to compare the penetration of the respective formulations into the epidermis. Equipment and Materials in vitro Franz diffusion cells (surface area 1.33 cm 2 , receptor volume 3.5 ml) incorporating human epidermis HPLC equipment: Shimadzu automated HPLC system with uv detector, bovine serum albumin dissolved in phosphate buffered saline (pH 7.4) as receptor phase to mimic physiological conditions. Experimental Protocol finite dosing (50 mg for shampoo and 100 mg for mousses) receptor phase: 4% BSA in phosphate buffered saline at pH 7.4 sampling time: 6, 10, 24 hours (amount in receptor phase (μg/cell) and epidermis (μg/cell)) non-occlusion study each time period and formulation conducted in triplicate. Application Procedure Shampoo: 50 mg shampoo (equivalent to 1 mg ketoconazole) dose applied to pre-wetted skin with stirring and rinsed off with deionised water after 4 minutes. Mousse: 100 mg mousse (equivalent to 1 mg ketoconazole for 1% mousse and 500 μg ketoconazole for 0.5% mousse dose applied (not rinsed off). Epidermal Retention Protocol Epidermis removed from cell following time interval, rinsed with distilled water and dried to remove ketoconazole remaining on surface. Ketoconazole extracted from epidermal sample by soaking in methanol for 1 hour. This procedure is repeated with a second volume of methanol for 30 mins. The methanol samples are combined for HPLC analysis (this procedure has been validated with a 99% recovery rate). HPLC Assay Column: Nova Pak C 18 steel column, 3.9 × 150 mm Mobile phase: 70% MeOH in 0.02 M phosphate buffer, pH 6.8 Wavelength: 254 nm Flow rate: 1.3 ml/min Injection volume: 10 μl Retention time: about 7 min Results Table 1 shows the cumulated ketoconazole in both the receptor phase and the epidermis at defined time points following application of the mousse according to the invention and the shampoo of the prior art. TABLE 1 Ketoconazole μg/cell 6 hours 10 hours 24 hours Sample receptor epidermis receptor epidermis receptor epidermis 0.5%  4.96  33.15  9.04 69.46 14.69 42.10 mousse 0.5%  2.83  35.71 18.06 48.04 24.77 39.19 mousse 0.5% 14.37 34.3 21.3  55.29  9.82 48.27 mousse Mean ± SD  7.4 ± 6.1 34.4 ± 1.3  16.1 ± 6.4  57.6 ± 10.9 16.4 ± 7.6  43.2 ± 4.6 1% mousse 12.86 46.4 31.50 67.51 21.90 51.43 1% mousse 10.03 61.8 11.05 55.65 35.85 46.64 1% mousse 18.61 38.6 19.38 56.83 10.72 43.28 Mean ± SD 13.8 ± 4.4 48.9 ± 11.8 20.6 ± 10.3  60 ± 6.5 22.8 ± 12.6 47.1 ± 4.1 2% shampoo N N N  0.89 N N 2% shampoo N N N  0.28 N  0.38 2% shampoo N N N N N  0.34 Mean ± SD — — — 0.39 ± 0.46 —  0.24 ± 0.21 N: not detectable (assuming to be zero for calculating mean and SD) —: not available Table 2 shows the cumulated ketoconazole in both receptor (expressed as μg/ml receptor fluid) and epidermis (expressed as μg/cm 2 surface area) at defined time points following application of the mousse according to the present invention and the shampoo of the prior art. TABLE 2 Ketoconazole μg 6 hours 10 hours 24 hours Sample receptor epidermis receptor epidermis receptor epidermis 0.5% 1.42 26.95 2.58 56.47 4.20 34.23 mousse 0.5% 0.81 29.03 5.46 39.06 7.08 31.86 mousse 0.5% 4.11 27.89 6.09 44.95 2.81 39.24 mousse Mean ± SD 2.11 ± 1.76 27.96 ± 1.04 4.61 ± 1.82 46.83 ± 8.86 4.70 ± 2.18 35.11 ± 3.77 1% mousse 3.67 37.72 9.00 54.89 6.26 41.81 1% mousse 2.87 50.24 3.16 45.24 10.24  37.92 1% mousse 5.32 31.38 5.54 46.20 3.06 35.19 Mean ± SD 3.95 ± 1.25 39.78 ± 9.60 5.90 ± 2.94 48.78 ± 5.31 8.52 ± 3.80 38.31 ± 3.33 2% shampoo N N N  0.72 N N 2% shampoo N N N  0.23 N  0.31 2% shampoo N N N N N  0.28 Mean ± SD — — —  0.32 ± 0.37 —  0.20 ± 0.17 N: not detectable (assuming to be zero for calculating mean and SD) —: not available FIG. 1 shows the time course of the ketoconazole penetrating across human epidermis to receptor fluid. The closed points of the graph represent 0.5% mousse, the open points represent 1.0% mousse. Data are the mean±SD of triplicate (from Table 2). FIG. 2 represents the time course of ketoconazole retained in the epidermis. The closed points of the graph represent 0.5% mousse, the open points represent 1.0% mousse. Data are the mean±SD of triplicate (from Table 2). FIG. 3 compares the levels of retention of ketoconazole on the skin, the levels of retention of the ketoconazole in the skin and the amount of ketoconazole passed through the skin in the tests using a mousse according to the invention with the same measures using Nizoral®. Note that ketoconazole levels found after application of the Nizoral® shampoo were low and thus are not visible in this figure It can readily be observed from the results of example 1 that: 1. the ketoconazole in the mousse compositions of the present invention penetrated the skin in appreciable quantity; 2. the ketoconazole in the mousse composition of the present invention was preferentially retained in the epidermis compared to penetration into the receptor solution; 3. application of the prior art shampoo, Nizoral®, resulted in insignificant amounts of ketoconazole in the epidermis and penetrating to the receptor phase at any of the time points following application using a standardised shampooing procedure; 4. comparison of the 1% and 0.5% mousse formulations of the present invention shows that there is little difference in epidermal and receptor phase concentrations. EXAMPLE 2 A second study was undertaken to compare the skin penetration and retention of ketoconazole from the 1% ketoconazole mousse composition of the current invention with Nizoral® Shampoo (1% w/w). The 1% mousse composition had a total residue content of 5.1% solids including active. Equipment and Materials In vitro Franz diffusion cells (surface area 1.33 cm 2 , receptor volume 3.5 mL) incorporating full thickness human skin, HPLC equipment: Shimadzu automated HPLC system with uv detector. Experimental Protocol Finite dosing (50 mg of each formulation placed onto skin surface), Receptor phase: 4% bovine serum albumin (BSA) in phosphate buffered saline (PBS) pH 7.4, Sampling times for skin retention: 15 minutes, 1, 12, 24 hours, Sampling times for skin penetration to receptor phase: 12, 24 hours, Amount of ketoconazole in full thickness skin and receptor phase measured by HPLC assay following suitable extraction procedure, Non-occlusion study, Triplicate measurements. Application Procedure Both mousse and shampoo were applied and left in contact with the skin for the duration of the penetration study. Following this the formulation was washed off the skin with distilled water prior to sample extraction procedure and HPLC assay for ketoconazole content. HPLC Assay Column: Nova Pac C 18 steel column, 3.9 × 150 mm (Waters) Mobile phase: 70% MeOH in 0.02M PBS, pH 6.8 Wavelength: 254 nm Flow rate: 1.0 mL/min Injection volume: 10 μL Retention time: approximately 8 mins Full Thickness Skin Retention Protocol Full thickness skin was removed from cell following time interval, rinsed with distilled water and dried to remove ketoconazole remaining on surface. Ketoconazole was extracted from full thickness skin sample by soaking in methanol for 1 hour. This procedure was repeated with a second volume of methanol for 30 mins. The methanol samples were combined from HPLC analysis. [This procedure has been validated with a 99% recovery rate]. Results FIG. 4 shows the HPLC standard curve for ketoconazole. Table 3 shows the amount of ketoconazole retained in the skin (μg/cm 2 ) at 15, 60 minutes, 12 and 24 hours following application of the mousse according to the invention, or the shampoo of the prior art. TABLE 3 Ketoconazole retained in skin (μg/cm 2 ) at 15, 60 mins, 12, 24 hours following application of mousse or shampoo. Ketoconazole in skin (μg/cm 2 ) mean ± SEM Sample 15 mins 60 mins 12 hrs 24 hrs Shampoo 11.2 ± 0.91 24.2 ± 1.58 39.7 ± 12.3 70.1 ± 18.8 Mousse 19.6 ± 2.5  44.1 ± 8.27 128.37 ± 19.1  228.57 ± 14.8  Table 4 shows the amount of ketoconazole penetrated to the receptor phase (μg/mL) at 12, 24 hours following application of the mousse according to the invention, or the shampoo of the prior art. TABLE 4 Ketoconazole penetrated to receptor phase (μg/mL) at 12, 24 hours following application of mousse or shampoo. Ketoconazole in receptor (μg/mL) mean ± SEM Sample 15 mins 60 mins 12 hrs 24 hrs Shampoo — — n 0.04 ± 0.04 Mousse — — 0.07 ± 0.05 0.30 ± 0.04 n: not detectable —: not assayed FIG. 5 shows the amount of ketoconazole retained in the skin versus the time after application of the formulation according to the invention. Data are the mean±SEM (n=3) from Table 4. The mousse formulation according to the invention demonstrated significantly greater skin retention of ketoconazole than the shampoo formulation of the prior art over the 24 hour period. It can readily be observed from the results of example 2 that: 1. penetration of ketoconazole to the receptor phase over the 24 hours following application was minimal for both shampoo and mousse. 2. skin retention of ketoconazole was significantly greater following application of the mousse formulation compared to the shampoo (p<0.05). EXAMPLE 3 A third study was undertaken to compare the skin penetration and retention of two formulations according to the invention in which the active anti fungal agent was chlorphenesin (0.5% w/w). One formulation was ethanolic and had a total residue content of 2.5% solids including active, the other formulation was aqueous and had a total residue content of 4.6% solids including active. Aqueous Formulation % w/w Chlorphenesin 0.50 Cetyl alcohol 0.70 Stearyl alcohol 0.30 Icocetyl alcohol 2.50 Ceteth 20 0.50 Preservative 0.10 Purified Water 90.40 P75 Hydrocarbon Propellant 5.00 Ethanolic Formulation Chlorphenesin 0.50 Cetyl alcohol 1.10 Stearyl alcohol 0.50 Polysorbate 0.40 Ethanol 95% 60.79 Purified Water 32.41 P75 Hydrocarbon Propellant 4.30 Equipment and Materials In vitro Franz diffusion cells (surface area 1.33 cm 2 , receptor volume 3.5 mL) incorporating full thickness human skin, HPLC equipment: Shimadzu automated HPLC system with uv detector. Experimental Protocol Finite dosing (50 mg of each formulation placed onto skin surface), Receptor phase: 4% bovine serum albumin (BSA) in phosphate buffered saline (PBS) pH 7.4, Sampling times for skin retention: 15 minutes, 1, 12, 24 hours, Sampling times for skin penetration to receptor phase: 12, 24 hours, Amount of chlorphenesin in full thickness skin and receptor phase measured by HPLC assay following extraction into acetonitrile (ACN) and methanol (MeOH) (9:1), Non-occlusion study, Triplicate measurements. Application Mousses according to the invention were applied and left in contact with the skin for the duration of the penetration study. Following this the formulation was washed off with distilled water prior to the extraction and HPLC for chlorphenesin content. HPLC Assay Column: Nova Pac C 18 steel column, 3.9 × 150 mm (Waters) Mobile phase: 30% ACN Wavelength: 280 nm Flow rate: 1.0 mL/min Injection volume: 20 μL Retention time: approximately 3.6 mins Skin Retention Protocol Skin was removed form the cell following time interval and rinsed with distilled water to remove chlorphenesin on the surface. Chlorphenesin was extracted from homogenised skin by soaking in 1 mL ACN-MeOH mix for 1 hour. This procedure was repeated for a further four 30 minute periods. The five samples were combined for HPLC analysis. [The procedure was validated with a 99% recovery rate]. Results FIG. 6 shows the HPLC standard curve for chlorphenesin. Data are the mean±standard deviation (n=3). Table 5 shows the amount of chlorphenesin retained in the skin (μg/cm 2 ) at 15, 60 minutes, 12 and 24 hours following application of the mousse according to the invention. TABLE 5 Chlorphenesin in skin (μg/cm 2 ) mean ± SD Sample 15 mins 60 mins 12 hrs 24 hrs aqueous 12.8 ± 4.8 13.2 ± 1.1 47.6 ± 13.2 35.8 ± 2.2 non-aqueous 16.7 ± 5.5   22 ± 9.7 93.8 ± 17.3 57.4 ± 20.4 Table 6 shows the amount of chlorphenesin penetrated to the receptor phase (μg/mL) at 12, 24 hours following application of the mousse according to the invention. TABLE 6 Chlorphenesin in receptor (μg/mL) mean ± SD Sample 15 mins 60 mins 12 hrs 24 hrs aqueous — — 2.9 ± 0.4 5.6 ± 1.1 non-aqueous — —   5 ± 0.7 5.1 ± 1.5 :— not assayed FIG. 7 shows the amount of chlorphenesin retained in the skin versus the time after application of the formulation according to the invention. Data are the mean±standard deviation (n=3) from Table 5. The open points are the aqueous formulation. The closed points represent the ethanolic formulation. It is readily observed from the results of example 3 that active agents other than ketoconazole formulated as both ethanolic and aqueous compositions achieve the desired penetration and retention levels for effective treatment of fungal skin conditions. It will be appreciated that the scope of this invention goes beyond the specific formulations exemplified to encompass topical foamable antifungal compositions having like components to those specifically mentioned but having characteristic penetration and retention levels in the skin of the user, and low levels of residual solid content as defined.
A topical, foamable composition is provided that includes at least one antifungal agent that is able to penetrate the upper layers of skin and is retained in or on an area to be treated for a prolonged period of time, and that has a residual non-volatile component content of less than 25%. In addition, a method of treating fungal diseases including jock itch, tinea, dandruff and sebborheic dermatitis is provided, and includes applying to the affected area of a patient requiring such treatment an antifungal composition.
8
BACKGROUND This invention relates generally to environmental control systems for an aircraft, and specifically to air conditioner systems. A typical environmental control system for an aircraft includes an air conditioning pack mounted to the outside of the pressure vessel of the aircraft. Pressurized air, such as bleed air from the engine, is provided and processed by going through primary and secondary heat exchangers. The output air from the air cycle machine is typically subfreezing air with moisture, ice or snow mixed in it. The output then goes through a duct to a condenser to flow through the condenser before it flows to the aircraft cabin. Sometimes heat is added to the system to prevent freezing and blockage within the system. SUMMARY An apparatus for use with an aircraft air conditioning machine to provide conditioned air to an aircraft cabin includes a recirculation air mixer to mix recirculation air and cold air from a turbine in the air conditioning machine as mixed air, the recirculation air mixer including a cold inlet, a plenum, a recirculation air inlet connected to an annulus and a plurality of injectors for injecting the recirculation air from the annulus into the plenum; and a condenser connected to the recirculation air mixer, the condenser including an inlet to receive air from a heat exchanger, a chamber where air from the recirculation air mixer enters to condense the air received through the inlet from the heat exchanger, an outlet for transferring the condensed air to the turbine, and an outlet for transferring conditioned air to the aircraft cabin. A method of mixing air for use in an aircraft cabin includes condensing air through a condenser to remove moisture from the air; expanding the condensed air through a turbine to cool the air; mixing the expanded air flowing axially into a recirculation air mixer with recirculation air from the cabin flowing radially into the recirculation air mixer. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A shows a perspective view of an air conditioning machine. FIG. 1B shows a plan view of the air conditioning machine of FIG. 1A . FIG. 2A shows a perspective view of a condenser with hybrid recirculation air mixer. FIG. 2B shows a perspective view of the hybrid recirculation air mixer of FIG. 2A . DETAILED DESCRIPTION FIG. 1A shows a perspective view of air conditioning machine 10 , and FIG. 1B shows a plan view of air conditioning machine 10 . Air conditioning machine 10 includes hot air inlet 11 , ram air inlet 12 , dual heat exchanger 14 , ram air fan 16 with ram air outlet 17 , compressor 18 , turbine 20 , turbine bypass valve 21 , turbine diffuser cone 22 , recirculation air mixer 24 , condenser 26 , water collector 28 and outlet 30 . Dual heat exchanger 14 includes a primary heat exchanger and a secondary heat exchanger in series. Condenser 26 includes inlet 36 and outlet 38 . Recirculation air mixer 24 includes recirculation air inlet 40 and cold air inlet 42 . Dimension L is shown as the length of air conditioning machine, and can be about 42 inches (about 1067 mm). Arrows show flow direction through ducts in machine 10 . Ram air fan 16 connects to dual heat exchanger 14 . Dual heat exchanger 14 connects to compressor 18 through duct 45 connecting to primary heat exchanger, and connects to condenser 26 through duct 47 connecting to secondary heat exchanger. Condenser connects to turbine 20 through duct 49 , which includes water collector 28 . Turbine 20 connects to turbine diffuser cone 22 , which then connects to recirculation air mixer 24 , and through condenser 26 to outlet 30 . Air conditioning machine 10 can be mounted to the pressure vessel of an aircraft and works to supply conditioned air to the aircraft cabin at the proper pressure and temperature. Dual heat exchanger 14 receives compressed air from an engine at inlet 11 . Typically this air is bled off the engine and compressed, having gone through regulating valves to set the pressure. The bleed air goes into primary heat exchanger, where it is cooled using ram air fan 16 . Ram air fan 16 typically draws ambient air from outside the aircraft into heat exchanger 14 to cool process flow air and then exhausts the cooling ram air through outlet 17 . This ambient air acts to cool air entering primary heat exchanger. Primary heat exchanger can, in one example, cool air from about 400 degrees F. (204 degrees C. or 477 Kelvin (“K”)) to about 200 degrees F. (93 degrees C. or 366 K). This cooled air is then sent to compressor 18 through duct 45 , where it is compressed. A typical compression can be from about 45 psi (310 kPa) to about 80 psi (552 kPa) at 350 degrees F. (177 degrees C. or 450 K). Next air is transferred to secondary heat exchanger, which also uses ram air to cool the primary airflow further, for example, from about 350 degrees F. (177 degrees C. or 450 K) to about 150 degrees F. (66 degrees C. or 339 K). The process flow air then flows to condenser 26 through duct 47 . Condenser 26 condenses air by lowering the air temperature to a point where water condenses out of the airflow and into water collector 28 . This cooling is done by subjecting the flow to subfreezing air from turbine 20 . Process air flows through condenser 26 outlet 38 to turbine 20 . Turbine 20 expands the air to bring it to a subfreezing temperature. Turbine bypass valve 21 can be used to add heat to turbine 20 in some operating modes. Typically, valve 21 would be closed on warm days, when there is high humidity and large amounts of cooling from machine 10 are required. The cold air from turbine 20 is directed through turbine diffuser cone 22 to recirculation air mixer 24 inlet 42 axially. Recirculation air mixer 24 also receives recirculated air from the aircraft cabin at inlet 40 , directing it radially to mix with the process flow air, and then go through outlet 30 to be routed to aircraft cabin as mixed air. Because the air coming out of turbine 20 is subfreezing, and can sometimes contain ice and snow, it has the propensity to clog condenser 26 at inlet to condenser 26 from mixer 24 . This blockage can impede airflow in machine 10 , resulting in machine 10 providing less than acceptable airflow to the aircraft cabin. The insertion of recirculation air (which is warmer air from the cabin) into recirculation air mixer 24 warms overall air temperature, preventing clogging of airflow. Past systems included separate mixing and condenser systems. Past mixing systems typically brought all flow in radially, resulting in the need for additional mixing space to get desired mixing results. This resulted in air conditioning machines which were 52 inches (11 mm) in length or more. By combining condenser 26 and recirculation air mixer 24 into one piece, and mixing air radially and axially, air conditioning machine 10 is able to provide air to the aircraft cabin using much less space. Air conditioning machine 10 is about 42 inches (1067 mm) in length, reducing the length of air conditioning machine 10 by about 20% compared to previous air conditioning machines. Weight of the overall machine is also reduced, saving money and space. FIG. 2A shows a perspective view of condenser 26 and recirculation air mixer 24 , and FIG. 2B shows a perspective view of recirculation air mixer 24 . FIGS. 2A-2B include condenser 26 with hot inlet 36 , hot outlet 38 ; recirculation air mixer 24 with recirculation air inlet 40 , cold air inlet 42 , plenum 44 , annulus 46 and injectors 48 . Condenser 26 and recirculation air mixer 24 can be cast from aluminum, or and other any other metals that can withstand operating temperatures and stresses. Alternatively, they could be molded from carbon fiber, or suitable plastics. Condenser 26 and recirculation air mixer 24 can be welded or bolted together. Recirculation air mixer 24 includes plenum 44 , which is generally an expanding rectangular shape, growing symmetrically in size from the cold inlet until it connects with the condenser. Around plenum 44 , there is an annulus 46 , which connects to recirculation air inlet 40 and injectors 48 . Inlet 40 receives recirculation air from the cabin and delivers it to annulus 46 . Injectors 48 are located on each side of plenum 44 , to inject air flowing in annulus 46 radially into plenum 44 . Airflow from turbine 20 enters plenum 44 axially. In addition to injecting the recirculation air in at least a radial direction from annulus 46 into plenum 44 , the plurality of injectors 48 can also inject air axially. Condenser 26 includes a chamber which receives process air flow from secondary heat exchanger through inlet 36 and condenses air flow by lowering the temperature of process flow air through subjecting it to a subfreezing air flow from turbine 20 (see FIGS. 1A-1B ). This causes vapor in the process air flow to condense, and any liquid is contained in water collector 28 . As mentioned above, due to the cold temperatures and ice and snow mixed in air flow coming from turbine 20 , inlet from mixer 24 to condenser 26 can freeze over, blocking air flow through air conditioning machine 10 . Recirculation air mixer 24 helps to combat this by injecting warmer recirculation air radially and axially through injectors 48 . This radial injection of warm air through injectors 48 promotes quick mixing with the cold air flowing axially through inlet 42 (from turbine 20 ). The quick mixing warms the temperature of air through the system to prevent ice buildup, and radial injectors 48 directs some warm air flow directly at inlet 36 . This helps to prevent freezing on the face of heat exchanger 14 , where the ice build-up commonly occurs. The teardrop shape of injectors 48 also promotes mixing to bring process flow air to a suitable temperature (in a smaller amount of space) for flowing through outlet 30 to the cabin. Combining condenser 26 with recirculation air mixer 24 (with radial injectors) allows for a smaller overall air conditioning machine 10 , while preventing ice build ups which impeded flow through machine 10 in past systems. Radial teardrop shaped injectors 48 promote better mixing in a smaller amount of space. Radial injectors 48 also promote the prevention of ice buildup at inlet of condenser 26 by directing some of warm recirculation air directly towards inlet. Combining condenser 26 with mixer 24 reduces the number of parts associated with air conditioning machine 10 , which reduces the weight and volume required as compared to past system. While recirculation air mixer 24 is shown in the embodiment above to include four teardrop shaped injectors 48 , more or fewer injectors could be used. The shape of injectors 48 could also be varied to promote better mixing and prevent ice buildup. While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
An apparatus for use with an aircraft air conditioning machine to provide conditioned air to an aircraft cabin includes a recirculation air mixer to mix recirculation air and cold air from a turbine in the air conditioning machine as mixed air, the recirculation air mixer including a cold inlet, a plenum, a recirculation air inlet connected to an annulus and a plurality of injectors for injecting the recirculation air from the annulus into the plenum; and a condenser connected to the recirculation air mixer, the condenser including an inlet to receive air from a heat exchanger, a chamber where air from the recirculation air mixer enters to condense the air received through the inlet from the heat exchanger, an outlet for transferring the condensed air to the turbine, and an outlet for transferring conditioned air to the aircraft cabin.
1
BACKGROUND OF THE INVENTION This invention relates to an automatic spike driver for driving spikes through holes in rail tie plates to secure rails to rail ties. A tie plate is a channelled plate which rests on a wooden tie and which receives a rail. The tie plate has two holes on each side but normally spikes are driven through only one hole on each side into the tie, the head of the spike bearing against or being slightly spaced from the rail to ensure the rail, tie plate and tie are all secured together. A problem in driving the spikes automatically is that the holes must be accurately located automatically and a spike setter and driver head positioned so that the spikes can be driven accurately through the holes. Another problem is that the spikes have to be conveyed to the drive head in the correct orientation with respect to the rail. U.S. Pat. No. 3,753,404 to Bryan discloses a spike driver in which rail locators are swung inwardly by an operating cylinder until they engage the rail and these establish a reference for the holes in the tie plate in the X-direction, i.e., in the direction laterally of the rails. The Bryan device then sweeps in the Y direction, i.e., along the rail until a hole is detected at which point a spike is driven by a drive head through the hole into the tie. One problem with the prior device is that it is not easy to envisage how the device would cope with different thicknesses of rails as there is no disclosure as to what causes the operating cylinder to stop extending and one must assume that the piston continues to the end of its stroke. Moreover the angle at which a spike is driven would vary with different thicknesses of rail thus limiting the use of the prior machine. Another problem of the earlier device is that it uses a flexible tube system to convey spikes from a hopper directly to the drive head and so the geometry of this guide tube changes according to the distance the drive head moves in the X and Y directions. Such a variable geometry arrangement is likely, in practice, to give rise to spike feed, and particularly, spike orientation problems. SUMMARY OF THE INVENTION The above mentioned problems are obviated or mitigated by the present invention in which spikes are received at a fixed location in a spike setter and transferred laterally to a drive head the position of which will vary according to rail thickness using a mechanism which ensures that under all circumstances the spike is set exactly under the drive head and the spike setter, hole feeler and spike head are positioned the correct distance from the rail to align with the plate holes. Thus, according to a broad aspect, the present invention provides in a spike driving system for driving spikes through holes in rail tie plates to secure rails to ties, a hole locating mechanism comprising a first member carrying a hole sensing device, means for moving the hole sensing device laterally towards a rail a fixed distance, stop means associated with the hole sensing device and arranged to engage the rail on operation of the moving means to position the hole locating device a predetermined distance from the rail as determined by the stop and corresponding to the distance of the tie plate holes from the rail, the member being movable laterally away from the rail on engagement by the stop means on the rail to take up excess travel of the moving means. According to another aspect of the invention, there is provided a spike driving device for driving spikes through holes in rail tie plates to secure rails to ties, the device comprising a mounting member carrying spike holding means and spike driving means, means for moving the spike holding means laterally towards a rail a fixed distance, stop means associated with the spike holding means and arranged to engage the rail on operation of the moving means to position the spike holder a predetermined distance from the rail, the mounting member being movable laterally away from the rail on engagement by the stop means on the rail to take up excess travel of the moving means. According to yet another aspect a spike driving system comprises a main frame, a work frame carrying a spike driving head, a spike holder, means for moving the spike holder to a position remote from the driving head to a position below the driving head for driving of a spike held in the holder, and a spike guide tube having one end located adjacent the top of the holder and another end located upwardly of the first end, a spike conveyor mounted on the main frame and including an indexing and spike gripping mechanism, means for moving the work frame between a "down" position and an "up" position in which the upper end of the tube is adjacent the spike gripping mechanism, and means for releasing the spike gripping mechanism to deliver a spike therefrom to the spike holder. In the system of the present invention the geometry of the total spike feed path is fixed irrespective of X or Y movement. This is effected by mounting a main fixed geometry portion of the spike conveying and orientation system on a main frame of the machine and providing a guide tube which conveys the spikes from the main portion of the spike conveying and orientation system always at the same angle and orientation to the spike setter. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in greater detail with reference to the accompanying drawings, in which: FIG. 1 is a side view of a rail vehicle embodying the spike driver of the invention; FIG. 2 is an enlarged top view showing a portion of a chain conveyor of the spike driver and a spike gripper mechanism; FIG. 3 is a side view of the structure of FIG. 2; FIGS. 4 and 4a are two enlarged views showing a detail of a spike guide tube of the spike driver; FIG. 5 is an enlarged fragmentary view looking from the rear of the spike driver, i.e., from the right in FIG. 1, and showing a system of frames providing movement in three mutually perpendicular directions; FIGS. 6 and 7 are views similar to FIG. 5 but showing the frames at two successive stages in the operation of the spike driver; FIG. 8 is an enlarged side view, i.e., looking from the left in FIGS. 5-7, of the frame system of FIG. 5; FIG. 9 is an enlarged fragmentary view looking down on the frame system of FIG. 8; FIG. 10 is an enlarged perspective view of a reference mechanism forming part of the spike driver; FIGS. 11-13 are 3 diagrammatic views showing the mechanism of FIG. 10 at successive stages of its operation; FIG. 14 is an enlarged fragmentary view looking in the same direction as FIG. 5 and showing in detail the shape and configuration of the spike guide tube, setter and drive head; and FIG. 15 is a greatly enlarged view looking from right to left of FIG. 14 and showing in detail the configuration of the setter assembly. DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIG. 1, a spike driver 10 is formed as a self propelled rail car which travels along rails 11 already positioned in tie plates laid on transverse wooden ties. In the drawing only one tie 12 and one tie plate 13 are shown. The structure of the spike driver will be described with reference to the rail shown in FIG. 1, it being understood that the structure for the other rail is identical. The spike driver 10 has a main hopper 14 carrying a load of spikes 15 which will be used for securing the rails 11 to the ties 12 through the agency of the tie plates 13. The hopper 14 is provided with a pusher 18 connected to a drive chain 19 which drives the pusher towards the rear (right hand side as seen in FIG. 1) of the spike driver 10 to push spikes over the rear edge of the main hopper 14 into a further hopper 20 the floor of which is formed as a turntable 21 which serves to disentangle the spikes and spread them individually around the periphery of the hopper 20. Mutual separation of the spikes in this way is essential to proper operation of the spike pick-up mechanism described below. Another feature of the hopper 20 is that the turntable 21 may be forced down under the weight of the spikes against the action of a spring to open a limit switch to de-energize the chain and pusher 18 to ensure an optimum load of spikes in the hopper 20. The hopper 20 is generally cylindrical and is open at the top and has an access door 24 formed by removing a portion of the peripheral wall 25 at a location towards the rear and outside of the spike driver 10. Mounted adjacent the door 24 is a spike pick-up mechanism. The mechanism comprises essentially a pivotable articulated arm 26 carrying an electromagnet 27 and movable under the action of a pneumatic cylinder 28 to swing the electromagnet into hopper 20 to "grasp" a spike and back out of the hopper 20 and over a sloping guide 30. Limit switches (not shown) control the operation of the cylinder 28 and energization and de-energization of the electromagnet 27 so that the spike adhered to the magnet 27 is swung around and dropped into the guide 30. The guide 30 forms a portion of a spike orientation system generally designated as 31. The spike orientation system is well known in the art and will not, therefore, be described in detail. Suffice it to say that it serves to ensure that all the spikes dropped by the pick-up mechanism into the guide 30 are oriented with their heads in the same direction. This is important because the spike heads are not perfectly circular but have a radially projecting portion which is adapted to overlie the base of the rail. As the spikes leave the orientation system 31, they pass along a pair of guide rails 33 by gravity assisted by vibrators attached to the rails to ensure positive feed with the spike shanks lying vertically, the guide rails being provided with a gate shown schematically at 34 which operates to direct the spikes alternately to two storage locations 35, one located inwardly of the rail 11 and the other located outwardly of the rail. There are two storage locations 35 because spikes have to be driven in at both sides of each rail. When the storage locations are full, a limit switch shuts off the orientation system 31, the storage locations being refilled when their levels have dropped below a predetermined value. The following description will be directed to the structure associated with the driving of spikes at the outside of the rail shown, it being understood that there is identical structure associated with the inside of the rail shown. A pair of guide rails 40 extends upwardly and forwardly from the bottom of each storage locations 35 and a drive chain 41, entrained on sprockets 42, is mounted with an upper chain run adjacent the guide rails 40. As best seen in FIG. 2 spaced rods 44 extend transversely from the chain 41 under the guide rails 40. Each rod 44 engages the shank of the lowest spike in the storage location 35 as the chain 41 is driven in a counterclockwise direction to drive that spike upwardly and forwardly to the most forward position of the guide rails 40. The spike orientation system 31 supplies spikes to the storage locations 35 at a higher speed then they are taken from the storage locations 35 by the drive chain 41. Thus there is always a spike ready for pick up by the drive chain, and synchronism of the drive chain 41 and orientation system 31 is rendered unnecesary. Movement of the chain is intermittent and is effected by means of a pneumatic cylinder 46 the stroke of which is equal to the distance between the rods 44 so that as the cylinder 46 is actuated a fresh spike is recieved on the guide rails 40, the spikes already on the rails 40 are indexed forwardly and the leading spike is advanced into a spike gripper mechanism 47 which will be described with particular reference to FIGS. 2 and 3. The spike gripper mechanism 47 comprises two short rods 48 mounted in close alignment with the foremost end of the guide rails 40. One or both of the rods may be magnetic. The rods are retractable through a back plate 49 by means of a pneumatic cylinder 50. When the chain 41 is indexed the leading spike is propelled by the associated rod 44 forwardly from the position indicated as L1 in FIG. 3, the momentum of the spike being sufficient to carry it from the guide rails 40 on to the rods 48 of the gripper mechanism 47. Swinging of the spike is reduced on engagement thereof with the back plate 49 and swinging is further reduced by the clamping action of the magnetic rod (or rods) 48 thus ensuring that the spike quickly regains a vertical disposition. The rods 48 are timed to retract under the action of cylinder 50 after a guide tube 53 has been moved vertically upwards in registry with the shank of the spike gripped in the L2 position. The upper end of guide tube 53 is particularly configured as most clearly seen in FIGS. 4 and 4a virtually to surround the entire spike including the head. This ensures that the spike will drop on retraction of the rods 48 in correct alignment and with a minimum of lateral wobble. The purpose of the tube 53 is to guide the spikes 15 successively to a spike setter 57 which, in turn, is adapted to position or "set" successive spikes under a drive head 58, the setter 57 and drive head 58 being clearly shown in FIG. 5. The guide tube 53, setter 57 and drive head 58 are located in a common vertical plane, each being dispoed at the same small angle to the vertical. The setter 57 and drive head 58 are supported on a system of frames permitting vertical, lateral (with respect to the rails 11) and longitudinal movement and this system of frames will be described with particular reference to FIG. 1 and FIGS. 5-9. A work frame 60 is vertically movable on two guide beams 61. The work frame 60 is generally H-shaped as seen in FIG. 8 comprising two vertical sleeves 62 received on the beams 61 and a cross member 63. As seen most clearly in FIG. 9 the work frame 60 also carries two spaced rods 64 slidably supporting a Y-frame 65. The work frame 60 is movable vertically under the action of a pneumatic cylinder 68 connected between the cross member 63 and a point on the main frame 69 of the machine. The Y-frame 65 is capable of limited motion in the Y direction (i.e., along the track) relative to the work frame by sliding on the rods 64 under the action of a pneumatic cylinder 70, four bushings 71 providing the sliding interconnection with the rods 64. The main portion of the Y-frame 65 is suspended below the rods 66 and has two pairs of depending mounting portions 74 supporting two parallel spaced rods 75 extending horizontally beneath the rods 64 and perpendicularly with respect to the rods 64, i.e., rods 75 extend laterally with respect to the rail 11 which is known as the X-direction. Carried on the Y frame 65 is an X-frame 77 which by virtue of bushings 78 slidably mounted on the rods 75 is capable of limited sliding movement in the X-direction relative to the Y-frame 65. A spring 79 extending between one of the mounting portions 74 (see FIGS. 5-7) and an appropriate bushing 78 biases the X-frame inwardly in the direction of the rail 11 to a position defined by a stop 80 mounted on the rod 75. The X-frame is suspended by the bushings 78 and comprises essentially two spaced plates 82 weled together to form a channel-like configuration on which are mounted the tube 53, the setter 57 and the drive head 58. The setter 57 is connected to the lower end of an outermost leg portion 83 of the X-frame and the drive head 58 is mounted on the lower end of an inner leg portion 84. The tube 53 is mounted on a central portion 85 of the X-frame. As best seen in FIG. 8, a pneumatic cylinder 86 is mounted vertically between the plates 82 on a tie-piece 87. The piston 88 is tipped with rubber or other high friction material and is adapted on extension to cause the rubber tip to engage with the underside 89 of the Y-frame 65. The setter 57 is actually mounted on a plate 90 carried on the end of a piston 91 of a pneumatic cylinder 92 mounted on the outer leg 83. Mounted also on the plate 90 on either side of the setter is a hole feeler 94 and an adjustable stop 95 (see FIGS. 14 and 15). The setter 57 is formed as a generally U-shaped open channel, the side walls 97 of which have two opposed holes through which project looped portions 98 of cantilever springs 99 attached to the outsides of walls 97. The base 101 of the setter has a circular magnetic portion 102 located about one third of the way up from the bottom of the setter. At the top of the setter is a spring loaded plate 103 which is pivotally mounted on the lower end of the guide tube 53. The plate 103 has a bent retaining finger 104 which projects partly into the channel of the setter. A U-shaped stop plate 105 is mounted on the inner end of the cylinder 92 so that it is aligned with the opening at the bottom of the guide tube 53. The U of plate 105 is wider than the shanks of the spikes but narrower than the heads of the spikes. The side walls 97 of the setter are stepped at 106 so that the lowest portions 107 of the walls project less than the upper portions 108. The hole feeler 94 comprises a mechanical finger 112 which is adapted to ride along a tie plate and when it enters a hole to extend slightly then immediately retract to operate a switch in the feeler to indicate the presence of a hole. The stop 95 is formed as a screw threaded member 113 mounted in a vertical slot 114 in a plate 115 by two nuts 116, one at each face of the plate. Clearly, the member 113 may be adjusted in terms of its height and its length of projection by adjusting the nuts. The free end of the member 113 is intended to engage the "head" 11a of the rail 11 and this establishes the minimum spacing of the setter from the rail. To reduce friction a roller may be mounted to the free end of the member for engagement with the head of the rail. The length the member 113 projects must be chosen to ensure that a spike in the setter and also the mechanical finger 112 of the hole feeler are positioned the same distance from the rail head as the tie plate holes and the height of member 113 must be chosen to ensure engagement with the "head" of the rail. The adjustability feature permits use with different sizes of rails. Also attached to the work frame 60 is a pair of vertical spaced legs 117 ending in adjustable feet 118. The height of the feet is adjustable to provide for different heights of rail so as to maintain the setter at a predetermined distance above the tie plate which distance is seen in FIGS. 5, 6 and 7. The sequence of steps involving the movement of the various frames will now be described. With the work frame 60 in the up position, the upper end of the guide tube 53 surrounds a spike held in the spike gripper mechanism 47. A limit switch (not shown) operates to retract the rods 48 dropping the spike down the tube 53. The spike is carried by gravity and in the correct orientation into the setter 57 where it is stopped by engagement of the spike head with the stop plate 105. The springs 99 ensure the spike is held centrally in the setter and the finger 104 of plate 103 prevents the spike from "jumping" laterally out of the open end of the setter 53. The work frame 60 is then lowered until the feet 118 rest on the rail and the various frames 60, 65 and 77 assume the positions shown in FIG. 5. The feet provide a stable base from which the spike driving may be performed. The cylinder 92 is then actuated, extending piston 91 until the stop 95 engages the rail 11 which is the position shown in FIG. 6. The piston is not yet in its full stroke position but the setter is the correct distance from the rail 11 as determined by the stop 95. It is noted that as the setter 57 is moved out of alignment with the guide tube 53, the plate 103 is pivoted forwardly and upwardly free of the forward face of the setter 57 allowing the setter to push the spike held in the setter out of the open end of the U in the stop plate 105, the magnet 102 serving to hold the spike in the setter from this point on. As extension continues to the full stroke position, the piston 91 is unable to move any further to the right and so the cylinder 92 moves to the left. Because the cylinder 92 is mounted on the X-frame 77, the X-frame moves to the left against the action of the spring 79 until the full stroke position is reached. In this position, shown in FIG. 7, the drive head 58 is aligned above the setter 57. It is clear from the above discussion that, in the retracted position of the piston 91, the setter 57 is a predetermined lateral distance from the drive head 58, which predetermined lateral distance is equal to the stroke of the piston so that when the piston is fully extended to its fixed stroke position, the spike setter and drive head are correctly aligned. The position of the stop 80 is not critical except that it should not be located so far to the left as seen in FIGS. 5-7 as to prevent the stop 95 engaging the rail in the full stroke position of piston 91. The provision of the spring connection between X-frame 77 and the Y-frame 65 permits excess travel of the fixed stroke piston to be taken up. This arrangement ensures that the spike setter 57 is always aligned under the drive head 58 no matter what the thickness of the rail head. The Y-frame 65 then sweeps in the Y-direction under the action of pneumatic cylinder 70 (FIG. 9) which is initiated by a limit switch (not shown) detecting full stroke of the piston 91. The finger 112 of the hole feeler 94 traces along the upper surface of the tie plate 13 until it finds a hole in the tie plate at which point it extends into the hole and immediately retracts operating a switch in the hole feeler 94 to indicate the presence of the hole. This operates a Y-reference mechanism described below which references the drive head 58 and setter 57 to the hole position. The Y-frame continues its sweep until the drive head 58 and setter 57 are aligned with the hole as determined by the Y-reference mechanism. With the Y-frame stopped in this position, the drive head 58 is operated and simultaneously the piston 88 is extended to engage the underside of the Y-frame. The head 58 drives the spike in the setter (which is held only by the magnet 102) down through the tie plate hole and into the tie, the engagement of the piston 88 with the Y-frame serving to lock the X-frame relative to the Y frame to prevent any tendency for the X-frame to move laterally under the force of the drive head 58. The Y-reference mechanism, referred to above, is generally referenced 120 in FIGS. 10-13. Referring firstly to FIG. 10, the mechanism 120 includes a slim rod 121 which extends parallel to and just above one of the rods 64 along which the Y-frame 65 slides. The rod 121 is received loosely in two holes 123 provided respectively in the bushings 71 of the Y-frame 65. The rod 121 has a head 125 which limits movement of the rod 121 to the right as seen in FIG. 10. A very strong tension spring 127 extends between a screw 128 carried on top of one of the bushings 71 and a plate 129 rigidly mounted on the rod 121. The spring 127 urges the rod 121 to its extreme right hand position, as seen in FIG. 10, in which the head 125 bears against the left hand bushing 71. The right hand end portion of the rod 121 is seen to protrude beyond the right hand bushing. Approximately centrally, the rod 121 carries a "tongs" arrangement 131 which includes two generally triangular members 132 and 138 extending outwardly from diametrically opposed locations on the rod 121. Both members 132 and 133 are fixed in the longitudinal direction of the rod 121 by suitable locking members 126 but are free to pivot circumferentially with respect to the rod 121 at least over a small arc. As can be seen the member 132 is formed of two spaced plates and the member 133 as a single plate extending from a point between the plates of member 132. The lower end of each member 132 and 133 carries a similar arcuate gripping pad 135 spaced closely adjacent the circumferential surface of the rod 64 along which the Y-frame slides. The shape of the pads 135 conforms to that of the rod 64. A pneumatic cylinder 136 is mounted between the upper ends of the members 132 and 133, pivotal connections 137 being provided at the interconnections of the cylinder and the member 132 and of the piston 138 and the member 133. It should be appreciated that as the piston 138 moves out of the cylinder 136 the tops of the members 132 and 133 are pushed apart, the members 132 and 133 rotating in opposite senses until the pads 135 grip the rod 64. The rod 121 also carries an abutment 140 serving as an actuator for a limit switch 141 mounted on the left hand bush 71. Operation of the Y-reference mechanism 120 will now be described with reference to FIG. 11-13 in which the setter 57, head 58 and hole feeler 94 are shown schematically to indicate their respective positions corresponding to different positions of the Y-reference mechanism. In FIG. 11, the setter piston 91 has been fully extended so that the X-frame 77 is in the position indicated in FIG. 7, and the Y-frame 65 is about to begin its sweep (to the right in FIGS. 11-13). As the Y-frame moves the feeler 94 engages a hole in the tie plate 13 a little later as shown in FIG. 12. Because of the stiffness of the spring 127, the Y-reference mechanism 120 moves along with the Y-frame 65 without relative movement. As indicated above, the extension and retraction of the finger 112 operates a microswitch. This causes actuation of the cylinder 136 which immediately causes clamping of the gripping pads 135 on the rod 64. The rod 121 is now fixed to the rod 64 and as the Y-frame 65 continues its rightward travel the spring 127 is extended as the limit switch 141 approaches the abutment 140 on the now stationary rod 121 until the position shown in FIG. 13 is reached. In the FIG. 13 position the switch 141 has just been actuated by the abutment 140 causing de-energization of the cylinder 70 (FIG. 9) driving the Y-frame 65. The Y-frame is now stopped with the setter 57 and drive head 58 aligned over the tie plate hole and the drive head 58 is actuated to drive the spike in the setter into the hole at a small angle to the vertical. The shape and configuration of the setter 57, particularly the open longitudinal face and the small angle at which the setter is disposed, enable the setter to be positioned closely and accurately relative to the hole even at the location of a rail joint bar 118 as seen in FIG. 14. There is one other aspect of the machine which has not yet been described and this is the means for securing the tie 12 against the force of the drive head 58 as the spike is being rammed through the hole in the tie plate and into the tie. With reference to FIG. 1 this "means" comprises a pair of tie nippers 144 which may be hydraulically moved towards and away from each other on a rod 145. The nippers 144 may also be lowered and raised by means of a hydraulic cylinder 147. In operation, once the feet 118 of the work frame 160 contact the rail the nippers 144 are lowered one on each side of a tie 12 into the ballast under the tie. When the nippers reach a predetermined depth they then are forced together into contact with the sides of the tie. The nippers 144 are actuated in parallel hydraulically so that the tie will be urged to a position in the vicinity of the setter and attached hole feeler. In the event the tie is immobile in the ballast the closing of the nippers 144 will cause movement of the work frame to assume the correct relative positions of the hole feeler and tie. While the tie is being squeezed by the nippers 144, the nippers are raised, free end portions 148 of the nippers engaging the index side of the tie and holding the tie and tie plate tight against the rail. The reaction of this lift force is transferred back through the work frame feet 118 to the rail. The nippers 144 hold the tie throughout the whole spike driving cycle after which they are retracted in a sequence opposite to the extension sequence except that the nippers 144 are forced downwardly for an instant prior to being moved outwardly to release the tie. The complete operation of the spike driver will be summarized in the following sequence of events. 1. The spike driver car is positioned on the track such that a tie 12 is located generally centrally below the nippers 144. 2. The work frame 60 is lowered until the feet 118 engage the top of the rail. 3. The nippers 144 are lowered, squeezed together and raised under the tie. 4. The setter 57 is extended in the X-direction to a location between the holes in a tie plate 13. 5. The Y-frame 65 sweeps in the Y-direction towards one of the holes in the tie plate 13. 6. The hole feeler 94 senses the hole and operates the Y-reference mechanism 120. 7. The Y-reference mechanism stops the Y-sweep with the setter 57 and drive head 58 aligned over the hole. 8. The drive head 58 drives the spike from the setter through the hole and into the tie and simultaneously the piston 88 is extended to lock X-frame 77 and Y-frame 65 together. 9. The drive head 58 retracts and the piston 88 is simultaneously retracted. 10. The indexing cylinder 46 operates to index the spikes on the conveyor chain 41 and propel the leading spike into the gripper mechanism 47. 11. The nippers 144 are then moved downwardly and outwardly. 12. The setter 57 is retracted away from the rail 11. 13. The nippers 144 are raised. 14. The Y-frame 65 sweeps back to the start position. 15. The work frame 60 is raised, the guide tube 53 registering with the spike held in the gripper mechanism 47. 16. The gripper mechanism 47 releases the spike which is caught in the setter 57. 17. The spike driver car is moved to the next tie 12 where the operation is repeated.
A spike driving machine is disclosed in which a hole sensing device and spike holder are driven in toward a rail under the action of a fixed stroke piston and cylinder until a stop engages the rail. The stop has been previously adjusted to line up the hole sensing device and spike holder the correct lateral distance for engagement with the tie plate holes. Excess travel of the piston and cylinder is taken up by providing a flexible connection between an X-frame carrying the hole sensing device, the spike holder and a drive head and a Y-frame which is fixed in the lateral direction. The stroke is chosen to align the spike holder under the drive head. Thus, the arrangement can be used for rails of differing thickness simply by adjusting the stop appropriately.
4
FIELD OF THE INVENTION The invention relates to a marker and a method of using the marker in a system for detecting the marker, and the activity state of the marker to prevent unauthorized removal of objects having the marker attached thereto, or internally contained. DESCRIPTION OF THE PRIOR ART There are in existence several systems for detecting or preventing the theft of articles of value. One of these described in U.S. Pat. No. 3,754,226, granted to E. R. Fearon, Aug. 21, 1973 entitled "Open-Strip Ferromagnetic Marker And System For Using Same," describes an improved marker and system. This marker, when secured to an object, enables detection of the presence of the object when the object is in an interrogation zone, such as a doorway, when the zone has a magnetic field varying at a pre-determined fundamental frequency. This marker utilizes an elongated ferromagnetic marker of low coercivity capable of generating a detectable signal containing harmonics of the fundamental frequency when placed in the zone. An improvement to this invention described in U.S. Pat. No. 3,747,086, granted to Glen Peterson, July 17, 1973, entitled "Deactivatable Ferromagnetic Marker For Detection Of Objects Having Marker Secured Thereto And Method And System Of Using Same," adds an element of high coercivity to the element of low coercivity whereby the magnetized, or unmagnetized, state of the high coercivity element controls the ability of the low coercivity element to generate and radiate harmonics of the interrogating signal. This improvement makes it possible to determine, with considerable precision, whether or not the goods being passed, or carried, through the interrogation zone are being properly removed or whether the passage is illicit. A somewhat earlier system for detecting or preventing the theft of articles corresponds with U.S. Pat. No. 3,292,080, granted to E. M. Trikilis, Dec. 13, 1966, makes use of a magnetometer in the interrogation zone and utilizes a magnetized object which identifies the article unless check out procedure has removed the magnetism from the object. French Pat. No. 763,681, issued to Pierre Arthur Picard, discloses a remote detection system which employs dynamic magnetic phenoment to detect the presence of an object. The system of Picard, which is fundamental to most of the useful ferromagnetic systems presently in use, is based upon the discovery that a piece of metal subjected to a sinusoidally varied magnetic field produces in a pair of balanced pickup coils in the vicinity of the applied field an induced voltage characteristic of the metal. The Picard patent discloses that high permeability metals produce an induced voltage including high order harmonics of the sinusoidal field. Additionally, in the area of ferromagnetic markers, the patent issued to Robert E. Fearon Dec. 22, 1971, U.S. Pat. No. 3,631,442; the patent issued to James T. Elder and Donald A. Wright May 23, 1972, U.S. Pat. No. 3,665,449; and the patent issued to James T. Elder Oct. 9, 1973, U.S. Pat. No. 3,765,007 make use of some of the foregoing and related phenomena. All of the foregoing systems have severe difficulties of one kind or another. The Trikilis system requires a rather large piece of ferromagnetic material for the marking of the merchandise, otherwise ambient variations in the magnetic field are greater than the changes caused by the Trikilis marker. The Picard system does not provide a means of deactivating the marker, nor does it provide a means of sufficient sensitivity to uniquely identify particular marker construction as opposed to other ferromagnetic materials. While the combined systems of E. R. Fearon and Glen Peterson, above referenced, together provide great sensitivity and a means of deactivating the marker, experience shows that additional sensitivity would be useful, and the deactivation means is one a half-way measure; e.g., it depends upon whether or not one or more of the elements of the marker are magnetized or demagnetized. Similar defects can be found in the methods used by J. T. Elder and Donald A. Wright. SUMMARY OF THE INVENTION The most definite states of a piece of ferromagnetic material are not those pertaining to whether it is magnetized or demagnetized. The magnetized state is quite certain but the demagnetized state is variable and uncertain because it is the nature of all ferromagnetic materials to become magnetized to one degree or another, and this ability is greatly influenced by such variables as ambient temperature, position in the earth's magnetic field, and the nature of neighboring objects. Computer memories, for example, do not rely on the magnetized and de-magnetized states to provide the 0,1 of bit storage: the de-magnetized state is far too uncertain. Accordingly, computer bit storage is based upon the two saturated conditions of the hysteresis loop of any piece of suitable ferromagnetic material. A "0" is when the material is flipped in an arbitrarily chosen saturated condition, and a "1" is when the material is flipped into the opposite saturated condition. It is fortunate for computers that conductors can be used to thread memory cores and thereby provide a sense of direction; alternatively, the direction of rotation of disc, drum and film ferromagnetic memories can be used to provide the sense. No such simple means is, however, available to the methods and means of anti-pilferage systems. Since, for obvious reasons, non-contact systems are greatly preferred, we can't use wires to determine the sense of magnetism in a marker, and since a package which has a magnetic marker inside can be carried through the door of an interrogation zone in any direction and orientation that pleases the customer, the direction of motion of the package to determine "sense" is not available either. Despite these obstacles, the precision of control offered by the two magnetized states of ferromagnetic materials, as compared with the mere magnetized and de-magnetized states, makes it highly desirable to find and provide methods and means whereby the two magnetized states might be used to determine the status of packages of goods. Such provision is the entire object and purpose of this invention. The magnetic markers are provided in pairs, and in the preferred embodiments of the invention, the two members of each pair are made as identical in size, shape, weight and material composition as it is possible to make them. In every instance of application, both members of a pair are magnetized and the two states are determined by whether the pair members are magnetized "aiding" or "opposing" each other. In an interrogation zone where both static and dynamic fields can be made available, the response of the markers will be quite different when magnetized in opposition than what it is when the markers are magnetized to aid each other. Moreover, as will be shown, the conditions of opposition and aiding of the marker pairs can be switched at two or more stages of any check-out system, by the method and means of this invention, and in this way the licit and illicit movement of goods determined with great precision. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a geometric arrangement of ferromagnetic marker pair wherein the pair members are magnetized in opposition. FIG. 2 shows the marker pair of FIG. 1 with the pair members magnetized aiding. FIG. 3, in three views A, B, and C, shows another geometric arrangement of marker pairs wherein the pair members are magnetized in opposition. FIGS. 3A and 3C are plan views of the arrangement, and FIG. 3B is an edge view. FIG. 4, with corresponding A, B, and C views, shows the geometric arrangement of FIG. 3 with the parker pair magnetized aiding. FIG. 5 shows a third geometric arrangement of magnetic marker pairs wherein the pair members are magnetized in opposition. FIG. 6 shows the marker pair of FIG. 5 with the pair members magnetized aiding. While many other geometric arrangements of ferromagnetic marker pairs may be possible, the three geometric arrangements illustrated by FIGS. 1 through 6 are the basic arrangements and all others will be derivatives thereof. It is obvious, for example, that the marker pairs instead of being in straight-line, plane relationships can be arranged at angles with each other if any justifiable reasons can be found for such arrangements. The illustrations here provided are considered all that are necessary to adequately define the invention. FIG. 7 is a drawing showing the magnetic field produced by the marker pair of FIG. 1. FIG. 8 is a drawing showing the magnetic field produced by the marker pair of FIG. 2. FIG. 9 is a drawing showing the magnetic field produced by the marker pair of FIG. 3. FIG. 10 is a drawing showing the magnetic field produced by the marker pair of FIG. 4. FIG. 11 is a drawing showing the magnetic field produced by the marker pair of FIG. 6. FIG. 12 is a drawing showing the magnetic field produced by the marker pair of FIG. 5. FIG. 13 shows typical hysteresis loops of possible ferromagnetic marker pairs, whereby some of the magnetic fundamentals are explained. FIG. 14 is a composite diagram of four hysteresis loops whereby the operation of the present invention is further explained. FIG. 15 is a diagram showing the functional arrangement of the system in the interrogation zone. FIGS. 16, 17, 18 and 19 are graphs of some of the wave forms that can be used in practicing the invention. FIG. 20 is a drawing, in partial cross-section, showing the means provided to magnetize the marker pair of FIG. 1. FIG. 21 is a drawing showing the means provided to magnetize the marker pair of FIG. 2, or flip the pair of FIG. 1 to the magnetized state of FIG. 2. FIG. 22 is a drawing in perspective view showing an alternative means provided to magnetize marker pairs having the geometry of FIG. 1, that is also adapted to the mass production of such marker pairs. FIG. 23 is a drawing in perspective view showing an alternative means provided to magnetize marker pairs of the configuration of FIG. 2. FIG. 24 is a drawing in plan view showing the application of the invention to currency. FIG. 25 is a schematic circuit diagram showing the preferred form of wave detector used in the analysis of wave shapes in the practice of this invention. FIG. 26 is a drawing in perspective view showing a preferred form of status-determining, or pair switching coils, used in the system of this invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS I now turn to FIGS. 1 and 2 where a preferred form of ferromagnetic marker is shown. 11 and 12 are two identical pieces of suitable ferromagnetic material which preferably are thin, narrow and long. They are held in position by a suitable non-magnetic body 20, to which they are attached, or in which they are inbedded, and this body can be made from plastic, paper, wood, aluminum, stainless steel, etc. 23 indicates a suitable gap between the adjacent ends of the two strips 11 and 12. initially, the marker is magnetized in the state shown by FIG. 1 with the fields opposing each other as illustrated in FIG. 7. Following payment for, and/or check-out of, the item of goods to which the marker is attached, the goods, with marker attached, is passed through the field of a magnetic system, such as those of FIGS. 21 or 23, and the magnetization of strip 12, FIG. 1, changed to that shown as 13, FIG. 2. The two strips are now magnetized as aiding each other, and since gap 23 is short compared with the length of either 11 or 13, the two strips will act essentially as if they were one long magnet having a field as shown by FIG. 8. In using the apparatus of FIGS. 21 or 23 to flip the magnetization of strip 12 to that of strip 13, it should be noted that a short uni-directional pulse of current is put through coils 114 or 131 in such direction as to drive 11 further into saturation of the polarity shown which direction will flip 12 over into the magnetization of 13, as already stated. The switching apparatus which energizes the magnetizing/demagnetizing coils 114 or 131 will have a suitably rapid turn-on-turn-off characteristic such that the slug of current is not given time to reverse direction, or oscillate, as such currents in coils often want to do. The art of magnet chargers is well developed in this area of action and big fast-switching transistors or SCR's are usually employed for this purpose today. Alternatively, the magnet charging apparatus of U.S. Pat. No. 3,390,310, issued to Glen Peterson June 5, 1968, may be employed. The responses of the markers of FIG. 1 and FIG. 2, when placed in an interrogation field, or door, such as represented by FIG. 15, will be vastly different. For example, if the interrogation field is a sinusoidal field of fundamental frequency, f, the response of the marker of FIG. 1 will be rich in even-ordered harmonics 2f, 4f, 6f, etc., while the response of the marker of FIG. 2 will be rich in odd-numbered harmonics 3f, 5f, 7f, etc. What is more, if the strips are carried length-wise through the interrogation field, or have a sufficiently large component aligned with the axis of the interrogation field, the even-numbered harmonic response of the marker of FIG. 1 will first increase exponentially as the field is approached from a distance, will then begin to decrease as the marker enters the door, will fall rapidly to zero when the marker is exactly centered in the field, will then build to a peak as the marker leaves the doorway on the other side, and thereafter fall off exponentially. Furthermore, the phase of the harmonic response will change at the center of the doorway so that if the signal is analyzed by the coherent detector of FIG. 25, the polarity of the voltage pulse across terminals e and f will reverse at the center of the doorway. On one side of the doorway, the voltage across terminals e and f will be positive while on the other side of the doorway the voltage will be negative. Again, if the marker strips 11 and 12 are made identical to a high degree, the detection system can be tuned to a high degree of balance and given great sensitivity. Thus, the presence of the markers, and the customer carrying the goods containing the marker can be made known a sufficient distance from the doorway to alert personnel. With appropriate arrangements, as interrogation coils hidden in the floor, goods cases, and other non-obvious locations, customers could be suitably monitored over an entire area. No such response issues from the marker configuration of FIG. 2, as issues from FIG. 1 marker configuration. As already noted, the response of the FIG. 2 marker will predominately be fundamental and odd harmonics; furthermore, the response, as the marker moves through an interrogation zone, will build up to a single maximum at the center of the door and fall off exponentially on either side without a change of phase. Thus, the two markers can be identified, not only by their harmonics, but also by the manner of signal build up and decay. One excellent application of this invention, not hitherto used, is to paper money or currency. It is proposed to tag paper money after the manner of FIGS. 1 and 2 so that in a bank, cash register, safe, or armoured truck, the currency would be put in the condition of FIG. 1, or vice-versa, while in general circulation it would be put in the condition of FIG. 2, or vice-versa. While hold-up bandits and burglars could equip themselves with the apparatus of FIGS. 20 through 23, they would scarcely have an opportunity to use it inside a bank or store. While robbers could bring metal boxes with them in which to put the currency so as to shield it from the interrogation field, such metal boxes are the easiest thing in the world to find by an interrogating field; as a matter of fact, we go to considerable trouble to avoid detecting such things. Accordingly, and regardless of what bank or store employees did, or didn't do, regardless of what the hold-up artists did, or didn't do, a burglar alarm could be sounded. The markers in paper money could be in the form of strips as shown in FIGS. 1 and 2, or they could be made part of the pattern of the money itself. Before passing to the other geometric arrangements of the ferromagnetic marker strips of this invention, it should be noted that as long as the two strips of a pair are as identical as it is possible to make them, neither is capable of demagnetizing the other or even of appreciably altering the character of the magnetization thereof. Both must remain in the condition they are put by apparatus external to them. FIGS. 3 and 4 show an arrangement of ferromagnetic marker strips wherein the strips 41, 43 and 44 are placed overlaying each other inside, or on the surfaces of, a nonmagnetic body 30, and with a suitable space, or gap, 33, between them. Again, the only difference between strips 43 and 44 is the direction of magnetization. FIGS. 3A, 3C, 4A and 4C are plan views of the arrangement, while FIGS. 3B and 4B are edge views. The pair of FIG. 3 is magnetized in opposition and will produce the magnetic field pattern of FIG. 9, while the pair of FIG. 4 is magnetized aiding. The magnetization pattern of FIG. 23 can be readily accomplished by placing the tags inside a coil, such as that of FIG. 23, while the pattern of FIG. 4 can be obtained by bringing each tag against the poles of a charger, such as FIG. 22. When this is done, the marker closest to the poles of the charger will act as principal while the marker furthest from the poles of the charger will serve as keeper. If both members of the pair are ferromagnetically identical, they will, following relaxation from the charging pulse, align themselves as shown by FIG. 4 to give essentially no external magnetic field as each keepers the other. When placed in an interrogation field, the configuration of FIG. 3 will respond essentially as if a single magnet was present; i.e., produce the fundamental and odd harmonics predominately. The configuration of FIG. 4, on the other hand, will be essentially clamped magnetically and will not readily give rise to harmonics of any kind: it becomes a magnetic system that is closed to external influences - at least to the extent that the magnetization prevails. In this sense, this marker responds in the same way that my marker does in U.S. Pat. No. 3,747,086 when the member of high coercivity is magnetized and clamps the member of low coercivity. The only difference here is that the two members of the pair are identical and will hold each other clamped at, or near, the opposing points ±B R of remanent magnetization; whereas, in U.S. Pat. No. 3,747,086 the high coercivity member will have fallen beyond B R to some lower de-magnetization point on the hysteresis loop, as +B 1 , FIG. 13, while the low-coercivity member will be held at -B 1 , near B sat for the low coercivity member. FIGS. 5 and 6 show a side-by-side placement of ferromagnetic pair members 61, 63, and 64. 50 is the non-magnetic material which holds the strips in position with a gap, 53, separating them. Again, the only difference between strips 63 and 64 is the direction of magnetization with respect to 61. The N, for north pole, and S, for south pole, of these strips, as well as all previous ones, indicated how the strips are magnetically polarized. Obviously, pairs in FIGS. 1 through 6 can be polarized oppositely to the ways illustrated without departing from the essence of this invention, as: S - N, N - S, with respect to FIG. 1; and S-N, S-N eith respect to FIG. 2., etc. The field patterns of the markers of FIGS. 5 and 6 are given in FIGS. 11 and 12. Depending upon the width of the gap 53, the marker of FIG. 5 will act as if it were a single magnet, or composed of two separated magnets, and this, in turn, will determine the nature and content of the harmonics radiated. Referring again to FIG. 7, the separated field patterns comprised of flux lines 14 and 15 indicate the nature and extent to which the strips 11 and 12 are susceptable to the magnetic field in the interrogation zone and the re-radiation of energy picked up therein. There are, of course, no flux lines in the gap 23 as the two S-poles repel each other. This repelling force keeps the strips trapped at points R and R', FIG. 14, at magnetizations slightly less than B R , the strips forming an open magnetic system. If point R of strip 11, for example, tries to move down the hysteresis loop toward some lower value of flux density and higher MMF, the repelling force of strip 12, at R' will push it back where it belongs. On the other hand, if R tries to move up the hysteresis loop, it would have to gain some energy from somewhere to be able to do this. And if it did somehow gain the necessary energy, the new point would be unstable because there is only one pair of points on the two demagnetization curves, considering leakages and all other magnetic phenomena, where the two strips can rest in harmony. Accordingly, if one strip or the other momentarily gains energy and rises to a different point than where the two strips are in equilibrium, it would be obliged to radiate this energy and fall back to the stable position. Similarly, referring to FIGS. 8, 24 and 25 and 26 point to the flux lines of the field of this system of magnets. The flux lines 25 and 26, across the gap 23, are entirely enclosed and shielded by the external flux lines 24, and this pattern of flux lines describes the susceptibility of this magnetic system to external influences such as those of an interrogation zone. However altered momentarily by the external field, this pattern of flux lines represents the ground state to which the magnetic system must return, all energy different from this which has been received and momentarily stored having to be re-radiated. FIG. 9 shows the magnetic pattern of the strip configuration of FIG. 3, as previously stated. The strips 41 and 43 being held in opposition, there is no flux in the gap 33, and the external flux is indicated by lines 31 and 32. Also, as previously noted, this field pattern is essentially that of a single magnet when the gap 33 is small compared with the other dimensions of the system. The susceptibility of the system to external influences, the energy momentarily absorbed and re-radiated, will be measured by this field. FIG. 10 shows this same system of ferromagnetic strips when one of the strips, 43, has been flipped to the opposite polarity and becomes strip 44. Polarized in this manner, all of the flux, except the little bits of fringing flux at the ends, 35 and 37, flows in the gap 33 as indicated by the flux lines 34 and 36. Such a system, having essentially no external field, is, by reciprocity, closed also to external influences. As I described it previously, the system is "clamped" being unable to receive energy from outside, or reradiate energy had it somehow received any. It is essentially a closed-core system, and for it to receive and radiate energy, a conductor would have to thread the gap 33 and close on itself. FIGS. 11 and 12 show the magnetic field patterns of the systems of strips of FIGS. 6 and 5, respectively, also as previously noted. When the gap 53 is small compared with other dimensions, the strips 61 and 63 act as if they formed a single magnet and the flux lines flow accordingly, with no flux in the gap. When the gap 53 gets large, however, the field pattern becomes more like a figure-of-eight and there will be some lengthwise flux in the gap flowing between the poles of each strip but none crosswise. Similarly, when strip 63 is flipped magnetically to become strip 64, most of the flux will flow across gap 53 as indicated by the flux lines 54 and 56, but due to the pole width there will be more lines of fringing flux, 55 and 57, than in FIG. 10. And as the gap 53 is increased relatively to other dimensions, the fringing flux will increase and spread out. Magnetic configurations of FIG. 6, as described by the flux pattern of FIG. 12, is less clamped than is the configuration of FIG. 4, which is described by the field pattern of FIG. 10. Accordingly, the configuration of FIG. 12 will be more susceptable to external fields, will be able to receive more energy from external fields and hence will re-radiable a pattern of identifiable harmonics. Which of the three basic magnetic strip configurations is preferred will depend upon the problem. It would off-hand appear that the configuration of FIGS. 1 and 2 would be most applicable to tagging books in a library while the configuration of FIGS. 5 and 6 would be best suited to tagging articles of clothing. We turn now to some general considerations applicable to all strip configurations and the magnetic systems formed thereby. First, let us consider the magnetic system formed by strips of ferromagnetic material having different hysteresis loops, as 71 and 72, FIG. 13. The magnetically harder material having coercive force H 4 , is described by loop 72, and the magnetically softer material, having coercive force H 3 , is described by loop 71. If each strip is completely isolated from the other, formed in a ring to close on itself so that such represents a closed magnetic system, and we applied a pulse of MMF sufficient to drive each into magnetic saturation at B S and B s , respectively; once the pulse of MMF is removed, the magnetization in 71 will fall back to a flux value of B r on the ordinate where H is zero, and the magnetization in 72 will fall back to B R . If both strips represented perfectly open magnetic systems (an impossibility since any strip, however short, has some length), the magnetization would fall to zero flux at points H 3 and H 4 , respectively. Since this is impossible, the magnetization in 71 will fall to some point between H 3 and B r , and that in 72 to some point between H 4 and B R , and the longer the strips the higher up on the curves will the points be. If infinitely long, the flux would fall only to B r and B R , respectively, the points of retentivity. The positions H 3 , H 4 , B r , and B R , or any points therebetween, are maintained by magnetic domain orientation in the strips, called permanent magnetism. If this orientation is sufficiently strong to resist all demagnetizing forces, including thermal agitation, magnetization in the strips will remain where it landed indefinitely. With two unlike strips of ferromagnetic material, separated but in magnetic contact, the performance is a little different. An applied MMF raises both strips to saturation at B s and B S , respectively. With the MMF released, the 71 material falls back along the demagnetization part of the hysteresis loop, through B r , and would stop somewhere between B r and H 3 if 72 wasn't riding its back. The 72 material also falls back along its demagnetization curve through B R and +B 1 , and, too, would stop somewhere between B 1 and H 4 if 71 wasn't present to serve as a keeper. The result is, the 72 material having a prevailing coercive force, drives the weaker 71 material clear down into the third quadrant to -B 1 where it adjusts to a flux value equal to +B 1 in magnitude but of opposite direction of flow. This is how my deactivatable ferromagnetic marker of U.S. Pat. No. 3,747,086 operates when the marker is deactivated. When the marker is activated, the 72 material is demagnetized under well-known alternating current technics, and the 71 material freed to respond to the alternating fields of the interrogation zone. With two identical strips of ferromagnetic material, separated by a gap but otherwise in magnetic contact, the performance is quite different yet. To explain the operation of this arrangement we are obliged to refer to FIG. 14 where two identical hysteresis loops, 81 and 82 are displayed. Normally, 82 would be the lower half of 81, and 81 would be the upper half of 82. Think of the two curves as separated and applying to two separated strips of identical ferromagnetic material. With a pulse of positive MMF simultaneously applied, strip 11 is driven into saturation at +B S , and strip 12 is driven into saturation at -B S with a similar pulse of negative MMF. With the MMF's removed, strip 11 relaxes and falls back along its demagnetization curve, through P, +B R and R, etc.,; 12 relaxes and falls back along its demagnetization curve, through P',-B R , and R', etc. The demagnetization of each strip will stop at some points such as R and R' where the coercive forces, +H and -H, are equal and opposite. The operating line of this system, therefor, is along the line ROR' through the origin. If the material used in strips 11 and 12 is properly selected, and the two strips cut as identically as we can make them, they will be unable to demagnetize each other and will simply operate in offset positions as illustrated. When situated in an interrogation zone and driven by an alternating mmf, such as 83 in FIG. 14, strip 11 will be driven to P on the positive half cycles, and to R on the negative half cycles producing the wave of flux 84, 85 in 11 and surrounding area. Strip 12 will be driven to R' on the positive half cycles, and to P' on the negative half cycles. If the two strips 11 and 12 are symmetrically situated in the integration zone, as in the center of the doorway loop, FIG. 15, the positive half cycle response, 84, of strip 11, will be cancelled by the negative half-cycle response, 87, of strip 12, and the negative half cycle responses, 85, of 11, by the positive half cycle responses, 86, of 12, and the harmonic pickup will go through a null, as already described. When, however, the strips 11 and 12 are not symmetrically situated in the interrogation zone, as on either side of the doorway, an even-ordered harmonic signal will be produced, also as already described. The situation when strips 11 and 13 are aiding each other can best be described by introducing a left-handed coordinate system for strip 13. The magnetization loops will then appear in quadrants I and IV, respectively, and the de-magnetization loops in quadrants II and III. The strips will then operate along the line RS' with a mutual coercive force -H. When an alternating mmf is applied to this configuration of strips in an interrogation zone, the small flux responses 74 and 76, and the large flux responses 75 and 77, will occur on different half cycles of the interrogation zone field, and will not cancel but will predominately produce the fundamental and odd harmonics, also as previously described. FIG. 15 schematically shows a typical doorway of an interrogation zone and the apparatus associated therewith in the energizing of the door and the detection and amplification of ferromagnetic marker signals that are picked up as a result thereof. 90 is an arrow generally pointing to the interrogation unit, or doorway, which consists of some sort of frame 91 which supports a conducting loop 92 comprised of one or more full turns of wire. The number of loop turns is an insignificant quantity, as far as this invention is concerned, and can be adjusted as required to meet or match other parameters of the system, as input and output impedances. 94 is a signal generator that is capable of originating any desirable waveform, for example, those shown in FIGS 16, 17, 18 and 19. 93 is a suitable power amplifier that is capable of energizing the doorway at any required level. 95 is a signal selection apparatus which may be a tuned harmonic selector or filter, or it may be an electronic selector, or a harmonic ratio device, as required by the selected readout system. 96 is an amplifier which receives the signal processed by 95 and amplifies it to the extent necessary to operate 97 which is the final readout, or alarm sounding, unit of the interrogation apparatus 90. FIG. 16 shows the applied waveform, a sinusoidal wave form, that is generally used in practicing this invention but under special circumstances other waveforms may also be used; for example, the saw-tooth wave of FIG. 17 which is rich in all harmonics, both odd and even. Or the square wave of FIG. 18, which is rich in odd harmonics, might be used for special purposes. Again, the half-wave rectifier wave shown by the full line segments of FIG. 19, which can be rather easily produced at very high power levels, and which is rich in direct current, fundamental and even harmonics; again, the full-wave rectifier which includes both the full-line and broken line segments of FIG. 19, and which is still richer in direct current and even harmonics. The advantage of the waveforms of FIG. 19 is that a steady magnetic field is superimposed on the varying magnetic field in the interrogation zone which, through bias, would shift the operating points on the hysteresis loops of any of the markers. FIGS. 20, 21, 22 and 23 are illustrations of the apparatus that can be used in the mass production of the ferromagnetic markers of this invention, or in flipping a marker from one operating state to another at a checkout point. FIG. 20 shows a magnetic charging unit having a N-orth pole 101 in close proximity to the ferromatnetic film marker pair 11, 12, and a remote S-outh pole 103, such that when the marker pair 11, 12 is brought in the vicinity of 101 and a unidirectional pulse of current applied to coil 102, through terminals 104, the marker 11, 12 will be magnetized with the strips in opposition regardless of the state the marker pair previously occupied. The only important requirements with this apparatus are that pole 101 be reasonably long, but not as long as the total length of strips 11 and 12, that pole 103 be short and as far removed from 101 as is reasonable and practical, and that the pulse of current applied to 102 be sufficient to flip either, or both 11 and 12, over in polarity. It should be noted that it is not essential that the marker gap 13 be centered on pole 101, and this gives some latitude in the application of this apparatus. The magnetic flux lines 106 and 107 are shown flowing from 101, the N-orth pole of the charger, into the marker pair, with flux lines 108 and 109 being those which flow out of the ends of the marker pair and ultimately back to the remote S-outh pole 103. 111 points to leakage flux lines which don't pass into the ferromagnetic marker pair 11 and 12 but which flow in space between 101 and 103. 105 is the yoke of the charger which magnetically joins poles 101 and 103, and about which coil 102 is placed. FIG. 21 illustrates a form of magnetic charging apparatus adapted to setting a marker of the FIG. 1, 2 variety in the condition where the strips 11 and 13 are in series aiding configuration. Both N-orth and s-poles 112 and 111, respectively, are in proximity to the marker pair so that when a unidirectional pulse of current is put through coil 114 by means of coil terminal ends 115 and 116, the marker pair becomes magnetized in series aiding configuration regardless of the state previously occupied. 113 is the yoke of the charger around which coil 114 is wound and which joins poles 111 and 112. 117, 118 and 119 show the lines of magnetic flux which flow during a charging operation. The apparatus of FIGS. 20 and 21 is well adapted for use in a library. For example, that of FIG. 21 can be used at a check-out desk or stand, where library patrons take-out books, while the apparatus of FIG. 20 can be used by a librarian or other library employee when books are returned to the shelves. FIG. 22 shows a form of magnetic charging apparatus adapted primarily to the mass production of ferromagnetic markers of the present invention but, as has been mentioned and will be shown, it can also be used in the daily practice of the invention to cover check-out and return procedures. Referring first to FIG. 22, 122 is a form having a rectangular cross-section around which magnetic charging coils 121 and 123 are wound in opposition at the ends of form 122. 124 is a conductor loop at the center of the form where the direction of winding of the coils is reversed. 125 and 126 are arrows indicating the relative directions of current flow in the two coils 121 and 123, respectively. The length of the form 122 is preferably the same as the overall length of the markers so that when placed inside 122 with the marker ends even with the coil form ends the markers are properly positioned within the charging coils for charging in the opposing configuration prior to attachment to goods. This same arrangement, providing it is made large enough, can of course also be used in libraries when books are returned to the shelves. If the book magnetic markers are positioned in known places and positions in books, the book can then also be appropriately positioned within 122 for the charging operation. The charger of FIG. 22 is also well suited for marking magnetically protected currency when it is returned to a bank vault, armoured truck, the cash register or safe of a store. 128 refers to one terminal end of coils 121 and 123, the other terminal end being invisible at the back. FIG. 23 shows the corresponding coil and form arrangement for the mass charging of magnetic markers in the series aiding configuration. Form 132, similar to 122, has a single coil 131 wound around it so that when current is put through it a simple solenoidal magnetic field is generated. 134 indicates a stack of markers, with ends protruding, placed in the charging coil. With this type of charger, it is not required that the markers be accurately positioned in the coil. This form of charger is also well adapted to library, bank and store use. For example, books, currency, or goods being checked out can be appropriately passed through the coil by an operator, or automatically carried through the coil by a simple conveyor, and a switch triggered at appropriate intervals to put a pulse of current through coil 131. 133 refers to one coil terminal end, a second terminal end being included but not shown. In all the marker charging apparatus here illustrated, FIGS. 20 through 23, it should be noted that it is preferable to use coils having only a few turns and carrying charging currents of the order of thousands of amperes to produce the momentary magnetic fields that are required. In this way, coil inductances can be minimized and problems of current oscillations very largely avoided. Too, charging times are also reduced to minimum values. FIG. 24 shows some of the identifiable features of a piece of U.S. currency, 150, together with an arrangement of ferromagnetic marker strips. The latter, 151 and 152, are given L-shapes and placed within the paper forming the currency. 153 and 154 are the two gaps which separate the marker strips of the marker pair. As shown, the marker pair is magnetized with the two L-shaped strips in opposition, and this is the preferred condition in which currency would be kept in a bank as this is the condition that is most susceptable to the production of identifiable signals in a doorway or other form of interrogation zone. When the money is passed out by Tellers, in legitimate operations, it would preferably be put on a small conveyor and carried through reorientation apparatus, similar to that of FIGS. 21 or 23, and the magnetic pattern changed to an aiding configuration. Under this circumstance, if the gaps 153 and 154 are small, 151 and 152 will together nearly form a closed ring and the state of magnetization held near ±B R , or the points of retentivity, and the harmonic response in an interrogation zone will be typical of that configuration. The aperature of the magnetic reorientation device, used by bank Tellers, would preferably be made so small that only a few pieces of currency could be processed at a time. This would be sufficient to satisfy the normal customer but the time involved to process enough currency to satisfy a theif would be more than he could, or would, tolerate. The option remaining available to the thief in order to put himself in a position to quickly assemble large bundles of un-re-oriented currency under his control would be to carry a rather large metal box, preferably of steel, in which to put the currency and hence to shield it from the magnetic field of the interrogation zone. But such boxes are the easiest things in this world to detect in an interrogation zone and those of us who are serious inventors go to great trouble avoiding the detection of such things. Accordingly, boxes, or bags, of this type can easily be identified by the pattern of harmonics produced, or not produced; furthermore, signal limits can be set up to sound alarms when prescribed signal amplitudes have been exceeded. Again, a large bundle of currency having the the markers uniformly polarized in opposition would be capable of inducing image magnetic fields in the box and these image fields detected by the field of the interrogation zone, unless the box was excessibely thick and hard to carry or conceal. To this end, the frequency of the interrogating field should be as low as possible so as to be able to penetrate the walls of a shielding box. Alternatively, to the pattern formed by 151 and 152, ferromagnetic material could be made to coincide with the normal pattern of the currency. The emblematic pattern 155 could be used for one strip of the pair, and the amount pattern 156 could be used for the other. These two strips could be designed to have the same essential lengths, widths, thickness, and weights so that the pair would be magnetically balanced as before described. Indeed, it is entirely possible that each piece of currency could be given an identifiable magnetic design of as much complexity as the optical design--a complexity so great that illicit traffic in money could be stopped altogether. Again, L-shaped pieces of high coercivity ferromagnetic material could be made to overlay L-shaped pieces of low coercivity ferromagnetic material, with the gaps of the latter coming at diagonal corners, as shown in FIG. 24, and the gaps of the high-coercivity material coming at the other diagonals. With this arrangement, the deactivation procedure of my U.S. Pat. No. 3,747,086 could be practiced. FIG. 25 is a schematic circuit diagram of a synchronous, or coherent detector, that is used in the detection and analysis of signals picked up by loop 92 in the interrogation zone in the practice of this invention. Terminal pairs a, b; c, d; and e, f coincide with similarly identified terminal pairs of FIG. 15. Thus, the harmonics selected by 95 are applied through transformer T 1 to the rectifier ring, comprised of CR 1 , CR 2 , CR 3 , and CR 4 , as shown. The reference voltage, which is to say, the fundamental driving voltage applied to loop 92 is applied through transformer T 2 to the center-tap of the secondary of T 1 and to the midpoint of the two equal resistors R 1 and R 2 , and hence symmetrically into the rectifier ring. Accordingly, the rectifiers are switched with the period of the voltage applied to loop 92 so that any pickup by loop 92, and passed to terminals a, b, that is not synchronous with the applied voltage will be averaged out. This detector is also phase sensitive with respect to the reference voltage so that the polarity of the d-c voltage appearing across terminals e, f reverses whenever the voltage across terminals a, b changes by 180° with respect to perfect synchronism, and this fact can by itself be used to determine the status of ferromagnetic markers passing through doorway 90, without resort to whether the harmonics are predoninately even or odd, or otherwise form some pre-determined identifiable pattern. The synchronous, or coherent, detector, sometimes also called a ring detector or demodulator, is a powerful tool when applied to the circuitry of the present invention. FIG. 26 shows an arrangement of three radiation and/or pickup loops 141, 142 and 143, the planes of which are mutually orthogonal. Such an arrangement is preferred in the practice of the present invention, both for the check-out stand and the interrogation doorway. The loops would be so disposed with respect to the pathway through them, as defined by arrow 144, that the path would make an approximate 45° angle with the planes of all three loops. Accordingly, if the conductors forming the three loops are connected in series, and all three loops have the same number of turns and enclose areas of the same size, no ferromagnetic marker could ever be more than 45° off a perfect orientation with respect to at least one loop, and hence the level of response never worse than max/√2, or approximately 0.7 max. Considering that tagged goods can be moved about with the ferromagnetic markers having all posible orientations, this arrangement of check-out and interrogation zones makes it possible to do a much better engineering job than is otherwise possible, because the maximum variations are bounded. While in places such as libraries, where the tagged goods all have a common general shape and prescribed limits of sizes, as well as definitive locations for the ferromagnetic markers, the orthogonal loop system of FIG. 26 might not have too great an importance, it seems almost mandatory in places such as large department stores where merchandise of so many sizes, shapes and descriptions is sold, and where shop-lifters employ a wide variety of schemes to hide what they are stealing. Considering the many forms in which wood, aluminum alloys, and stainless steels are available today, artistic arrangements of the loops of FIG. 26 could be worked-out by architects so that an interrogating doorway would neither be ugly or obvious. Too, if the goods sold by the several departments of the store are packaged in prescribed ways, the packages could be placed on a conveyor and readily carried through a set of orthogonal re-orienting check-out loops. While manifold other arrangements of ferromagnetic markers, methods and systems of switching marker configurations, and methods and systems of detecting marker configurations, may be possible, the fundamental ones have been disclosed herein, and minor variations would not be considered to depart from the means, method and system of this invention.
An activatable, and deactivatable ferromagnetic marker useful in tagging objects to permit selective detection of tagged objects depending upon the activation state of the marker. The marker comprises a pair of ferromagnetic elements capable of generating harmonics of an exciting oscillatory interrogating field. Both elements of each pair are essentially identical, having identical dimensions, weights and ferromagnetic properties. In one activation state, the pair generates predominately the even harmonics of the oscillatory field, while in a second activation state the pair generates predominately the odd harmonics of the oscillatory interrogating field. The system includes the marker attached to, or built within, selected objects, a means for selectively switching between the two activation states, an interrogation field, and detection means. In view of the fact that in today's technology, each marker pair can be balanced to a high degree of accuracy, and the fact that the two states of activation are precise, high sensitivity and certainty of responses are both possible.
6
CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of Korean Patent Applications No. 10-2005-0115992, filed on Nov. 30, 2005 and 10-2006-0114586, filed on Nov. 20, 2006, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. BACKGROUND [0002] 1. Field [0003] The present disclosure relates to an organic light emitting device and, more particularly, to an organic light emitting device including compounds having specific photoluminescence spectrum maximum wavelengths in a hole transporting layer and an electron transporting layer. [0004] 2. Description of the Related Technology [0005] In general, an organic light emitting device includes a pair of electrodes, such as an anode electrode and a cathode electrode, and at least one organic layer interposed between the electrodes. Holes and electrons are injected from the anode and cathode electrodes to the organic layer as a voltage is applied between the electrodes. Then, excitons with an excited energy state are produced in the organic layer, and light emits while the excitons return to the ground energy state. [0006] The organic layer of the organic light emitting device may have a single layer structure or a multilayer structure. The single layer structure only includes a light emitting layer between the two electrodes. The multilayer structure includes a light emitting layer and at least one of a hole injection layer, a hole transporting layer, an electron blocking layer, a hole blocking layer, an electron injection layer, an electron transporting layer, etc. Here, the electron blocking layer refers to a layer that regulates electron mobility in order to balance with hole mobility. [0007] The multilayer structure increases quantum efficiency and decreases drive voltage by including the layers described above therein, and improves the luminous efficiency by regulating the recombination of electrons and holes. Various research efforts have been focused on materials to enhance the performance of the organic light emitting device. SUMMARY [0008] One aspect of the instant disclosure provides an organic light emitting device that improves luminous efficiency of organic light emitting diodes, particularly, blue light emitting efficiency, and does not deteriorate other properties. [0009] One embodiment provides an organic light emitting device comprising: a first electrode; a second electrode; an emissive layer interposed between the first and second electrodes; a first organic layer interposed between the first electrode and the emissive layer, the first organic layer comprising a first compound, the first compound having a photoluminescence spectrum maximum wavelength of about 400 nm to about 500 nm; and a second organic layer interposed between the second electrode and the emissive layer, the second organic layer comprising a second compound, the second compound having a photoluminescence spectrum maximum wavelength of about 400 nm to about 500 nm. [0010] The first organic layer may be a hole transporting layer and the second organic layer may be an electron transporting layer. The first compound may comprise at least one selected from the group consisting of compounds represented by Chemical Formulas 1 to 6, 10 to 22, and 25: [0011] The first compound may be in an amount of about 50 wt % to about 100 wt % with reference to the total weight of the first organic layer. The second compound may comprise at least one selected from the group consisting of compounds represented by Chemical Formulas 7 to 9, and 27. [0012] The second compound may be in an amount of about 50 wt % to about 100 wt % with reference to the total weight of the second organic layer. The first organic layer may have a thickness of about 100 Å to about 1,500 Å. The second organic layer may have a thickness of about 150 Å to about 600 Å. The first compound may comprise one or more compounds selected from the group consisting of N,N′-di(1-naphthyl)-N-N-diphenylbenzidine (NPD), bis(4-dimethylamino-2-methylphenyl-phenylmethane, 1,1-bis(4-di-p-tolylaminophenyl)cyclohexane, and 1,1-bis(4-di-p-tolylaminophenyl)-4-phenylcyclohexane. The second compound may comprise one or more compounds selected from the group consisting of oligothiophene, perfluorinated oligo-p-phenylene, and 2,5-diarylsilole. [0013] The device may further comprise a hole blocking layer interposed between the emissive layer and the second organic layer. The device may further comprise an electron blocking layer interposed between the emissive layer and the first organic layer. The emissive layer may comprise a blue light- emitting organic compound. The first compound may comprise a blue light-emitting organic compound. The second compound may comprise a blue light-emitting organic compound. [0014] Another embodiment provides an organic light emitting display device, comprising the device described above. Yet another embodiment provides an electronic device comprising the organic light emitting display device described above. [0015] Yet another embodiment provides a method of making an organic light emitting device. The method comprises: providing a first electrode; forming a first organic layer over the first electrode, the first organic layer comprising a first compound having a photoluminescence spectrum maximum wavelength of about 400 nm to about 500 nm; forming an emissive layer over the first organic layer; forming a second organic layer over the emissive layer, the second organic layer comprising a second compound having a photoluminescence spectrum maximum wavelength of about 400 nm to about 500 nm; and forming a second electrode over the second organic layer. [0016] Forming the first organic layer may comprise using thermal evaporation or spin coating. Forming the second organic layer may comprise using vacuum-deposition. [0017] An organic light emitting device in accordance with one embodiment comprises: a first electrode; a first organic layer formed on the first electrode, including a first compound having a maximum wavelength of about 400 nm to about 500 nm shown in PL spectrum; an emissive layer provided on the first organic layer; a second organic layer, established on the emissive layer, including a second compound having a maximum wavelength of about 400 nm to about 500 nm shown in PL spectrum; and a second electrode arranged on the second organic layer. [0018] An organic light emitting device in accordance with another embodiment comprises a first electrode; a first organic layer formed on the first electrode with a first compound having a maximum wavelength of about 400 nm to about 500 nm shown in PL spectrum; an emissive layer provided on the first organic layer; a second organic layer established on the emissive layer with a second compound having a maximum wavelength of about 400 nm to about 500 nm shown in PL spectrum; and a second electrode arranged on the second organic layer. [0019] The organic light emitting device in accordance with the embodiments has an advantageous effect of increasing the blue light emitting efficiency remarkably without changing other elements' properties by forming organic layers including specific compounds at both sides of the emissive layer. BRIEF DESCRIPTION OF THE DRAWINGS [0020] FIG. 1 is a schematic cross-sectional view illustrating a structure of an organic light emitting device in accordance with one embodiment. DETAILED DESCRIPTION [0021] The instant disclosure will now be described more fully hereinafter with reference to the accompanying drawings. [0022] In an organic light emitting device having the multilayer structure described above, the hole transporting layer may serve to transport holes while improving the luminous efficiency by aiding the recombination of the holes in the emissive layer. The hole transporting layer may be configured to increase blue light emitting efficiency in addition to the aforementioned functions. For instance, Korean Publication Nos. 10-2005-0077231 and 10-2003-0058458 disclosed materials for the hole transporting layer. Furthermore, the electron transporting layer may serve to transport electrons while improving the luminous efficiency by aiding the recombination of the electrons in the emissive layer. Various materials can be used for the electron transporting layer. [0023] FIG. 1 is a cross-sectional view illustrating a structure of an organic light emitting device in accordance with one embodiment. The organic light emitting device includes a first organic layer 40 , an emissive layer 30 and a second organic layer 50 between a first electrode 10 and a second electrode 20 . [0024] In one embodiment, the first electrode 10 may serve as an anode electrode while the second electrode 20 may serve as a cathode electrode. The first electrode may be formed of, for example, ITO. The second electrode may be formed of, for example, lithium, magnesium, aluminum, aluminum-lithium, calcium, magnesium-indium, magnesium-silver, and the like. [0025] The emissive layer 30 is a layer in which holes and electrons from the first electrode 10 and the second electrode 20 recombine with each other, and then, return to the ground state to emit light. The emissive layer 30 may be formed of any suitable light-emitting material. Examples of such light-emitting material include, but are not limited to, ADN (Chemical Formula 28) and MADN(Chemical Formula 29). [0026] The first organic layer 40 may include a first compound having a photoluminescence (PL) spectrum maximum wavelength of about 400 nm to about 500 nm. The term “maximum wavelength” may also be referred to as a “peak wavelength.” The first compound serves to enhance luminance efficiency of the emissive layer 30 although the first compound itself does not emit light in the organic light emitting device. The second organic layer 50 may include a second compound having a photoluminescence (PL) spectrum maximum wavelength of about 400 nm to about 500 nm. In certain embodiments, the first and second compounds themselves may be blue light emitting materials. The first and second compounds may be different from each other. [0027] In one embodiment, the first organic layer 40 may be a hole transporting layer. The hole transporting layer serves to transport holes from the anode electrode to the emissive layer efficiently. In addition to the first compound described above, the hole transporting layer may further include at least one of TPTE (Chemical Formula 23) and MTBDAB (Chemical Formula 24). It will be appreciated that any other suitable hole transporting material can be used for the first organic layer 40 . [0028] Examples of the first compound for the hole transporting layer may include, but are not limited to, N,N′-bis(3-methylphenyl)-N,N′diphenyl-[1,1-biphenyl-4,4′diamine (TPD, Chemical Formula 1), N,N′-di(naphthalene-1-yl)-N,N′diphenylbenzidine (α-NPD, Chemical Formula 2), Spiro-NPD (Chemical Formula 3), and Spiro-TAD (Chemical Formula 4). [0029] Other examples of the first compound include materials having a hole-injection property, such as copper phthalocyanine (CuPc), TCTA that is a starburst-type amine (Chemical Formula 5), m-MTDATA (Chemical Formula 6), and HI406 (available from Idemitsu Kosan Co., Ltd., Tokyo, Japan). [0030] Yet other examples of the first compound may include Flrpic (Chemical Formula 10), CzTT (Chemical Formula 11), PPCP (chemical Formula 12), DST (Chemical Formula 13), TPA (Chemical Formula 14), Spiro-DPVBi (Chemical Formula 15), AZM-Zn (Chemical Formula 16), Anthracene (Chemical Formula 17), TPB (Chemical Formula 18), OXD-4 (Chemical Formula 19), BBOT (Chemical Formula 20), compound A (Chemical Formula 21), compound B (Chemical Formula 22), and a compound represented by Chemical Formula 25. [0031] Further, N,N′-di(1-naphthyl)-N-N-diphenylbenzidine (NPD), bis(4-dimethylamino-2-methylphenyl-phenylmethane, 1,1-bis(4-di-p-tolylaminophenyl)cyclohexane, 1,1-bis(4-di-p-tolylaminophenyl)-4-phenylcyclohexane, etc., can be used solely or mixed with one or more of the examples of the first compound described above. [0032] In another embodiment, the first organic layer 40 may be formed by doping a metal phthalocyanine organic compound with a p-type semiconductor material. Moreover, in addition to the aforementioned examples of the first compound, various materials disclosed in Japanese Patent Laid-Open Nos. 2000-192028, 2000-191560, 2000-48955, 2000-7604 and 1998-11063, and U.S. Pat. No. 6,591,636 can also be used as the first compound. [0033] In one embodiment, the first compound may be in an amount of about 30 wt %-100 wt % with reference to the total weight of the first organic layer 40 . Optionally, the first compound may be in an amount of about 50 wt % to about 100 wt % with reference to the total weight of the first organic layer 40 . [0034] The thickness of the hole transporting layer may be in a range of about 100 Å to about 1,500 Å. The first compound may be included in the hole transporting material by thermal evaporation or spin coating. [0035] In one embodiment, the second organic layer 50 may be an electron transporting layer. The electron transporting layer serves to transport electrons from the cathode electrode to the emissive layer efficiently. In addition to the second compound described above, the second organic layer 50 may further include any suitable electron transporting materials. Examples of the electron transporting material include, but are not limited to, aluminum complex (Alq3-(tris(8-quinolinolato)-aluminum)), and a compound represented by Chemical Formula 26. [0036] The electron transporting material may include the second compound which has a PL spectrum maximum wavelength of about 400 nm to about 500 nm. Examples of the second compound include, but are not limited to, Bepp2 (Chemical Formula 7), Bpy-OXD (Chemical Formula 8), Bpy-OXDpy (Chemical Formula 9), the Chemical Formula 27, a compound represented by Chemical Formual 27, oligothiophene, perfluorinated oligo-p-phenylene, 2,5-diarylsilole, etc. and their derivatives. [0037] In one embodiment, the second compound may be in an amount of about 30 wt % to about 100 wt % with reference to the total weight of the second organic layer 50 . Optionally, the second compound may be in an amount of about 50 wt % to about 100 wt % with reference to the total weight of the second organic layer 50 . [0038] The second compound may be vacuum-deposited to the electron transporting material to form an electron transporting layer. Here, the thickness of the electron transporting layer may be in a range of about 150 to about 600 Å. [0039] The organic light emitting device in accordance with another embodiment includes a first organic layer 40 , an emissive layer 30 and a second organic layer 50 between a first electrode 10 and a second electrode 20 . The first organic layer 40 may be formed of a first compound having a PL spectrum maximum wavelength of about 400 nm to about 500 nm. The second organic layer 50 may be formed of a second compound having a PL spectrum maximum wavelength of about 400 nm to about 500 nm. In this embodiment, the first and second compounds in the above-mentioned wavelengths may be blue light emitting materials. The first and second compounds may be different from each other. [0040] In this embodiment, the first organic layer may be formed solely of the first compound and the second organic layer may be formed solely of the second compound. The first and second organic layers may serve as a hole transporting layer and an electron transporting layer, respectively. The first compound for the hole transporting layer may be one or more of the examples of the first compound described above. One or more of the examples of the second compound described above can be used as the second compound. [0041] In the illustrated embodiment, the organic light emitting device may also include an electron injection layer 60 , a hole blocking layer 70 , an electron blocking layer 80 , and a hole injection layer 90 . It will be appreciated that at least one of the foregoing layers 60 , 70 , 80 , and 90 can be omitted. It will also be appreciated that the organic light emitting device may further include additional layers depending on its design. [0042] In another embodiment, an organic light emitting display device may include the organic light emitting device described above. In such an embodiment, the display device may include an array of pixels, each pixel including at least one organic light emitting device described above. [0043] In yet another embodiment, an electronic device may include the display device described above. Examples of the electronic device include, but are not limited to, various consumer electronic products. The consumer electronic products may include, but are not limited to, a mobile phone, a telephone, a television, a computer monitor, a computer, a hand-held computer, a personal digital assistant (PDA), a microwave, a refrigerator, a stereo system, a cassette recorder or player, a DVD player, a CD player, a VCR, an MP3 player, a radio, a camcorder, a camera, a digital camera, a portable memory chip, a washer, a dryer, a washer/dryer, a copier, a facsimile machine, a scanner, a multi-functional peripheral device, a wrist watch, a clock, and the like. EXAMPLE 1 [0044] A hole transporting layer having a thickness of 15 nm is formed by using TPTE (Chemical Formula 23) and a compound represented by Chemical Formula 25 as a hole transporting material on the surface of a substrate, on which an ITO film is deposited as an anode electrode. After the formation of the hole transporting layer, an emissive layer having a thickness of 30 nm is established by depositing Blue dopant BD118 of Idemitsu Kosan, Co., Ltd. (Tokyo, Japan) to ADN (Chemical Formula 28) in a concentration of 1% under a gas pressure of 10 −7 torr. After depositing an emissive layer, an electron transporting layer of compound 27 is formed with a thickness of 25 nm. EXAMPLE 2 [0045] A hole transporting layer having a thickness of 15 nm is formed by using alpha-NPD of Chemical Formula 2 under a gas pressure of 10 −7 torr on the surface of a substrate, on which an ITO film is deposited as an anode electrode. After the formation of the hole transporting layer, an emissive layer having a thickness of 30 nm is established by depositing Blue dopant BD118 of Idemitsu Kosan, Co., Ltd. to ADN in a concentration of 1% under a gas pressure of 10 −7 torr. After forming an emissive layer, the electron transporting layer having a thickness of 25 nm is formed by using a compound represented by Chemical Formula 27. EXAMPLE 3 [0046] A hole transporting layer having a thickness of 15 nm is formed by using alpha-NPD of Chemical Formula 2 under a gas pressure of 10 −7 torr on the surface of a substrate, on which an ITO film is deposited as an anode electrode. After the formation of the hole transporting layer, an emissive layer having a thickness of 30 nm is established by depositing Blue dopant BD118 of Idemitsu Kosan, Co., Ltd. to ADN in a concentration of 1% under a gas pressure of 10 −7 torr. After forming an emissive layer, the electron transporting layer having a thickness of 25 nm is formed by using a compound represented by Chemical Formula 8. Comparative Example 1 [0047] A hole transporting layer having a thickness of 15 nm is formed by using a compound represented by Chemical Formula 2 under a vacuum gas pressure of 10 −7 torr on the surface of a substrate, on which an ITO film is deposited as an anode electrode. After the formation of the hole transporting layer, an emissive layer having a thickness of 30 nm is established by depositing Blue dopant BD118 of Idemitsu Kosan, Co., Ltd. to ADN in a concentration of 1% under a gas pressure of 10 −7 torr. After forming an emissive layer, the electron transporting layer having a thickness of 25 nm is formed by using Alq3. Comparative Example 2 [0048] A hole transporting layer having a thickness of 15 nm is formed by using MTBDAB (Chemical Formula 24) under a gas pressure of 10 −7 torr on the surface of a substrate, on which an ITO film is deposited as an anode electrode. After the formation of the hole transporting layer, an emissive layer having a thickness of 30 nm is established by depositing Blue dopant BD118 of Idemitsu Kosan, Co., Ltd. to ADN in a concentration of 1% under a gas pressure of 10 −7 torr. After forming an emissive layer, the electron transporting layer having a thickness of 25 nm is formed by using a compound represented by Chemical Formula 27. Experimental Example [0049] The Examples and the Comparative Examples described above were compared with one another in terms of luminance, luminous efficiency and color coordinate at 100 mA/cm 2 . TABLE 1 Luminous Luminance Efficiency (cd/a) X Y Example 1 8650 8.65 0.14 0.25 Example 2 7500 7.5 0.140 0.25 Example 3 7800 7.8 0.140 0.25 Comparative 6320 6.328 0.140 0.25 Example 1 Comparative Example 2 6725 6.7 0.140 0.25 [0050] As shown in Table 1, the color coordinate properties are not changed while the luminance and the luminous efficiencies improve remarkably when the Examples are compared with the Comparative Examples. The first and second organic layers formed at both sides of the emissive layer serve to well maintain the charge balance between holes and electrons. In the foregoing discussions, those referred to as comparative examples do not necessarily represent prior art and the term “comparative example” does not constitute an admission of prior art. [0051] In the embodiments described above, the first organic layer serves as a hole transporting layer and the second organic layer serves as an electron transporting layer. In other embodiments, other organic layers, such as hole injection layer, hole blocking layer, electron injection layer, electron blocking layer, and the like can be further included in the organic light emitting device. [0052] Although certain embodiments have been shown and described, it would be appreciated by those skilled in the art that changes might be made in those embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined in the claims and their equivalents.
The instant disclosure relates to an organic light emitting device with an improved blue light emitting efficiency. One embodiment of the organic light emitting device has an advantageous effect of increasing the blue light emitting efficiency remarkably without changing other elements' properties by forming organic layers including compounds having specific wavelengths at both sides of the emissive layer or by fabricating the organic layers with the compounds having specific wavelengths.
7
[0001] The invention relates to a method of fabricating a composite material connecting rod made of fabric woven from reinforcing fibers such as carbon fibers. BACKGROUND OF THE INVENTION [0002] Such a connecting rod, shown in FIG. 1 with the reference 1 , has a generally tubular hollow main body 2 extending along a general direction AX and extended at each of its ends by respective two-lug clevises, these clevises being given references 3 and 4 . [0003] In a method known from patent document FR 2 893 532, the connecting rod is fabricated using a piece of reinforcing fiber fabric that is cut to have a shape as shown in FIG. 2 . This shape comprises a central portion for the hollow main body 2 and four extensions, each corresponding to a respective one of the clevis lugs. [0004] The fabric used is a three-dimensional woven fabric of carbon fibers, i.e. a fabric of relatively large thickness made up of reinforcing fibers that are woven together in three dimensions. By way of example, such a three-dimensional fabric corresponds to a 2.5 D type fabric. [0005] Such a fabric has a plurality of layers of longitudinal fibers, and a plurality of layers of transverse fibers that are woven together in such a manner that the fibers extending in one direction are interlinked with the fibers in a plurality of other layers in order to constitute a non-separable fabric. [0006] The fabric may optionally be reinforced in the clevises: some of the fibers of the various layers are then no longer interlinked in the clevises so as to leave layers that are not mutually interlinked. This makes it possible to insert additional layers in the clevises in order to increase their thickness. [0007] Additional fibers extending substantially perpendicularly to the plane of the layers may subsequently be stitched through the various layers making up the clevises in order to secure them to one another. [0008] Fabricating such a clevis consists in folding the piece of fabric shown in FIG. 2 , which piece of fabric is optionally reinforced in its clevises, by applying it onto a mandrel or the like and then bringing together its two opposite edges. The edges can then be connected together, e.g. by stitching, prior to injecting resin into the reinforcing fiber fabric and heating the assembly in order to polymerize the resin. [0009] The nominal thickness of the wall forming the connecting rod is limited by the thickness of the three-dimensional fabric that is used for making it, given that deciding to use a thick fabric increases the cost of such a fabric very considerably, in particular because it involves reducing the speed of weaving very considerably. [0010] In practice, given current sales costs, it is not possible to envisage using a fabric having a thickness of more than two or three centimeters. It can be understood that such a limitation on thickness puts a limitation on the forces that can be accepted by the connecting rod in question as a whole, and also by its clevises. OBJECT OF THE INVENTION [0011] The object of the invention is to provide a solution for remedying the above drawbacks. SUMMARY OF THE INVENTION [0012] To this end, the invention provides a method of fabricating a connecting rod out of composite material from three-dimensional fabric of woven reinforcing fibers, the connecting rod extending in a main direction, and the method comprising the operations of: cutting out one or more base pieces from one or more three-dimensional fabrics; cutting out one or more reinforcing pieces from one or more three-dimensional fabrics; installing the various pieces on a support in order to shape them in a configuration in which the base pieces and the reinforcing pieces are superposed; securing the various pieces to one another by stitching with reinforcing fibers in order to constitute a reinforcing fiber preform; installing the preform on a mandrel; and injecting resin into the preform and polymerizing the resin. [0019] Using this technique, a preform is made presenting thickness that is significantly greater than the thickness of the reinforcing fiber fabric that is used. [0020] The invention also provides a method as defined above, wherein the various pieces are secured to one another by means of at least one operation of stitching together a pair of edges extending along the main direction, the edges belonging to two distinct base pieces in order to secure those two base pieces to each other. [0021] The invention also provides a method as defined above, wherein the various pieces are secured to one another by means of at least one operation of stitching a reinforcing piece against a base piece in order to secure them to each other. [0022] The invention also provides a method as defined above, wherein two base pieces and two reinforcing pieces are used to make up the preform, and wherein the various pieces are secured to one another by at least one operation of stitching together two pairs of superposed edges extending in the main direction, the edges of one of the pairs belonging to two different base pieces, and the edges of the other pair belonging to two distinct reinforcing pieces, and wherein these two pairs of superposed edges are stitched together jointly. [0023] The invention also provides a method as defined above, wherein the edges that are assembled together by stitching are of complementary chamfered shapes in the region where they are stitched together. [0024] The invention also provides a method as defined above, wherein a single stitching operation is performed to secure two edges of two base pieces to each other and to a reinforcing piece. [0025] The invention also provides a method as defined above, wherein a single stitching operation is used to secure two edges of two reinforcing pieces to each other and to a base piece. BRIEF DESCRIPTION OF THE FIGURES [0026] FIG. 1 , described above, is an overall view of a known connecting rod; [0027] FIG. 2 , described above, shows the piece of fabric used for fabricating the FIG. 1 connecting rod; [0028] FIG. 3 is an overall perspective view of the connecting rod of the invention; [0029] FIG. 4 is a view showing how a three-dimensional fabric is cut out to constitute the base pieces for making the connecting rod of the invention; [0030] FIG. 5 is a cross-section view of the body of the connecting rod of the invention; [0031] FIG. 6 is a cross-section view of the body of the connecting rod in a second embodiment of the invention; [0032] FIG. 7 is a cross-section view of the body of the connecting rod in a third embodiment of the invention; and [0033] FIG. 8 is a cross-section view of the body of the connecting rod in a fourth embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION [0034] The invention is based on the idea of making a connecting rod having its wall made up of a plurality of superposed layers of three-dimensional woven fabric so as to achieve considerable thickness without it being necessary to have recourse to thick three-dimensional fabric. In practice, this solution makes it possible to make a connecting rod having a wall of thickness that may be as much as eight to ten centimeters while nevertheless having a cost of fabrication that is particularly competitive. [0035] The connecting rod of the invention is shown in [0036] FIG. 3 where it is given overall reference 6 , and it is made up of four pieces of three-dimensional fabric, comprising two base pieces 7 and 8 , and two reinforcing pieces given references 9 and 10 . [0037] The two base pieces 7 and 8 are of shapes that are generally symmetrical relative to each other about a plane P containing the longitudinal axis AX of the connecting rod, with only their chamfered edges being inverted so as to be complementary. In analogous manner, the two reinforcing pieces 9 and 10 are likewise of shapes that are generally symmetrical relative to each other about the plane P. [0038] As can be seen in FIG. 3 , the connecting rod comprises a generally tubular central body 12 that is extended at each of its ends by respective two-lug clevises. These clevises are given references 13 and 14 and each of them has two lugs given respective references 13 a, 13 b, 14 a, and 14 b. [0039] Each base piece 7 , 8 is made from a piece of three-dimensional fabric having a plane shape defined by an appropriate outline, as shown in FIG. 4 . The piece 7 has two generally rectilinear opposite edges referenced 7 a and 7 b, and the piece 8 has two generally rectilinear opposite edges referenced 8 a and 8 b. Each reinforcing piece 9 , 10 is fabricated from a plane piece of three-dimensional fabric defined by an outline that is generally rectangular or oblong. [0040] Once the pieces of fabric 7 , 8 , 9 , and 10 have been obtained, they are initially assembled to one another. Specifically, the rectangular reinforcing piece 9 is applied against and positioned on the base piece 7 in such a manner as to cover its central portion extending from the region corresponding to the lug 7 a as far as the region corresponding to the lug 7 b. [0041] The assembly formed in this way is then held in position and stitched together by means of a dedicated machine using reinforcing fibers passing through both thicknesses of three-dimensional fabric, so as to secure the reinforcing piece 9 to the base piece 7 . [0042] The procedure is analogous for positioning the reinforcing piece 10 on the base piece 8 prior to securing them to each other, likewise by stitching with reinforcing fibers passing through both thicknesses of three-dimensional fabric. [0043] Once these two elements have themselves been assembled, they are put into place on a support so as to give them the rounded shapes that correspond to the connecting rod. [0044] Once both assemblies are in place, the edges 7 a and 8 a of the base pieces 7 and 8 are positioned so as to be touching, and in analogous manner the edges 7 b and 8 b are likewise touching, while nevertheless conforming to an arrangement corresponding to that of the connecting rod as shown in FIG. 3 . [0045] At this stage, each pair of touching edges is stitched together, with this being done by stitching reinforcing fibers firstly to secure the edges 7 a and 8 a together, and secondly to secure the edges 7 b and 8 b together. [0046] In general, each of the preform assemblies may be positioned relative to the other on a mandrel, prior to proceeding with a single stitching operation serving to assemble together the various pieces. [0047] At this stage, a preform has been made that is constituted by the base pieces 7 and 8 and by the reinforcing pieces 9 and 10 that are secured to one another. The reinforcing pieces are situated on the inside of the wall forming the connecting rod, each extending from one clevis lug to the other clevis lug at the opposite end along the axis AX. [0048] As can be seen in the cross-section of FIG. 5 , the reinforcing piece 9 is fastened to the base piece 7 by a set of crossing fibers referenced 12 . In analogous manner, the reinforcing piece 10 is fastened to the base piece 8 by another set of reinforcing fibers 13 . [0049] The edges 7 a and 8 a are secured to each other by a set of crossing fibers 14 , and the edges 7 b and 8 b are secured to each other by another set of reinforcing fibers, referenced 15 . [0050] Various stitching solutions may be adopted for securing the edges to each other. In the example of FIG. 5 , the edges are of chamfered shape, such that they overlie each other in part when they are in position. Under such conditions, the stitching is formed by fibers extending in a direction that is radial relative to the axis AX of the connecting rod, each stitched fiber crossing through a thickness of chamfered three-dimensional fabric corresponding to the piece 7 and through a thickness of chamfered three-dimensional fabric corresponding to the piece 8 . [0051] Once the preform has been made up, it is installed on a new mandrel, different from the mandrel used for the stitching operation, and of a shape corresponding to the inside shape of the connecting rod. The assembly is then placed in an appropriate injection mold. At this stage, the resin is injected into the entire preform, and the resin is then polymerized, e.g. by heating for a predetermined duration. [0052] Once the unfinished part has been made in this way, various machining operations are performed, in particular to give the lugs of the clevises their final shapes, and to pierce these clevis lugs, prior to installing bearing-forming metal rings therein. [0053] As can be in particular in FIG. 3 , the connecting rod as formed in this way presents significant thickness in its flanks, such that this large thickness serves to provide considerable reinforcement not only to the connecting rod as a whole, but also to the lugs of its clevises, thereby contributing to reducing stresses in the force-insertion zones as constituted by the clevises. [0054] Techniques other than those shown in FIGS. 3 to 5 may advantageously be envisaged for assembling the various pieces of three-dimensional fabric together by stitching in order to make up the preform. [0055] To this end, the example of FIG. 6 shows another connecting rod in accordance with the invention, having two base pieces 7 ′ and 8 ′ and two reinforcing pieces 9 ′ and 10 ′. The fabrication of this connecting rod does not include, properly speaking, a step of securing each reinforcing piece to a corresponding base piece. [0056] In the example of FIG. 6 , the opposite edges of the base pieces are arranged to be secured to each other by stitching, as in the example of FIGS. 3 to 5 , however in this example, the reinforcing pieces 9 ′ and 10 ′ present chamfered opposite edges that are for securing to each other by stitching. [0057] Once the various pieces have been put into place so that relative to one another they are in the arrangement they are to present in the finished connecting rod, one of the pairs of edges of the base pieces 7 ′ and 8 ′ for securing together by stitching extends radially over one of the pairs of edges of the reinforcing pieces 9 ′ and 10 ′ that are to be secured to each other by stitching, running therealong, as can be seen in the top portion of FIG. 6 . [0058] In analogous manner, the other pair of edges of the base pieces 7 ′ and 8 ′ for securing to each other extends radially over the other pair of edges of the reinforcing pieces 9 ′ and 10 ′ that are to be secured to each other, as can be seen in the bottom portion of FIG. 6 . [0059] A single operation is then performed of stitching together all four edges in the top portion of the preform as seen in section, and another single operation is performed of stitching together all four edges in the bottom portion of the preform as seen in section, thereby serving to secure to one another the various pieces making up the preforms while also simultaneously securing the various edges to one another. [0060] In analogous manner, it is also possible to offset the reinforcing pieces angularly around the longitudinal axis of the connecting rod, as shown diagrammatically in FIG. 7 . [0061] In FIG. 7 , the connecting rod is likewise made up of two base pieces 7 ″ and 8 ″, and of two reinforcing pieces 9 ″ and 10 ″, however these various components are assembled by means of four sets of stitching, each serving to secure together two edges and to secure those two edges to a third element. [0062] As can be seen in FIG. 7 , this assembly comprises stitching 12 ″ situated in the left portion of the section of the connecting rod and crossing through the base piece 7 ″ together with two contiguous edges of the reinforcing pieces 9 ″ and 10 ″. In analogous manner, other stitching 13 ″ situated in the right portion of FIG. 7 crosses through the base piece 8 ″ and through two other contiguous edges of the reinforcing pieces 9 ″ and 10 ″. [0063] Furthermore, stitching 14 ″ situated in the top portion of the cross-section crosses through two contiguous edges of the base pieces 7 ″ and 8 ″ and also through the reinforcing piece 10 ″. Other stitching 15 ″ situated in the bottom portion of the cross-section crosses through two other contiguous edges of the base pieces 7 ″ and 8 ″, and also through the reinforcing piece 9 ″. [0064] It can readily be understood that, in this example, assembling together the various components consists in beginning by performing the stitching 12 ″ and 13 ″ prior to performing the stitching 14 ″ and 15 ″ in order to make up a preform ready for receiving a mandrel for installing in an injection mold where resin is injected and then polymerized. [0065] In the example of FIGS. 3 to 5 , the reinforcing pieces are arranged in such a manner as to enable them to reinforce the lugs of the clevises of the connecting rod by increasing their thickness. [0066] It should be observed that the thickness of the clevis lugs may be further increased by inserting additional layers of fabric therein. In other words, the invention does not in any way exclude the possibility of having non-interlinked fabric layers of the three-dimensional fabric in each clevis in order to be able to insert layers of two-dimensional woven fabric therein prior to securing them all together by stitching using transverse reinforcing fibers. [0067] As mentioned above, and as can be seen in the examples of the various figures, the edges that are stitched together are advantageously of complementary chamfered shapes, so that when they are in position one against the other, together they form a portion of fabric that presents thickness that is substantially constant and that corresponds to the nominal thickness of the three-dimensional fabric in which they are made. [0068] Furthermore, this chamfered shape for the assembled-together edges facilitates the stitching operation, since it then consists merely in making stitches through the chamfered portions which are superposed one on the other. [0069] In yet another embodiment, the pieces of fabric 7 , 8 , 9 , and 10 , or 7 ′, 8 ′, 9 ′, and 10 ′, or 7 ″, 8 ″, 9 ″, and 10 ″ are cut out from different three-dimensional fabrics. This makes it possible to use materials having the best-suited characteristics. [0070] By way of example, mention can be made of the pieces 7 and 8 being made of a fabric having particular properties for withstanding impacts, while the pieces 9 and 10 are taken from a fabric having superior properties in compression. [0071] In the examples shown in the figures, the stitching is performed in such a manner that the stitched fibers extend radially relative to the general direction of the connecting rod. In other words, each stitched fiber extends in a direction that is normal to the outside face of the connecting rod in the region where the fiber is stitched. [0072] Advantageously, the fibers may also be stitched in one or two directions that are oblique relative to the radial direction, so as to oppose shear stresses that may appear between the layers of the connecting rod when it is itself stressed. Under such circumstances, the stitched fibers are then inclined relative to the normal to the outside face in the region of the stitching. [0073] The implementation of such a technique for arranging the pieces of FIG. 5 is shown in FIG. 8 . In this example, the connecting rod 6 ″′ has a reinforcing piece 9 ″′ fastened to a base piece 7 ″′, and in analogous manner a reinforcing piece 10 ″′ fastened to the other base piece 8 ″′. [0074] As can be seen clearly in FIG. 8 , these various elements are fastened to one another by fibers 12 ″′, 13 ″′, 14 ″′, and 15 ″′ that are stitched in different oblique directions so as to be effective in opposing relative slip between the various layers, in particular when the connecting rod is stressed in twisting.
A method of fabricating a connecting rod ( 6 ) out of composite material using three-dimensional fabric of woven reinforcing fibers, the connecting rod ( 6 ) extending in a main direction. The method comprises the steps of: cutting out one or more base pieces ( 7, 8 ) from a three-dimensional fabric; cutting out one or more reinforcing pieces ( 9, 10 ) from a three-dimensional fabric; installing the various pieces ( 7, 8, 9, 10 ) on a support in order to shape them; securing the various pieces ( 7, 8, 9, 10 ) to one another by stitching ( 12, 13, 14, 15 ) using reinforcing fibers in order to constitute a reinforcing fiber preform; installing the preform on a mandrel; and injecting resin into the preform and polymerizing the resin.
5
FIELD OF THE INVENTION The present invention relates to a silver halide photographic material which permits formation of direct positive images using a highly stable processing solution and to an image formation method using this material. More particularly, the present invention relates to a silver halide photographic material that is useful for computer output film (COM film) and to an image formation method using this material. BACKGROUND OF THE INVENTION The rapid development of computers has established the information industry of today and has been accompanied by very active research into methods for outputting massive amounts of records. Silver halide photographic materials that are suitable for reversal processing are used as recording materials in this field. Processing in this reversal development consists of forming a negative image by a first development process, and not subjecting it to fixing but to bleaching to desilver the reduced silver in the negative image. The remaining undeveloped image silver halide is exposed and a second development is performed to produce a positive image. Because of the complexity of the processing stages, the film finishing rate is slow and there are fluctuations in the maximum density (Dmax) and minimum density (Dmin). In addition, there are problems of environmental pollution since powerful oxidizing agents such as potassium dichromate have to be used in the bleaching solution. Photographic methods for producing direct positive images without a reversal processing stage or a negative film are well-known methods for resolving these problems. From the point of view of practical use, with the exception of special methods, these conventional methods for producing positive images using direct positive silver halide photographic materials can be classified into two types. One type uses a prefogged silver halide emulsion and a direct positive image is obtained after development by using solarization or the Herschel effect, to break down the fogging nuclei (the latent image) of exposed portions. The other type uses a non-fogged internal latent image type silver halide emulsion and direct positive images are obtained by performing surface development while effecting fogging treatment or after effecting a fogging treatment, following image exposure. This "internal latent image type silver halide emulsion" is a silver halide emulsion in which the silver halide grains have photosensitive nuclei mainly in their interiors and exposure results in formation of a latent image mainly inside the grains. The second procedure gives greater speeds than the first type and is more suited to applications where high speeds are demanded, and the present invention relates to the internal latent image type silver halide emulsion. A variety of techniques are known in this technical field, principal examples being disclosed in U.S. Pat. Nos. 2,592,250, 2,466,957, 2,497,875, 2,588,982, 3,317,322, 2,497,875, 3,761,266, 3,761,276 and 3,796,577 and British Patents 1,151,363, 1,150,553 and 1,011,062. These known methods make it possible to produce a photosensitive material with comparatively high speed as a direct positive type material. Details of the mechanism of direct positive image formation are given in, e.g., The Theory of the Photographic Process by T. H. James, (4th edition), Chapter 7, pages 182-193 and U.S. Pat. No. 3,761,276. It is believed that as the result of a surface desensitization action originating in an internal latent image produced inside the silver halide in response to initial image exposure, there occurs selective formation of fogging nuclei only on the surfaces of the silver halide grains in unexposed portions, and that following this by ordinary surface development processing results in formation of a photographic image (direct positive image) in the unexposed portions. Methods which are generally called "light fogging methods" in which the entirety of photosensitive surfaces are subjected to a second exposure (e.g., British Patent 1,151,363) and methods called "chemical fogging methods" using nucleating agents are known as means for selectively producing fogging nuclei as noted above. A description of the chemical fogging method is given, e.g., at pages 72-87 of Research Disclosure Volume 151, No. 15162 (published November 1976). Materials with which nucleating agent effects are achieved only at a high pH of 12 or more are used in conventional chemical fogging methods, but deterioration of the developing agent due to air oxidation is liable to occur in these high pH conditions and consequently there is the drawback that the development activity is extremely reduced. There is also the drawback that processing takes a long time because the development rate is slow, and in particular the processing takes even longer if a low pH developing solution is used. There is also the drawback that processing takes a long time even if the pH is increased to 12 or more. In contrast, light fogging methods are comparatively advantageous for practical uses since they do not need high pH conditions. On the other hand, there are various technical problems if a variety of technical purposes are to be served over a broad photographic field. That is, since a light fogging method is based on formation of fogging nuclei through photolysis of silver halide, the appropriate illuminance and quantity of exposure vary depending on the type and characteristics of the silver halide used. This means that there are the drawbacks that it is difficult to achieve constant performance and that the development apparatus is complex and costly. There is the further drawback that development takes a long time. It has been found difficult to produce good, stable direct positive images in both these conventional types of fogging methods. Compounds which display a nucleating action even at a pH of 12 or less have been proposed in JP-A-52-69613 (the term "JP-A" used herein means an "unexamined published Japanese patent application") and U.S. Pat. Nos. 3,615,615 and 3,850,638 as means for resolving this problem but these nucleating agents have the drawbacks that they act on silver halide during storage of sensitive material prior to processing and that they themselves are decomposed, leading to a fall in the post-processing maximum image density. It has been disclosed in U.S. Pat. No. 3,227,552 that intermediate density development rates are increased by use of hydroquinone derivatives. However, even when these derivatives are used the development rate is still insufficient and with a developing solution with a pH of 12 or less only an unsatisfactory development rate is obtained. JP-A-60-170843 discloses addition of mercapto compounds containing carboxylic acid groups or sulfonic acid groups to increase the maximum image density, but the effects of adding these compounds are slight. JP-A-55-134848 discloses that processing in a processing solution (pH 12.0) containing tetraazaindene compounds in the presence of a nucleating agent reduces the minimum image density and prevents formation of a re-reversal negative image, but it is not possible to achieve a high maximum image density or quick development rates with this method. JP-B-45-12709 (the term "JP-B" as used herein means an "examined Japanese patent publication") discloses addition of triazolinethione compounds and tetrazolinethione compounds as antifoggants to sensitive materials for forming direct positive images by a light fogging process, but it is not possible to achieve high maximum image density or a rapid development rate with this method. Thus, conventional techniques do not permit direct positive images with high maximum image density and low minimum image density to be produced in a short time. There is also the problem that, in general, the higher the speed of a direct positive emulsion, the greater is the occurrence of re-reversal negative images in high illuminance exposure. For COM film in particular, high speed with short CRT exposure is demanded, and so it is important to prevent re-reversal negative images on high illuminance exposure. Japanese Patent Applications 61-136949 and 61-153481 disclose techniques for resolving the above noted problems but these procedures are unsatisfactory in respect of prevention of re-reversal negative images. SUMMARY OF THE INVENTION A first object of the present invention is to provide a method for rapid and stable formation of direct positive images with a high Dmax and a low Dmin through development processing of non-prefogged internal latent image type silver halide photographic materials in the presence of a nucleating agent. A second object of the present invention is to provide direct positive silver halide photographic material for COM film which makes use of the reversal characteristics of internal latent image type silver halide emulsions and nucleating agents. A third object of the present invention is to provide direct positive silver halide photographic material with which there is little occurrence of rereversal negative images in high illuminance exposure. A fourth object of the present invention is to provide a method of forming direct positive images with which there is little variation of Dmax or Dmin even if the pH of developing solution is varied. A fifth object of the present invention is to provide direct positive silver halide photographic material with which there is little variation of Dmax or Dmin even during long-term storage of the photosensitive material. It has now been found that these and other objects of the present invention are achieved by a method for forming a direct positive image comprising the steps of: (a) imagewise exposing a photosensitive material comprising a support having thereon at least one light-sensitive silver halide emulsion layer containing non-prefogged silver halide grains capable of forming an internal latent image; at least one of the light-sensitive emulsion layer or the other hydrophilic colloidal layer in the photosensitive material containing the following compound (a): ##STR2## (b) developing said exposed material in the presence of a developing agent and at least one nucleating agent; and (c) at least one of fixing and bleaching said developed photosensitive material to form a positive image. DETAILED DESCRIPTION OF THE INVENTION The amount of compound (a) added per 1 mole of the silver halide is preferably 1×10 -6 to 1×10 -2 and more preferably 1×10 -5 to 1×10 -2 moles. Compound (a) of the present invention is described as a nucleation accelerator in Japanese Patent Applications 61-136948, 61-136949, 63-51288, 63-51287 and 63-82543, JP-A-63-8740, and JP-A-63-231448. As used herein, the term "nucleating agent" means a substance which acts to form a direct positive image and becomes effective at the time of surface development processing of a non-prefogged internal latent image type silver halide emulsion. All known compounds used for the purpose of nucleating internal latent image type silver halides may be used as nucleating agents in the present invention. Two or more types of nucleating agents may be used in combination. In more detail, these include, e.g., the nucleating agents described in Research Disclosure No. 22,534 (published January 1983, pages 50 to 54), and they can be broadly classified into three groups, of hydrazine compounds, quaternary heterocyclic compounds and compounds other than these. The heterocyclic compounds include, for example, the compounds described in Research Disclosure No. 15,162 (published November 1976, pages 76 to 77) and Research Disclosure No. 23,510 (published November 1983, pages 346 to 352). More specifically, they include the substances described in the patents noted below. Examples of hydrazine nucleating agents having silver halide adsorption groups include those disclosed in U.S. Pat. Nos. 4,030,925, 4,080,207, 4,031,127, 3,718,470, 4,269,929, 4,276,364, 4,278,748, 4,385,108 and 4,459,347, British Patent 2,011,391B, JP-A-54-74729, JP-A-55-163533, JP-A-55-74536 and JP-A-60-179734. Other examples of hydrazine nucleating agents include the compounds disclosed in JP-A-57-86829 and U.S. Pat. Nos. 4,560,638, 4,478, 2,563,785 and 2,588,982. Examples of quaternary heterocyclic compounds include the compounds disclosed in Research Disclosure No. 22,534, JP-B-49-38164, JP-B-52-19452 and JP-B-52-47326, JP-A-52-69613, JP-A-52-3426, JP-A-55-138742, JP-A-60-11837, U.S. Pat. No. 4,306,016 and Research Disclosure No. 23,213 (published August 1983, pages 267 to 270). Preferred nucleating agents in the present invention are represented by formulae (N-I) and (N-II): ##STR3## In the formula, Z 1 represents a nonmetallic atomic group necessary for forming a 5- to 6-membered hetero ring. This hetero ring may further be fused with an aromatic ring or hetero ring. R 1 represents an aliphatic group and X represents ##STR4## Q represents a nonmetallic atomic group necessary for forming a 4- to 12-membered non-aromatic hydrocarbon ring or non-aromatic hetero ring. At least one of R 1 , Z 1 and Q contain alkynyl group, and at least one of R 1 , Z 1 and Q may contain a group for accelerating adsorption to silver halide. Y represents a counter ion necessary for charge balance, and n is the number of counter ions needed to establish the charge balance. The nucleating agents represents by formula (N-I) are now described in more detail. The hetero-rings that are completed by Z 1 include, e.g., quinolinium, benzimidazolium, pyridinium, thiazolium, selenazolium, imidazolium, tetrazolium, indolenium, pyrrolinium, phenanthridinium, isoquinolinium and naphthopyridium nuclei. Z 1 may be substituted by a substituent, including alkyl, alkenyl, aralkyl aryl, alkynyl, hydroxyl alkoxy and aryloxy groups, halogen atoms and amino, alkylthio, arylthio, acyloxy, acylamino, sulfonyl, sulfonyloxy, sulfonylamino, carboxyl, acyl, carboamoyl, sulfamoyl, sulfo, cyano, ureido, urethane, carbonate, hydrazine, hydrazone and imino groups. At least one of these substituents may be selected as substituents for Z 1 and if there are two or more they may be the same or different. Also, these substituents may be further substituted by these substituents. It is also possible to have as substituents for Z 1 a heterocyclic quaternary ammonium group that is completed by Z 1 via divalent linking group L 1 . This structure is dimer structure. Preferred heterocyclic group nuclei formed by Z 1 are quinolinium, benzimidazolium, pyridinium, acridinium, phenanthridinium, naphthopyridinium and isoquinolinium nuclei. More preferably they are quinolinium, naphthopyridinium or benzimidazolium nuclei and most preferably they are quinolinium nuclei. The aliphatic groups for R 1 are preferably unsubstituted alkyl groups having 1 to 18 carebon atoms or substituted alkyl groups with alkyl portions having 1 to 18 carbon atoms. The substituents for R 1 include those described for Z 1 . R 1 is preferably an alkynyl group, and a propargyl group is most preferred. Q is an atomic group necessary for forming a 4 to 12 membered non-aromatic hydrocarbon ring or non-aromatic hetero ring. Such rings may further be substituted by the substituents described for Z 1 . Examples of non-aromatic hydrocarbon rings when X is a carbon atom include cyclopentane, cyclohexane, cyclohexene, cycloheptane, indan and tetralin. The non-aromatic hetero-rings are rings containing, e.g., nitrogen, oxygen, sulfur or selenium atoms as hetero-atoms and examples when X is a carbon atom include tetrahydrofuran, tetrahydropyran, butyrolactone, pyrrolidone and tetrahydrothiophene rings. Examples when X is a nitrogen atom include pyrrolidine, piperidine, pyridine, piperazine, perhydrothiazine, tetrahydroquinoline and indoline rings. Cases in which X is a carbon atom, are preferred for the ring nuclei that are formed by Q, and examples of the ring nuclei include cyclopentane, cyclohexane, cycloheptane, cyclohexene, indan, tetrahydropyran and tetrahydrothiophene in particular. At least one of R 1 , Z 1 and Q contains an alkynyl group (preferably having 2 to 18 carbon atoms), e.g., ethynyl, propargyl, 2-butynyl, 1-methyl-propargyl, 1,1-di-methylpropargyl, 3-butynyl or 4-pentynyl groups. These may further be substituted by the groups described as substituents for Z 1 . Propargyl is the preferred alkynyl group, and in particular the case where R 1 is a propargyl group is the most preferred. Groups represented by X 1 (L 1 -- m are preferred as silver halide adsorption acceleration groups that are contained in R 1 , Q and Z 1 . X 1 here is a silver halide adsorption accelerating group; and L 1 is a divalent linking group. m is 0 or 1. Preferred examples of silver halide adsorption accelerating groups represented by X 1 include thioamido, mercapto and 5- to 6-membered nitrogen-containing heterocyclic groups. These may by substituted by the substituents described for Z 1 . Acyclic thioamido groups (e.g., thiourethane, thioureido) are preferred as thioamido groups. Heterocyclic mercapto groups (e.g., 5-mercaptotetrazole, 3-mercapto-1,2,4-triazole, 2-mercapto-1,3,4-thiadiazole, 2-mercapto-1,3,4-oxadiazole) are particularly preferred as mercapto groups for X 1 . 5- to 6-membered nitrogen-containing hetero-rings represented by X 1 contain combinations of nitrogen, oxygen, sulfur and carbon, and preferred rings include rings which form imino silver, e.g., benzotriazole or aminothiazole. Divalent linking groups represented by L 1 are atoms or atomic groups containing at least one of the elements C, N, S and O. Specifically, examples of the divalent groups include alkylene, alkenylene, alkynylene or arylene groups, --O--, --S--, --NH--, --N═, --CO-- and --SO 2 -- (which groups may be substituted) alone or in combination. Preferred examples of combinations include ##STR5## Examples of counter ions Y for charge balance include bromide, chloride, fluoride, p-toluenesulfate, ethylsulfonate, perchlorate, trifluoromethanesulfonate, thiocyanate, BF 4 - and PF 6 - ions. Preferred compounds represented by formula (N-I) contain silver halide adsorption accelerating groups, and in particular, thioamido, azole or heterocyclic mercapto groups that are used as adsorption accelerating groups X 1 are more preferred. Examples of such compounds and methods for synthesizing them are disclosed in, e.g., JP-A-63-301942 and the patents and documents cited therein. Specific examples of compounds represented by formula (N-I) are as follows, but the invention is not to be construed as being limited hereto. ##STR6## The compounds represented by formula (N-I) may be synthesized by the methods described in, e.g., Research Disclosure No. 22,534 (published January 1983, pages 50 to 54) and U.S. Pat. No. 4,471,044 or methods similar thereto. Nucleating agents represented by formula (N-II) are now described in greater detail. ##STR7## wherein R 21 represents an aliphatic, aromatic or heterocyclic group; R 22 represents hydrogen or an alkyl (preferably having 1 to 30 carbon atoms), aralkyl (preferably having 7 to 30 carbon atoms), aryl (preferably having 6 to 30 carbon atoms), alkoxy (preferably having 1 to 30 carbon atoms), aryloxy (preferably having 6 to 30 carbon atoms) or amino group; G represents a carbonyl, sulfonyl, sulfoxy, phosphoryl or iminomethylene ##STR8## group and R 23 and R 24 both represent hydrogen or one of them represents hydrogen and the other represents an alkylsulfonyl (preferably having 1 to 20 carbon atoms), arylsulfonyl (preferably having 6 to 20 carbon atoms) or acyl group. There may be formed a hydrazone structure ##STR9## in a form containing G, R 23 , R 24 and hydrazine nitrogen. The above groups may also be substituted by substituents in cases where substitution is possible. Aliphatic groups represented by R 21 in formula (N-II) are straight-chain, branched or cyclic alkyl (preferably having 1 to 30 carbon atoms), alkenyl (preferably having 2 to 30 carbon atoms) or alkynyl (preferably having 2 to 30 carbon atoms) groups. Aromatic groups represented by R 21 are single or two ring aryl groups (preferably having 6 to 30 carbon atoms), e.g., phenyl or naphthyl groups. The hetero-rings represented by R 21 are 3- to 10-membered saturated or unsaturated hetero-rings containing at least one of N, O and S, and may be single rings or may form fused rings with other aromatic rings or hetero-rings. Preferred hetero-rings are 5- to 6-membered aromatic hetero-rings and examples include pyridyl, quinolinyl, imidazolyl and benzimidazolyl groups. R 21 may be substituted by substituents. Examples of substituents include the following, and these groups may be further substituted. For example, the substituents include alkyl, aralkyl, alkoxyalkyl- or alkoxyaryl-substituted amino, acylamino, sulfonylamino, ureido, urethane, aryloxy, sulfamoyl, carbamoyl, aryl, alkylthio, arylthio, sulfonyl, sulfinyl and hydroxyl groups, halogen atoms and cyano, sulfo and carboxyl groups. These groups may be linked to form rings in cases where this is possible. Preferred groups for R 21 are aromatic, aromatic heterocyclic and aryl-substituted methyl groups, and aryl groups are more preferred. Among the groups represented by R 22 , preferred groups when G is a carbonyl group are hydrogen, alkyl groups (e.g., methyl, trifluoromethyl, 3-hydroxypropyl, 3-methanesulfonamidopropyl), aralkyl groups (e.g., o-hydroxybenzyl), aryl groups (e.g., phenyl, 3,5-dichlorophenyl, o-methanesulfonamidophenyl, 4-methanesulfonylphenyl). Preferred groups represented by R 22 when G is a sulfonyl group include alkyl groups (e.g., methyl), aralkyl groups (e.g., o-hydroxyphenylmethyl), aryl groups (e.g., phenyl) and substituted amino groups (e.g., dimethylamino). The substituents for R 22 include the substituents listed for R 21 and in addition to these, e.g., acyl, acyloxy, alkyloxycarbonyl, aryloxycarbonyl, alkenyl, alkynyl or nitro groups. These substituents may be further substituted by these substituents and they may be linked to form rings. It is preferred that R 21 or R 22 , and particularly R 21 , contain an antidiffusion groups or ballast groups for couplers. Such ballast groups have 8 or more carbon atoms and contain one or a combination of two or more groups such as alkyl, phenyl, ether, amido, ureido, urethane, sulfonamido and thioether groups. R 21 or R 22 may contain the group X 2 (L 2 -- m2 , which accelerates adsorption of the compound represented by formula (N-II) on the surfaces of silver halide grains. X 2 here has the same meaning as X 1 in formula (N-I) and is preferably a thioamido group (excluding thiosemicarbazides or a substituted thiosemicarbazide), mercapto group or 5- to 6-membered nitrogen-containing heterocyclic group. L 2 represents a divalent linking group and has the same meaning as L 1 in formula (N-I); and m2 is 0 or 1. It is more preferred that X 2 is a cyclic thioamido group (i.e., a mercapto-substituted nitrogen-containing hetero-ring, e.g., a 2-mercaptothiadiazole, 3-mercapto-1,2,4-triazole, 5-mercaptotetrazole, 2-mercapto-1,3,4-oxadiazole or 2-mercaptobenzoxazole group) or a nitrogen-containing heterocyclic group (e.g., benzotriazole, benzimidazole, indazole). Hydrogen is most preferred as R 23 and R 24 . A carbonyl group is most preferred for G in formula (N-II). It is preferred that compounds of formula (N-II) contain silver halide adsorption accelerating groups. Particularly preferred silver halide adsorption accelerating groups are the mercapto, cyclic thioamide and nitrogen-containing heterocyclic groups described above formula (N-I). Specific examples of compounds represented by formula (N-II) are as follows, but the invention is not to be construed as being limited to these compounds. ##STR10## Methods for synthesis of the compounds represented by formula (N-II) are disclosed in, e.g., the patents noted in Research Disclosure No. 15,162 (published November 1976, pages 76 to 77), No. 22,534 (published January 1983, pages 50 to 54) and No. 23,510 (published November 1983, pages 346 to 352) and U.S. Pat. Nos. 4,080,207, 4,269,924 and 4,276,364. Any layer ma contain the compounds represented by formulae (N-I) and (N-II) in the photographic photo-sensitive material in the present invention, but preferably these compounds are present in a silver halide emulsion layer. There are no particular restrictions concerning the amounts used but an amount in the range of from about 1×10 -8 moles to about 1×10 -2 moles per 1 mole of silver in the silver halide emulsion layer is useful and preferably the amount is from 1×10 -7 moles to about 1×10 -3 moles per 1 mole of silver. Preferably photographic material also contains at least one of the following compounds in order to heighten the effects of the nucleating agent of the invention still further. Hydroquinones (e.g., the compounds disclosed in U.S. Pat. Nos. 3,227,552 and 4,279,987); chromans (e.g., the compounds disclosed in U.S. Pat. No. 4,268,621, JP-A-54-103031 and Research Disclosure No. 18264 (1979)); quinones (e.g., the compounds disclosed in Research Disclosure No. 21206 (1981)); amines (e.g., the compounds disclosed in U.S. Pat. No. 4,150,993 and JP-A-58-174757); oxidizing agents (e.g., the compounds disclosed in JP-A-60-260039 and Research Disclosure No. 16936 (1978)); catechols (e.g., the compounds disclosed in JP-A-55-21013 and JP-A-55-65944); compounds which release nucleating agents at the time of development (e.g., the compounds disclosed in JP-A-60-107029); thioureas (e.g., the compounds disclosed in JP-A-60-95533); and spirobisindans (e.g., the compounds disclosed in JP-A-55-65944). Preferably, nucleating agents represented by formula (N-I) are used in the present invention and the following embodiments are more preferred and embodiment (8) is the most preferred. (1) The case where a silver halide adsorption accelerating group represented by X 1 is included as a substituent. (2) The case in (1) above where the silver halide adsorption accelerating group represented by X 1 in (1) above is a thioamido or heterocyclic mercapto group or a nitrogen-containing hetero-ring which forms imino silver. (3) The case in (2) above where the hetero-ring completed by Z is quinolinium, isoquinolinium, naphthopyridinium or benzothiazolium. (4) The case in (2) above where the hetero-ring completed by Z is quinolium. (5) The case in (2) above where an alkynyl group is contained in R 1 , R 2 or Z. (6) The case in (5) above where R 1 is a propargyl group. (7) The case in (2) above where a thiourethane group constitutes the thioamido group for X 1 or a mercaptotetrazole group constitutes the heterocyclic mercapto group for X 1 . (8) The case in (6) above where R 1 forms a ring by bonding with a hetero-ring that is completed by Z. When a nucleating agent represented by formula (N-II) is used, the following embodiments are more preferred and embodiment (6) is the most preferred. (1) The case where a silver halide adsorption accelerating group represented by X 2 is included as a substituent. (2) The case in (1) above where the silver halide adsorption accelerating group represented by X 2 in (1) above is a heterocyclic mercapto group or a nitrogen-containing hetero ring which forms imino silver. (3) The case in (2) above where the group represented by G-R 22 is formyl. (4) The case in (3) above where R 23 and R 24 are hydrogen. (5) The case in (3) above where R 21 is an aromatic group. (6)The case in (2) above where the heterocyclic mercapto group represented by X 2 is a 5-mercaptotetrazole or 5-mercapto-1,2,4-triazole. The compounds of formulae (N-I) and (N-II) may be used alone or in combination. Although they do not substantially possess the functions of nucleating agents, "nucleation accelerators" may be used for the purpose of promoting the nucleating agent action in order to increase the maximum density of the direct positive image and/or shorten the time needed to obtain a set direct positive image density. Specific examples of nucleation accelerators that are useful in the invention are as follows, but the invention is not to be construed as being limited to these examples. ##STR11## Also, a sensitizing dye may be used for the purpose of spectral sensitization. Suitable sensitizing dyes include cyanine dyes having a wavelength absorption maximum on silver halide of 590 nm or less, represented by formula (III): ##STR12## wherein Z 11 and Z 12 may be the same or different and represent atomic groups necessary for forming 5- to 6-membered nitrogen-containing heterocyclic nuclei and I 11 is 0 or 1. It is preferred that I 11 is 0, Z 11 and Z 12 may be the same or different and each represents thiazole, benzothiazole, naphthothiazole, dihydronaphthothiazole, selenazole, benzoselenazole, naphthoselenazole, dihydronaphthoselenazole, oxazole, benzoxazole, naphthoxazole, benzimidazole, naphthoimidazole, pyridine, quinoline, imidazo[4,5-b]quinoxaline or 3,4-dialkylindolenine; and when I 11 is 1, the nuclei represented by Z 11 include thiazoline, thiazole, benzothiazole, selenazoline, selenazole, benzoselenazole, oxazole, benzoxazole, naphthoxazole, imidazole, benzimidazole, naphthoimidazole and pyrroline, and the nuclei represented by Z 12 include oxazoline, oxazole, benzoxazole, naphthoxazole, thiazoline, selenazoline, pyrroline, benzimidazole or naphthoimidazole. These nitrogen-containing heterocyclic nuclei represented by Z 11 and Z 12 may have one or more substituents. Examples of preferred substituents include lower alkyl groups (which may be branched and which may also include substituent groups (e.g., hydroxyl groups, halogen atoms or aryl, aryloxy, arylthio, carboxyl, alkoxy, alkylthio or alkoxycarbonyl groups) and are preferably alkyl groups with not more than 10 carbon atoms, e.g., methyl, ethyl, butyl, chloroethyl, 2,2,3,3-tetrafluoropropyl, hydroxyl, benzyl tolylethyl, phenoxyethyl, phenylthioethyl, carboxypropyl, methoxyethyl, ethylthioethyl, ethoxycarbonylethyl); or lower alkoxy groups (which may have further substituent groups). Examples of substituents include the same substituents for the alkyl groups above. More preferably they are alkoxy groups with 8 or less carbon atoms, e.g., methoxy, ethoxy, pentyloxy, ethoxymethoxy, methylthioethoxy, phenoxyethoxy, hydroxyethoxy, chloropropoxy); hydroxyl groups, halogen atoms, cyano groups, aryl groups (e.g., phenyl, tolyl, anisyl, chlorophenyl, carboxyphenyl), aryloxy groups (e.g., tolyloxy, anisyloxy, phenoxy, chlorophenoxy), arylthio groups (e.g., tolylthio, chlorophenylthio, phenylthio), lower alkylthio groups (which may be substituted with the same substituents for the above lower alkyl group). More preferably they are alkylthio groups with 8 or less carbon atoms (e.g., methylthio, ethylthio, hydroxylthio, carboxyethylthio, chloroethylthio or benzylthio groups); acylamino groups (preferably acylamino groups with 8 or less carbon atoms, e.g., acetylamino, benzoylamino, methanesulfonylamino or benzenesulfonylamino groups); carboxyl groups; lower alkoxycarbonyl groups (preferably alkoxycarbonyl groups with 6 or less carbon atoms, e.g., ethoxycarbonyl or butoxycarbonyl groups); perfluoroalkyl groups (preferably perfluoroalkyl groups with 5 or less carbon atoms, e.g., trifluoromethyl or difluoromethyl groups) and acyl groups (preferably acyl groups with 8 or less carbon atoms, e.g., acetyl, propionyl, benzoyl or benzenesulfonyl groups). Specific examples of nitrogen-containing heterocyclic nuclei represented by Z 11 and Z 12 include thiazoline, 4-methylthiazoline, thiazole, 4-methylthiazole, 4,5-dimethylthiazole, 4-phenylthiazole, benzothiazole, 5-methylbenzothiazole, 6-methylbenzothiazole, 5-ethylbenzothiazole, 5,6-dimethylbenzothiazole, 5-methoxybenzothiazole, 6-methoxybenzothiazole, 5-butoxybenzothiazole, 5,6-dimethoxybenzothiazole, 5-methoxy-6-methylbenzothiazole, 5-chlorobenzothiazole, 5-chloro-6-methylbenzothiazole, 5-phenylbenzothiazole, 5-acetylaminobenzothiazole, 6-propionylaminobenzothiazole, 5-hydroxybenzothiazole, 5-hydroxy-6-methylbenzothiazole, 5-ethoxycarbonylbenzothiazole, 5-carboxybenzothiazole, naphtho[1,2-d]thiazole, naphtho[2,1-d]thiazole, 5-methylnaphtho[1,2-d]thiazole, 8-methoxynaphtho[1,2-d]thiazole, 8,9-dihydronaphthothiazole, 3,3-diethylindolenine, 3,3-dipropylindolenine, 3,3-dimethylindolenine, 3,3,5-trimethylindolenine, selenazoline, selenazole, benzoselenazole, 5-methylbenzoselenazole, 6-methylbenzoselenazole, 5-methoxybenzoselenazole, 6-methoxybenzoselenazole, 5-chlorobenzoselenazole, 5,6-dimethylbenzoselenazole, 5-hydroxybenzoselenazole, 5-hydroxy-6-methylbenzoselenazole, 5,6-dimethoxybenzoselenazole, 5-ethoxycarbonylbenzoselenazole, naphtho[1,2-d]selenazole, naphtho[2,1-d]selenazole, oxazole, 4-methyloxazole, 4,5-dimethyloxazole, 4-phenyloxazole, benzoxazole, 5-hydroxybenzoxazole, 5-methoxybenzoxazole, 5-phenylbenzoxazole, 5-phenethylbenzoxazole, 5-phenoxybenzoxazole, 5-chlorobenzoxazole, 5-chloro-6-methylbenzoxazole, 5-phenylthiobenzoxazole, 6-ethoxy-5-hydroxybenzoxazole, 6-methoxybenzoxazole, naphtho[1,2d]oxazole, naphtho[2,1-d]oxazole, naphtho[2,3-d]oxazole, 1-ethyl-5-cyanobenzimidazole, 1-ethyl-5-chlorobenzimidazole, 1-ethyl-5,6-dichlorobenzimidazole, 1-ethyl-6-chloro-5-cyanobenzimidazole, 1-ethyl-6-chloro-5-trifluoromethylbenzimidazole, 1-propyl-5-butoxycarbonyl benzimidazole, 1-benzyl-5-methylsulfonylbenzimidazole, 1-allyl-5-chloro-6-acetylbenzimidazole, 1-ethylnaphtho[1,2-d]imidazole, 1-ethyl-6-chloronaphtho[2,3-d]imidazole, 2-quinoline, 4-quinoline, 8-fluoro-4-quinoline, 6-ethyl-2-quinoline, 6-hydroxy-2-quinoline and 6-methoxy-2-quinoline. R 11 and R 12 may be the same or different and each represents optionally substituted alkyl or alkenyl groups with 10 carbon atoms or less. Preferred substituents of alkyl and alkenyl groups include sulfo groups, carboxy groups, halogen atoms, hydroxyl groups, alkoxy groups with 6 carbon atoms or less, optionally substituted aryl groups with 8 carbon atoms or less (e.g., phenyl, tolyl, sulfophenyl, carboxyphenyl), heterocyclic groups (e.g., furyl, thienyl), optionally substituted aryloxy groups with 8 carbon atoms or less (e.g., chlorophenoxy, phenoxy, sulfophenoxy, hydroxyphenoxy), acyl groups with 8 carbon atoms or less (e.g., benzenesulfonyl, methanesulfonyl, acetyl, propionyl), alkoxycarbonyl groups with 6 carbon atoms or less (e.g., ethoxycarbonyl, butoxycarbonyl), cyano groups, alkylthio groups with 6 carbon atoms or less (e.g., methylthio, ethylthio), optionally substituted arylthio groups with 8 carbon atoms or less (e.g., phenylthio, tolylthio), optionally substituted carbamoyl groups with 8 carbon atoms or less (e.g., carbamoyl, N-ethylcarbamoyl) and acylamino groups with 8 carbon atoms or less (e.g., acetylamino, methanesulfonylamino). The groups may have one or more substituents. Specific examples of the groups represented by R 11 and R 12 include methyl, ethyl, propyl, allyl, pentyl, hexyl, methoxyethyl, ethoxyethyl, phenethyl, tolylethyl, sulfophenethyl, 2,2,2-trifluoroethyl, 2,2,3,3-tetrafluoropropyl, carbamoylethyl, hydroxyethyl, 2-(2-hydroxyethyoxy)ethyl, carboxymethyl, carboxyethyl, ethoxycarbonylmethyl, sulfoethyl, 2-chloro-3-sulfopropyl, 3-sulfopropyl, 2-hydroxy-3-sulfopropyl, 3-sulfobutyl, 4-sulfobutyl, 2-(2,3-dihydroxypropyloxy)ethyl and 2-[2-(3-sulfopropyloxy)ethoxy]ethyl. R 13 and R 15 represent hydrogen. Also, R 13 may link with R 11 or R 15 may link with R 12 to form a 5- or 6-membered ring. R 14 represents hydrogen or a lower alkyl group (which may be substituted, e.g., methyl, ethyl, propyl, methoxyethyl or phenethyl, and is preferably an alkyl group with not more than 5 carbon atoms). X 11 represents an acid anion radical (residue) necessary for charge balance. m 11 represents 0 or 1 and in the case of an intramolecular salt, m 11 is 0. Preferred sensitization dyes represented by formula (III) are dyes in which I 11 in the formula is 1; Z 11 is a heterocyclic-nucleus-forming atomic group such as oxazole, benzoxazole or naphthoxazole, Z 12 is a heterocyclic-nucleus-forming atomic group such as benzimidazole or naphthoimidazole (where the heterocyclic nuclei represented by Z 11 and Z 12 may possess one or more substituents as noted above, and electron-attracting substituents are preferred when Z 12 is a benzimidazole or naphthoimidazole nucleus), at least one of R 11 and R 12 is a group possessing a sulfo, carboxyl or hydroxyl group and R 14 is hydrogen. Among the sensitization dyes representable by formula (III), it is particularly preferred that where Z 11 is an atomic group that forms a benzoxazole nucleus, Z 12 is an atomic group that forms a benzimidazole nucleus, at least one of R 11 and R 12 possesses a sulfo or carboxy group, R 14 is hydrogen and I 11 is 1. The heterocyclic nuclei represented by Z 11 and Z 12 may have one or more substituents such as noted above and particularly preferred substituents include chlorine atoms, fluorine atoms, cyano groups, alkoxycarbonyl groups with 5 carbon atoms or less, acyl groups with 7 carbon atoms or less and perfluoroalkyl groups with 4 carbon atoms or less such as trifluoromethyl in the case of a benzimidazole nucleus; and optionally substituted phenyl groups with 8 carbon atoms or less, alkyl groups with 5 carbon atoms or less, alkoxy groups with 5 carbon atoms or less, acylamino groups with 5 carbon atoms or less, carboxyl groups, alkoxycarbonyl groups with 5 carbon atoms or less, benzyl groups, phenethyl groups and chlorine atoms in the case of other heterocyclic nuclei. Specific examples of compounds represented by formula (III) are as follows, but the present invention is not to be construed as being limited thereto. ##STR13## The compounds represented by formula (III) are known compounds and can be synthesized by the methods described in, e.g., JP-A-52-104917; JP-B-48-25652 or JP-B-57-22368; F. M. Hamer, The Chemistry of Heterocyclic Compounds, Vol. 18, "The Cyanine Dyes and Related Compounds", A. Weissberger ed., (Interscience, New York, 1964 or D. M. Sturmer, The Chemistry of Heterocyclic Compounds, Vol. 30, A Weissburger and E. C. Taylor ed., (John Willy, New York), p. 441. In the present invention, the compounds represented by formula (III) are used in an amount of generally from 1×10 -6 to 1×10 -1 mol and preferably from 1×10 -4 to 1×10 -2 mol per mol of the silver. The non-prefogged internal latent image type silver halide emulsion that is used in the present invention is an emulsion containing a silver halide in which the surfaces of the grains is not prefogged, and latent images are mainly formed in the interior of its grains. In more detail, the emulsion is one such that, when a determined amount of silver halide emulsion is coated on a transparent support, the maximum density, as determined by normal densitometry procedure, on exposure for a set time of 0.01 to 10 seconds and development for 6 minutes at 20° C. in the developing solution A (internal development solution) described below, is preferably at least 5 times and more preferably at least 10 times greater than the density obtained on coating of the same amount, exposure in the same manner and development for 5 minutes at 18° C. in the developing solution B (surface development solution) described below. ______________________________________Metol 2.5 gL-Ascorbic acid 10 gNaBO.sub.2.4H.sub.2 O 35 gKBr 1 gWater to make 1 lInternal developing solution A:Metol 2 gSodium sulfite (anhydrous) 90 gHydroquinone 8 gSodium carbonate (monohydrate) 52.5 gKBr 5 gKI 0.5 gWater to make 1 l______________________________________ Specific examples of these latent image type emulsions include conversion type silver halide emulsions and core/shell type silver halide emulsions disclosed in British Patent 1,011,062 and U.S. Pat. Nos. 2,592,250 and 2,456,943. Examples of core/shell type silver halide emulsions include the emulsions disclosed in JP-A-47-32813, JP-A-47-32814, JP-A-52-134721, JP-A-52-156614, JP-A-53-60222, JP-A-53-66218, JP-A-53-66727, JP-A-55-127549, JP-A-57-136641, JP-A-58-70221, JP-A-59-208540, JP-A-59-216136, JP-A-60-107641, JP-A-60-247237, JP-A-61-2148, JP-A-61-3137, JP-B-56-18939, JP-B-58-1412, JP-B-58-1415, JP-B-58-6935, JP-B-58-108528, JP-A-62-194248, U.S. Pat. Nos.3,206,313, 3,317,322, 3,761,266, 3,761,276, 3,850,637, 3,923,513, 4,035,185, 4,395,478 and 4,504,570, European Patent 0017148 and Research Disclosure RD 16345 (November 1977). Typical silver halide emulsion compositions comprise mixed silver halides such as, silver chlorobromide, silver chloroiodobromide, and silver iodobromide in addition to silver chloride and silver bromide. The silver halide emulsions that are preferably used in the present invention are emulsions containing silver chloro(iodo)bromide, silver (iodo)chloride or silver (iodo)bromide, having a silver iodide content of 3 mol % or less and particularly 0 mol % or less. The silver halide grains have an average grain size (expressed as an average based on projected areas, taking sizes to be grain diameters in the case of spherical or near-spherical grains and to be edge lengths in the case of cubic grains) is preferably 0.1 μm to 2 μm, and an average grain size of 0.15 μm to 1 μm is particularly preferred. The grain size distribution may be broad or narrow but for the sake of improving aspects such as graininess or sharpness preferably is `monodisperse` silver halide emulsion with a narrow grain size distribution, such that 90% or more, or preferably 95% or more of all the grains (in terms of the weight of number of grains) is within ±40% (preferably within ±30%, and most preferably within ±20%) of the average grain size. In order that the photosensitive material may meet gradation requirements, monodisperse silver halide emulsions with two or more different grain sizes may be included in emulsion layers that have essentially the same color sensitivity or a plurality of grains that have the same size but differ in respect of speed may be mixed in one and the same layer or be provided as multi-layered coatings in different layers. Further, combinations of two or more different polydisperse silver halide emulsions or of a monodisperse emulsion and a polydisperse emulsion may be mixed or used as multi-layers. The silver halide grains used in the present invention may be regular crystal grains such as cubic, octahedral, dodecahedral, tetradecahedral, or irregular crystal grains such as a spherical, or grains having composite forms combining these crystal forms. The grains may also be tabular. In particular, an emulsion may be used in which tabular grains having a length/thickness ratio of 5 or more, and preferably 8 or more, occupy 50% or more of the total projected area of the grains. Emulsions composed of a mixture of these various forms may also be used. The silver halide emulsions that are employed in the present invention can be prepared in the presence of silver halide solvents. Silver halide solvents include the organic thioethers disclosed in U.S. Pat. Nos. 3,271,157, 3,531,289 and 3,574,628, JP-A-54-1019 and JP-A-54-158917 and the thiourea derivatives disclosed in JP-A-53-82408, JP-A-55-77737 and JP-A-55-2982. The silver halide emulsions used in the present techniques such as sulfur or selenium sensitization, reduction sensitization or noble metal sensitization, used alone or in combination for grain interiors or surfaces. As well as the sensitization dyes of the present invention, the photosensitive material used in the present invention may contain the sensitization dyes disclosed on pages 45 to 53 of JP-A-55-52050 (e.g., cyanine or merocyanine dyes) in order to increase its sensitivity. These sensitization dyes may be used alone or combinations thereof may be employed, combinations in particular being used for the purpose of supersensitization. Together with sensitization dyes, the emulsions may also contain dyes which do not themselves have a spectral sensitizing action or substances which absorb essentially no visible light but which display supersensitization. Apart from the dyes noted above, combinations of sensitization dyes and substances as that display strong color sensitization are disclosed in Research Disclosure Vol. 176, 17643 (published December 1978), page 23, items IV A to J. The sensitization dyes can be added at any stage of photographic emulsion manufacture or can be added at any stage up to immediately prior to coating the emulsion after the beginning of production. Examples in the former case are addition at the time of grain formation and addition at the time of physical ripening or chemical ripening. Water-soluble dyes may be included in emulsion layers or other hydrophilic colloidal layers of the present invention as filter dyes or for preventing irradiation or a variety of other purposes. Dyes whose essential absorption of light is mainly in the 350 to 600 nm region and which serve to lower photographic sensitivity or to improve safety with respect to safe lights are useful as filter dyes. Depending on the object, these dyes may be added to an emulsion layer or may be added together with mordant dyes above the silver halide emulsion layer, i.e., to a insensitive hydrophilic colloid layer that is further than the silver halide emulsion layer from the support. The amount added varies depending on the molar absorbance coefficient of the dye, but is normally 1×10 -2 g/m 2 to 1 g/m 2 and preferably 50 to 500 mg/m 2 . Specific examples of dyes are described in detail in JP-A-63-64039. The photosensitive material of the present invention may include therein a variety of compounds for preventing fogging or stabilizing photographic properties during manufacture, storage or photographic processing of the material. That is, one may add many compounds that are known as antifoggants or stabilizers, examples including azoles, e.g., benzothiazolium salts, nitroindazoles, chlorobenzimidazoles, bromobenzimidazoles, mercaptothiazoles, mercaptobenzothiazoles, mercaptothiadiazoles, aminotriazoles, benzothiazoles and nitrobenzotriazoles; mercaptopyrimidines; mercaptotriazines; thioketo compounds such as oxazolinethione; azaindenes, e.g., triazaindenes, tetraazaindenes (especially 4-hydroxy-substituted (1,3,3a,7)tetraazaindenes) and pentaazaindenes; benzenethiosulfonic acid, benzenesulfinic acid and benzenesulfonic acid amides. In order to improve sensitivity, improve contrast or accelerate development, one may include in the photographic emulsion layer of the photographic material of the present invention developing agents such as polyalkylene oxides or derivatives such as ethers, esters or amines thereof, thioether compounds, thiomorpholines, quaternary ammonium salt compounds, urethane derivatives, urea derivatives, imidazole derivatives, dihydroxybenzenes and 3-pyrazolidones. Among these, dihydroxybenzenes (hydroquinone, 2-methylhydroquinone, catechol) and 3-pyrazolidones (1 phenyl-3-pyrazolidone, 1-phenyl 4-methyl-4-hydroxymethyl-3-pyrazolidone) are preferred and normally not more than 5 g/m 2 thereof is used. 0.01 to 1 g/m 2 is more preferred in the case of dihydroxybenzenes and 0.01 to 0.2 g/m 2 is preferred in the case of 3-pyrazolidones. Inorganic or organic hardeners may be included in the photographic emulsion or insensitive hydrophilic colloid of the present invention. For example, active vinyl compounds (e.g., 1,3,5-triacryloyl-hexahydro-s-triazine, bis(vinylsulfonyl)methyl ether, N,N'-methylenebis-[β-(vinylsulfonyl)propionamide]), active halogen compounds (e.g., 2,4-dichloro-6-hydroxy-s-triazine), mucohalogenic acids (e.g., mucochloric acid), N-carbamoylpyridinium salts (e.g., (1-morpholinocarbonyl-3-pyridinio)methanesulfonate), haloamidinium salts (e.g., 1-(1-chloro-1-pyridinomethylene)pyrrolidinium, and 2-naphthalenesulfonate) may be used alone or in combination. Among such substances, the active vinyl compounds disclosed in JP-A-53-41220, JP-A-53-57257, JP-A-59-162546 and JP-A-60-80846 and the active halogen compounds disclosed in U.S. Pat. No. 3,325,287 are preferred. The photographic emulsion layers or other hydrophilic colloid layers of photosensitive material produced by means of the present invention may contain a variety of surfactants to serve as coating aids or for the purpose of, e.g., prevention of static, improvement of sliding characteristics, improvement of emulsification dispersion, prevention of adhesion or improvement of photographic characteristics (e.g., developing acceleration, increase in contrast, increase in sensitivity). Examples of useful surfactants include nonionic surfactants such as saponins (steroid type); alkylene oxide derivatives (e.g., polyethylene glycol, polyethylene glycol/polypropylene glycol condensates, polyethylene glycol alkyl ethers or alkylaryl ethers, polyethylene glycol esters, polyethylene glycol sorbitan esters, polyalkylene glycol alkylamines or amides, silicone-polyethylene oxide adducts), glycidol derivatives (e.g., alkenylsuccinic acid polyglyceride, alkylphenol polyglyceride), polyhydric alcohol fatty acid esters and alkyl esters of sugars; anionic surfactants containing carboxyl, sulfo, phospho, sulfate, or phosphate groups, e.g., alkylcarboxylates, alkylsulfonates, alkylbenzenesulfonates, alkylnaphthalenesulfonates, alkylsulfates, alkylphosphates, N-acyl-N-alkyltaurines, sulfosuccinates, sulfoalkylpolyoxyethylene alkylphenyl ethers and polyoxyethylenealkyl phosphates; amphoteric surfactants such as amino acids, aminoalkylsulfonic acids, aminoalkyl sulfates or phosphates, alkylbetaines and amine oxides; and cationic surfactants such as alkylamine salts, aliphatic or aromatic quaternary ammonium salts, heterocyclic quaternary ammonium salts such as pyridinium, imidazolium and phosphonium or sulfonium salts containing aliphatic or hetero-rings. It is preferred to use a fluorine-containing surfactant such as disclosed in, e.g., JP-A-60-80849 in order to prevent static. Matting agents such as silica, magnesium oxide, barium strontium sulfate, polymethyl methacrylate may be included in photographic emulsion layers or other hydrophilic colloid layers of the photographic photo-sensitive material of the present invention in order to prevent adhesion. A dispersion of a water-insoluble or sparingly-soluble synthetic polymer may be included in the photosensitive material that is used in the invention in order to improve physical film properties. For example, a polymer whose monomer components are alkyl(meth)acrylate, alkoxyalkyl(meth)acrylate or glycidyl (meth)acrylate alone or in combination, or combinations of these substances with acrylic acid or methacrylic acid can be used. Use of gelatin as a binder or protective colloid for the photographic emulsion is advantageous, but other hydrophilic colloids may also be used. For example, gelatin derivatives, graft polymers of gelatin with other macromolecular substances, proteins such as albumin or casein, cellulose derivatives such as hydroxyethylcellulose, carboxymethylcellulose, cellulose sulfate, sodium alginate, sugar derivatives such as starch derivatives, polyvinyl alcohol, polyvinyl alcohol partial acetate, poly-N-vinylpyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinylimidazole, polyvinylpyrazole and a large number of other hydrophilic synthetic polymers may be employed alone or in the form of copolymers. The gelatin employed may be lime-treated gelatin or acid-treated gelatin and one can also use the decomposition products of gelatin hydrolysis or enzymolysis. A polymer latex such as alkylacrylate may be included in silver halide emulsion layers used in the present invention. Materials such as cellulose triacetate, cellulose diacetate, nitrocellulose, polystyrene or polyethylene terephthalate may be used as a support for the photosensitive material of the present invention. For COM film in particular, use of a support with good electrical conductivity is preferred since it is important that the film have outstanding antistatic properties. A variety of known developing agents may be used to develop the photosensitive material of the present invention. In more detail, substances such as polyhydroxybenzenes, e.g., hydroquinone, 2-chlorohydroquinone, 2-methylhydroquinone, catechol or pyrogallol; aminophenols, e.g., p-aminophenol, N-methyl-p-aminophenol or 2,4-diaminophenol; 3-pyrazolidones, e.g., 1-phenyl-3-pyrazolidones, 1-phenyl-4,4-dimethyl-3-pyrazolidone, 1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone or 5,5-dimethyl-1-phenyl-3-pyrazolidone; and ascorbic acids can be used alone or in combination. Specifically, use can be made of developing solutions such as described in U.S. Pat. No. 4,540,655. Primary aromatic amine developing agents, preferably p-phenylenediamine developing agents can be used to obtain dye images in the presence of dye-forming couplers. Specific examples include 4-amino-3-methyl-N,N-dimethylanilinehydrochloride, N,N-diethyl-pphenylenediamine, 3-methyl-4-amino-N-ethyl-N-β-(methanesulfoamido)ethylaniline, 3-methyl-4-amino-N-ethyl-N-(β-sulfoethyl)aniline, 3-ethoxy-4-amino-N-ethyl-N-(β-sulfoethyl)aniline and 4-amino-N-ethyl-N-(β-hydroxyethyl)aniline. Developing agents such as these may be included in alkaline processing compositions (processing elements) or be included in suitable layers of photosensitive elements. If DRR compounds are used in the present invention, these may be any compounds as long as they can be cross-oxidized and they can be used with any type of silver halide developing agent. Substances such as sodium sulfite, potassium sulfite, ascorbic acid or reductones (e.g., piperidinohexose reductone) may be included in the developing solution as preservatives. The photosensitive material of the present invention permits production of direct positive images by development using a surface developing solution. A surface developing solution is one with which developing processes are essentially brought about by fogging nuclei and latent image on the surfaces of silver halide grains. Although it is preferable that no silver halide dissolving agent be included in the developing solution, such a dissolving agent (e.g., a sulfite) may be included as long as it makes essentially no contribution to internal latent images prior to completion of silver halide grain surface development. The developing solution may contain as alkali agents or buffer agents in the form of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, trisodium phosphate or sodium metaborate. The amounts included of such agents are so selected that the developing solution pH is 10 to 12, preferably 10 to 11.5, and more preferably 10.0 to 11.0. A color developing accelerator such as benzyl alcohol may be included in the developing solution. For the purpose of lowering the minimum density of direct positive images, it is advantageous to further include in the developing solution a compound normally employed as an antifoggant, e.g., a benzimidazole such as 5-nitrobenzimidazole or a benzotriazole such as benzotriazole or 5-methylbenzotriazole. The present invention is now described in greater detail with reference to specific examples thereof, but the present invention is not to be construed as being limited thereto. Unless otherwise indicated, all parts, percents and ratios are by weight. EXAMPLE 1 An emulsion A was prepared by the following manner. Emulsion A An emulsion of octahedral silver bromide with an average grain diameter of 0.15 μm was produced by simultaneous addition, accompanied by vigorous stirring for 5 minutes at 75° C., of a potassium bromide aqueous solution and a silver nitrate aqueous solution to a gelatin aqueous solution in the presence of a 1,8-dihydroxy-3,6-dithiaoctane solvent. After adjustment of the solution's pAg to 8.20, to the emulsion produced was added 115 mg each of sodium thiosulfate and chloroauric acid (tetrahydrate) per 1 mole of silver and the emulsion was chemically sensitized with heating for 50 minutes at 75° C. The silver bromide grains thus produced were used as cores and were grown further by being treated for 40 minutes in the same precipitation environment as above but with control of the solution's pAg to 7.50, ultimately producing a monodisperse core/shell emulsion of cubic silver bromide grains with an average grain diameter of 0.25 μm. After water washing and desalting, to this emulsion was added 3.4 mg each of sodium thiosulfate and chloroauric acid (tetrahydrate) per 1 mole of silver and chemically sensitized with heating for 60 minutes at 75° C., so giving an internal latent image type silver halide emulsion A. Emulsion A was divided into separate lots to which the amounts as indicated in Table 1 of compound (a) of the present invention and comparative compounds were added. Additions were also made of 2.5×10 -6 moles/l mole Ag of the illustrated compound (N-I-15) as a nucleating agent, of 1.2×10 -3 moles/l mole Ag of the illustrated compound (III-12) as a sensitization dye and of 4-hydroxy-6-methyl-1,3,3,3a-tetraazaindene and 5-methylbenzotriazole as stabilizers and 1,3-divinylsulfonyl-2-propanol as a hardening agent. Further, to a gelatin solution for use as a surface protection layer was added barium strontium sulfate with an average grain diameter of 1.0 μm as a matting agent, 50 mg/m 2 of hydroquinone, 20 mg/m 2 of a compound of the structural formula (1) given below and as coating aids of sodium p-dodecylbenzenesulfonate and a surfactant with the structural formula (2) given below. Samples 1 to 6 were prepared by coating this solution together with an emulsion by a simultaneous coating process to give an Ag quantity of 1.6 g/m 2 on a polyethylene terephthalate film. ##STR14## These samples were exposed for 1×10 -4 seconds with a 3.75×10 5 lux xenon flash light via a continuous wedge. Positive images were produced by development of the various samples for 30 seconds at 35° C. using Blowstar Plus developing solution (produced by Kodak) and stopping, fixing and washing by normal procedure. The results are indicated in Table 1. In the table, Dmax indicates the maximum density of reversal image, Dmin the minimum density and Sp-df the mid point speed, which is defined as the log E value giving the density (Dmax+Dmin)/2. The reference value is so selected that the speed is higher as the value of log E is greater. Δlog E 0.2 is defined as the speed amplitude since it defines the difference between the reversal speed that gives a density of Dmin+0.2 and the rereversal negative speed that gives a density of Dmin+0.2, as the difference of log E values. As is clear from the definition, a large speed amplitude signifies that re-reversal negatives are suppressed. It is seen that in contrast to the Comparative Samples No. 2 to No. 5, with Sample 6 containing compound (a) according to the present invention there was hardly any change in Dmax, Dmin or Sp-df, and this sample provided good photographic performance and a marked reduction of re-reversal negative image formation. TABLE 1__________________________________________________________________________ Compound (a) or similar compound ResultsExample No. Type Amount Added* Dmin Dmax Sp-df ΔlogE.sub.0.2__________________________________________________________________________1 -- -- 1.00 0.05 1.84 1.182 Comparison II-1 7.8 × 10.sup.-4 2.00 0.06 1.52 1.203 " II-8 " 1.50 0.06 1.65 1.234 " II-2 " 1.60 0.06 1.67 1.315 " II-3 " 1.82 0.06 1.48 1.196 Invention Compound " 1.02 0.05 1.86 1.82 (a)__________________________________________________________________________ EXAMPLE 2 Coating and testing were conducted in the same manner as in Example 1 except that compound (a) was combined with the accelerators shown in Table 2. The results are shown in Table 3. The symbols and abbreviations :n the table have the same definitions as in Example 1. As is apparent from the results, joint use of compound (a) together with an accelerator provided good performance in that there is a marked reduction of rereversal negative formation without any loss of Dmax increase effects being caused by the accelerator, i.e., with hardly any change in Dmax or Sp-df. TABLE 2__________________________________________________________________________Sample Compound (a) Nucleating Agent Accelerator Sensitization DyeNo. Amount added* Type Amount added* Type Amount added* Type Amount__________________________________________________________________________ added*1 Comparison -- N-I-15 2.5 × 10.sup.-6 -- -- -- --1 " -- " " II-1 8.8 × 10.sup.-4 -- --3 " -- " " " " III-12 1.2 × 10.sup.-34 Invention 7.8 × 10.sup.-4 " " -- -- -- --5 " " " " II-1 8.8 × 10.sup.-4 -- --6 " " " " " " III-12 1.2 × 10.sup.-37 " 5.2 × 10.sup.-3 " " -- -- -- --8 " " " " II-1 8.8 × 10.sup.-4 -- --9 " " " " " " III-12 1.2 × 10.sup.-3__________________________________________________________________________ *moles/1 mole Ag TABLE 3______________________________________Sample No. Dmin Dmax Sp-df ΔlogE.sub.0.2______________________________________1 Comparison 0.15 0.92 1.84 1.182 " 0.17 2.47 1.00 0.793 " 0.05 2.41 1.87 1.624 Invention 0.10 0.91 1.83 1.505 " 0.13 2.49 1.01 1.106 " 0.05 2.43 1.89 2.017 " 0.07 0.90 1.83 1.708 " 0.09 2.45 1.00 1.309 " 0.05 2.40 1.89 2.30______________________________________ EXAMPLE 3 An emulsion B was prepared by the following manner. Emulsion B An emulsion of octahedral silver bromide with an average grain diameter of 0.15 μm was produced by simultaneous addition, accompanied by vigorous stirring for 5 minutes at 75° C., of a potassium bromide aqueous solution and a silver nitrate aqueous solution to a gelatin aqueous solution in the presence of a thioether. After adjustment of the solution's pAg to 8.20, to the emulsion produced was added 38 mg each of sodium thiosulfate and chloroauric acid (tetrahydrate) per 1 mole of silver and the emulsion was chemically sensitized with heating for 50 minutes at 75° C. The silver bromide grains thus produced were used as cores and were grown further by being treated for 40 minutes in the same precipitation environment as above but with control of the solution pAg values to 8.20 and 7.70 in different batches, ultimately producing monodisperse emulsions of octahedral and tetradecahedral core/shell silver bromide grains with an average grain diameter of 0.25 μm. After water washing and desalting, to the emulsions were added 6.0 mg each of sodium thiosulfate and chloroauric acid (tetrahydrate) per 1 mole of silver, and the emulsion was chemically sensitized by heating for 60 minutes at 75° C., giving internal latent image type silver halide emulsions B-1 and B-2. The proportion of the total grain planes that were 100 planes in the grains in each emulsion was determined by the method described in the Journal of Imaging Science, 29:165 (1985). The other planes were (111) planes. ______________________________________Emulsion Proportion occupied by 100 planes (%)______________________________________B-1 85B-2 15______________________________________ On testing in the same manner in Examples 1 to 2 but using the above noted Emulsions B-1 and B-2 instead of Emulsion A, results like those in Examples 1 to 2 were obtained. It was thus found that in the case of octahedral and tetradecahedral grains too, samples containing compound (a) of the present invention provided excellent direct positive characteristics with much greater reduction of re-reversal negative formation than comparison samples. EXAMPLE 4 The samples used in Examples 1 to 3 were exposed in the same manner as in Example 1. Following this they were subjected to development for 30 seconds at 35° C. using the development solutions noted below, and stopping, fixing and washing by normal procedure resulted in excellent positive characteristics like those achieved in Examples 1 to 3. ______________________________________Developing Solution______________________________________FR Company FR Data Com-Pak NegativeALTA Company Datagraphix Auto Pos Chem Kit______________________________________ It will be appreciated from this that the method for processing silver halide photographic materials of the present invention to produce direct positives provides superior results by use of the present invention processing solutions. While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.
A method for forming a direct positive image by the steps of: (a) imagewise exposing a photosensitive material comprising a support having thereon at least one light-sensitive silver halide emulsion layer containing non-prefogged silver halide grains capable of forming an internal latent image; at least one of the light-sensitive emulsion layer or the other hydrophilic colloidal layer of the photosensitive material containing the following compound (a): ##STR1## (b) developing the exposed material in the presence of a developing agent and at least one nucleating agent; and (c) at least one of fixing and bleaching said developed photosensitive material to form a positive image. When used for making computer output images, the method according to the present invention provides rapid and stable formation of direct positive images with a high Dmax and a low Dmin, and prevents re-reversal negative formation during high illuminance exposure.
8
FIELD OF THE INVENTION This invention relates to dimensionally stable filter structures formed from thermoplastic fibers, and in particular to such filter structures having functional particulate matter incorporated therein. BACKGROUND OF THE INVENTION Filter structures formed from thermoplastic fibers and having a functional particulate matter incorporated therein may be used for a variety of purposes. Such filter structures containing activated carbon have been used to adsorb noxious or harmful gases. Other activated particulates may be used depending on the function of the filter. For example, a biocide may be incorporated into a thermoplastic filter structure for the destruction of microbes passing through the filter. The variety of particulate matter and the functions associated therewith are extensively documented and are too extensive to list individually herein. Examples of activated carbon filters for gas masks are disclosed in U.S. Pat. Nos. 4,981,501 and 4,992,084. These patents disclose a three dimensional carrier framework for activated carbon particles having a diameter from 0.1 to 1 mm. The carrier framework is said to be composed of wires, monofilaments or stays, the distance between the components being at least twice as great as the diameter of the adsorbent particles. A large pore reticulated polyurethane foam is specifically disclosed as a carrier framework for granular adsorbent particles. These patents also disclose that the adsorbent particles can be affixed to heterofilic fibers having two coaxially arranged components wherein one component has a lower melting point than the other. However, no method for preparing a dimensionally stable carrier framework from such heterofilic fibers is disclosed. It would be desirable to provide a dimensionally stable filter structure from thermoplastic fibers and an active particulate matter in which the carrier framework for the structure also carries a fibrous filter material in addition to the particulate filter material. Such a filter structure could provide greater surface area for attachment of particulate matter. SUMMARY OF THE INVENTION This invention relates to a particulate filter structure having a high degree of dimensional stability and including a stable three dimensional framework of relatively larger denier composite fibers, thermoplastic fibers of relatively smaller denier dispersed throughout and bonded to the framework, and an active particulate matter distributed within the fibrous framework and entrapped in interstices and bonded to at least the smaller denier thermoplastic fibers. The larger denier fibers maintain the stability and permeability of the filter structure, which filter structure substantially is formed of the smaller denier fibers and the particulate matter. The structural fibers comprise about ten percent of less of the total weight of the filter structure. The larger denier fibers should have a denier of at least about 30 dpf and should comprise a relatively higher melting component and a relatively lower melting component. The lower melting component bonds the fibers of the framework at the cross-over points. The smaller denier fibers should have a denier of less than about 30 dpf and are dispersed throughout and bonded to the framework to immobilize the thermoplastic fibers and to provide a surface for attachment of active particulate matter. The active particulate matter is bonded to at least the smaller denier thermoplastic fibers. In a more specific embodiment, the small and large denier fibers are formed of the same material and are sheath/core heterofilament fibers having a NYLON (polyamide) sheath and a polyester core. A filter structure formed from such larger and smaller denier heterofilaments can be made having a thickness of from about 1.0 mm to 250 mm. The particulate matter can have a nominal particle diameter from 0.1 micron to 5 mm depending on the selection of the framework composite fibers and the smaller denier thermoplastic fibers. The method for preparing such a particulate filter structure comprises preparing a framework of the relatively larger denier composite fibers having a denier of 30 dpf or greater, and thermally bonding these fibers at the cross-over points. Smaller denier thermoplastic fibers are dispersed into the framework and these fibers have a denier of less than about 30. The smaller denier fibers are immobilized onto the framework and a particulate matter is dispersed onto the framework and thermally bonded to at least the smaller denier fibers. The smaller denier fibers can be dispersed into the framework by hydro-entanglement or air-entanglement or some other suitable method. Alternatively, a web of relatively small denier thermoplastic fibers can be formed and larger denier fibers can be integrated into the smaller denier web to provide dimensional stability. In another specific method, a slurry of large and small denier fibers is placed into a mold and the solvent is removed to form a filter structure. Activated particulate matter may be included in the slurry or may be added after the filter structure is formed. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a representation of a cross-section through a filter structure of the present invention. FIG. 2 is a representation of a cross-section through a representative thermoplastic fiber of the present invention. FIG. 3 is a representation of a portion of the filter structure of FIG. 1 showing bonding of the fibers in the filter structure and bonding the particulate matter to the fibers of the filter structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates broadly at 10 a representation of a cross-section through a portion of the filter structure of the invention claimed herein. The filter structure includes a stable framework of relatively larger denier composite structural fibers 12 that are thermally bonded at the cross-over points 14. By the term "structural fibers" is meant fibers of relatively larger denier that may be used to support a filter or fabric structure. These structural fibers have a denier of at least about 30 dpf. The structural fibers may range in denier from about 30 dpf to 10,000 dpf or larger depending on the stiffness desired for providing a framework that is resistant to compression and is otherwise dimensionally stable and the size of the functional particulate 16 that is chosen. The composite fibers should be present in an amount sufficient to provide a structure to which may be bonded the relatively smaller denier fibers 18. The composite fibers 12 have a higher melting component and a lower melting component. The higher melting component has a melting point at least about 20° C. higher than the relatively lower melting component. When heated above the melting point of the lower melting component, but below the melting point of the higher melting component, the lower melting component bonds the fibers of the framework together without affecting the structural integrity of the framework that is provided by the higher melting component. Composite fibers suitable for use as structural fibers in the practice of the invention include bi-component fibers in which the higher and lower melting components are arranged in a side-by-side relationship, or heterofilament fibers having either a concentric or eccentric sheath/core arrangement with the high melting component forming the core and the lower melting component forming the sheath. The term "heterofilaments" as used herein refers to both staple fiber and to continuous filament, unless otherwise specified. The term "fiber" as used herein also refers to both cut staple and to continuous filament, unless otherwise specified. In side-by-side fibers the two components, one higher melting and one lower melting, are simultaneously extruded through single orifice to form a fiber having two halves. In the concentric sheath/core arrangement, a higher melting component forms a core centered axially within a lower melting sheath. In the eccentric sheath/core arrangement, the higher melting component is not centered axially of the fiber. Composite fibers are also sometimes referred to as bicomponent fibers. Composite fibers having a lower melting polyamide component and a higher melting polyester component have a beneficial application in the practice of the invention. For example, a sheath/core heterofilament (FIG. 2) having a nylon sheath with a melting point from about 175°-185° C. and a polyester core with a melting point of from about 240°-256° C. has a beneficial use in the practice of the present invention. FIG. 2 is a representation of a cross-section through a heterofilament 20. Heterofilament fiber 20 is representative of the many types of composite manufactured fibers that may be used for the framework or for attachment of the active particulate of the filter structure shown at 10 in FIG. 1. Fiber 20 is illustrated as a concentric sheath-core heterofilament fiber in which the sheath and the core each comprise about 50% of the cross-sectional area of the fiber. A range of area of the fiber occupied by the sheath is contemplated to be from about 20 to about 80%. The fiber has a lower melting nylon sheath 22 and a higher melting polyester core 24. The sheath should have a melting point that is at least about 20° C. below the melting point of the core and should occupy about half the cross-section of the fiber to provide strong thermal bonding of the fiber structure without adversely affecting the integrity of the core. The core provides strength and integrity to the filter structure. The framework of relatively large denier structural fibers 12 of the filter structure of the invention all include composite manufactured fibers as described above, having a lower melting component for thermal bonding of the structure at cross over points 14 and for immobilizing relatively smaller denier fibers 18. The skilled artisan should recognize that there are a wide variety of composite fibers having a higher melting component and a lower melting component that are suitable for the practice of the invention and that a heterofilament fiber having a polyamide sheath and a polyester core is but one of the broad array of fibers available. The composite fibers 12 may also be in a wide variety of forms including crimped and non-crimped cut staple fibers, short cut staple, continuous filaments or blends thereof. Smaller denier thermoplastic fibers 18 of the filter structure 10 are immobilized on the framework of larger denier fibers and provide, in addition to the particulate matter, active filtration of liquids and gases. These smaller denier fibers also greatly increase the surface available for immobilizing the functional particulates. These smaller denier fibers can range in denier from about 1 to 30 dpf. Smaller denier staple fibers and short cut staple are particularly useful in the filter structure of the invention, although continuous filaments are also contemplated. Fibers 18 should be present in an amount sufficient to immobilize the particulate matter and to provide a desired filtration at an acceptable pressure drop across the filter. The smaller denier thermoplastic fibers can be immobilized in the framework of larger denier fibers through the application of heat. Care should be exercised to avoid fusing the smaller fibers into a mass that could adversely impact pressure drop across the filter or otherwise reduce filter efficiency. Useful in the practice of the invention will be smaller denier fibers that have the same components as the composite structural fibers forming the framework. For example, if sheath/core heterofilaments of nylon and polyester are used to form the framework, then it is useful for bonding the structure and for immobilizing the smaller diameter fibers and the particulate matter if the smaller denier fibers are also sheath/core heterofilaments of polyamide and polyester having similar melting points. This similarity in melting points simplifies bonding of the filter framework, bonding of the smaller diameter fibers to the framework, and bonding of the particulate matter to the filter structure. Bonding and immobilization of the smaller denier fiber to the larger denier fiber, and fusing of the particulate matter to the larger and smaller denier fibers, is much the same as described herein above with respect to the bonding the larger denier composite fibers to form a framework. FIG. 3 is a greatly enlarged representation of particulate matter 16 immobilized within a framework of larger denier and smaller denier fibers 12 and be, respectively. The smaller denier fibers are immobilized on the framework of larger denier fibers at numerous points 26. The particles are fused primarily to the smaller denier fibers at numerous points 28, and may also be bonded to the larger denier fibers as shown at 30. As can be seen from FIG. 3, the filter structure is a cage-like structure in which particulate matter may be entrapped and substantially precluded from migrating. Fusing of the particle to the individual fibers desirably is localized in that the fiber does not form a film over the particle or otherwise substantially reduce the surface area of the particle available for contact with a liquid or gas stream moving through the filter structure. The particulate matter may be selected from a wide variety of substances having some function that is desirably incorporated into a fibrous structure. One of the most common is activated carbon. Other types of functional particulate matter includes silica, zeolite, molecular sieve, clay, alumina, ion exchange resin, organic metal catalyst, metal oxide, biocide, fungicide, and virucide. For example, a fungitide particulate matter may be incorporated into a filter structure such as for an automobile climate control system to remove mildew and mildew odors from the circulated air. Biocides and virucides may be incorporated into filters for protection against microbial components. Particulate sizes may range from a small size of 0.1 micron for biocides and fungicides to 3 to 5 mm for other types of particulate matter, and vary in shape from irregular to circular cylinders up to about 50 mm in length. The foregoing list is intended to be representative of the wide variety of functional particulate matter available and not in limitation of the substances suitable for use in the practice of the present invention. The filter structures of the present invention may be produced by a variety of processes. For example, a slurry of the larger denier fibers and smaller denier fibers may be formed in a solvent of water, acetone or other suitable hydrocarbon and placed into a mold. Particulate matter may or may not be included in the slurry, as desired. The liquid component of the slurry is removed, typically by vacuum, and through-air heat may be applied to dry the filter structure. If particulate matter was present in the slurry, then heat may also be applied to bond the filter structure and to bond particulate matter to the fibers. Otherwise, the particulate matter is then distributed into the dried structure. Activated carbon beads can be heated prior to application so that localized bonding takes place on contact with the fibers of the filter structure. The fibers of the filter structure are thereafter bonded. Alternatively, the particulate matter may be distributed cold and the entire structure and particulate bonded in one step. For example, activated carbon beads may be fused to individual concentric sheath/core fibers of the filter structure of the invention by heating the particles above the melting point of the low melting sheath component of the fiber and then dispersing the particles into the filter structure. Activated carbon can also be applied cold and then heated for immobilization within the filter structure. Activated carbon particles and other inorganic oxides and hydrates have significantly lower specific heats than polymers and so heat quickly and result in localized fluidity of the polymer. A "spot weld" is produced with a thin, controlled layer of adhesive provided by the polymer that minimizes loss of surface area of the particle. The filter structure of the invention can also be formed using dry forming methods such as carding or air laying of staple fibers or forming a web of continuous filaments. A web of the relatively larger denier fibers can be formed first and the smaller denier fibers and particulate matter dispersed therein and immobilized. Alternatively, a web of the relatively smaller denier fibers can be formed and the larger denier fibers thereafter integrated into the web. Particulate matter can be applied and immobilized either before or after the larger denier fibers are integrated into the web to form the filter structure of the web. Also, the web can be formed from the relatively smaller denier fibers and the relatively larger denier fibers together, and particulate matter can be applied and immobilized either during or after the formation of the web. The particulate matter may be applied to the web from scatter coaters, engraved rolls, or screen conveyors. An inclined ramp may The particulate matter may be applied to the web from scatter coaters, engraved rolls, or screen conveyors. An inclined ramp may be used to spread the particulate matter and to enmesh the particulate matter within the web. Suitable methods for distributing particulate matter into a web are described in applicant's copending U.S. patent application U.S.S.N 07/977995 filed Nov. 18, 1992, abandoned. The invention has been described with reference to particular preferred embodiments as illustrated in the drawing. However, these embodiments should be considered illustrative of and not in limitation of the invention claimed herein. On the contrary, the invention includes all alternatives, modifications, and equivalents that may be included within the scope and spirit of the invention as defined by the appended claims.
A particulate filter structure and method for making the structure are disclosed. The structure includes a stable framework of relatively large denier fibers having a lower melting component and a higher melting component. The larger denier fibers have a denier of from about 30 dpf or more and are bonded by the lower melting component at the crossover points. Smaller denier fibers, which preferably are of the same composition as the larger denier fibers are immobilized onto the framework formed by the larger denier fibers by applying heat. Functional particulate such as activated carbon is immobilized primarily onto the smaller denier fibers, also by application of heat.
3
TECHNICAL FIELD OF THE INVENTION The present invention relates in general to utility meter apparatus which is remotely accessible to obtain utility usage data, and more particularly relates to an interface circuit for allowing data from a utility meter, nonutility equipment, or other associated equipment, to be input into another meter storage circuit which is accessible from a remote location. BACKGROUND OF THE INVENTION The past practice of employing personnel to travel a route to visually read utility meters has in some instances been discontinued, in favor of techniques which allow for remotely reading the usage data of different types of utility services. For example, one common practice for obtaining the water usage of a residential or business is to employ a special water meter device which stores the number of gallons used, and to connect such device to a telephone line. In this manner, the telephone line can be utilized by the water utility to remotely access the storage device to determine the amount of water used. Another example of the capability of remotely accessing utility meters involves relatively new electrical utility usage meters. Here, the extent of the use of the electricity, generally in kilowatt hours, is stored in a memory, or similar read/write device. Each such electrical meter has a unique identity so that when interrogated from a remote location, the usage data of a particular meter can be obtained. Further, the telemetry of signals between the electric meter and a remote accounting office is carried out by way of modulation of the AC power line. This technique as the advantage that no additional telephone line is required and thus the transmission medium incurs no additional cost, and the telemetry of utility usage signals does not hamper or interfere with the general distribution of AC power. Moreover, since the utility usage signals are superimposed on the AC line voltage, the utility meters can be remotely accessed at every location where there is a distribution of AC power. Because the electric and water utilities are generally independent entities, the development of the two different types of remote meter reading techniques has developed. As a result, it is believed that without the availability of the present invention, electric utilities would remotely access the electric meters via the AC power lines to obtain readings, while the water utilities would remotely access the water meters utilizing the telephone system. It can be appreciated that in employing either of the above-mentioned techniques, an important consideration is the reliability of the systems to properly register the correct usage of the utility. This problem can be significant in the utility field, where unless otherwise accounted for, erroneous usage indications could be registered in the meter. If an erroneous excessive accumulation is registered during a power outage or lightning strike to the lines, or other intermittent interruptions occur, then the customer is overcharged. On the other hand, if the registration of usage data in the storage memory is insufficient, the utility company is deprived of revenue. It can be seen from the foregoing that a need exists for an improved technique for providing a central meter storage area such that the usage data of each type of utility of a residence or business can be stored in a single storage medium and made available for remote accessing. A more particular need exists for an interface adapted for use with an electric utility meter which enables the input thereto of usage data of other types of utilities. A further need exists for a technique for accessing and remotely reading electrical, water and/or other usage data from a single data base, and transmitting such information over the AC power line. SUMMARY OF THE INVENTION According to an important feature of the invention, there is disclosed a meter interface for receiving utility usage information from one type of utility meter, and transferring an indication thereof for storage in a different type of utility meter or apparatus. Memory storage areas in the utility meter apparatus which are now typically used for other purposes are utilized instead for storing usage data of another type of utility. In accordance with the preferred embodiment of the invention, poorly defined inductive electrical pulses from a water meter defining volume usage are received by the meter interface of the invention and regenerated as other pulses for transferral to a storage medium within a transponder associated with a utility meter. Such embodiment additionally includes a non-volatile storage element for storing an indication of water usage for later transferral to the electric meter transponder, should a power outage render the transponder storage medium unresponsive to regenerated pulses from he interface. The interface of the invention includes first and second timer circuits, responsive to a DC supply voltage from the electric meter transponder for regenerating the water meter pulse and transferring the same to the storage medium of the transponder. According to the particular structure and operation of the preferred embodiment of the invention, a short inductive pulse of about ten milliseconds (ms) is transmitted from the water utility meter to the meter interface to close the pair of contacts of a non-volatile magnetic latching relay. One set of contacts connects a DC supply voltage from the electric meter transponder to the timer circuits of the interface. The other contact connects the transponder input circuits to a solid state switch which is controlled to provide a delayed, regenerated pulse to the transponder for storing indications of the water usage. A first unijunction transistor timer is responsive to the switched DC supply voltage for initiating a delay before transferring a water usage pulse to the transponder input. The first timer comprises a unijunction transistor circuit which, when timed out after a short period, triggers a silicon controlled rectifier (SCR) switch, the conductive state of which pulses the transponder. Also, upon application of the DC supply voltage to the meter interface, a second unijunction transistor timer begins a longer timing cycle, after which a second SCR is triggered to reset the non-volatile magnetic latching relay to open the contacts. The supply voltage is then removed from the meter interface and the interface is placed in condition for receiving another inductive pulse from the water utility meter. When in the inactive state, the meter interface of the invention draws no power from the utility meter transponder. In accordance with an important aspect of the invention, should the electric utility meter and associated transponder be inoperative due to a electric power failure, a water usage pulse is still effective to set the non-volatile magnetic latching relay and store such information until AC power is restored. When power is restored, the DC supply voltage is transferred from the transponder through the closed magnetic latching relay contacts to then initiate the first and second timing cycles. The meter interface then commences operation in the normal manner to transfer a delayed and regenerated water usage pulse to the electric meter transponder storage circuit. BRIEF DESCRIPTION OF THE DRAWINGS Further features and advantages will become apparent from the following and more particular description of the preferred and other embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters generally refer to the same components or circuits throughout the views, and in which: FIG. 1 is a block diagram illustrating an electric utility meter transponder for storing power usage data and load monitoring data, which data are remotely accessible via AC power lines; FIG. 2 is a diagram illustrating the connection of the water utility meter and associated equipment to the electric meter transponder; FIG. 3 illustrates a generalized block diagram of the meter interface of the invention as connected between a water meter and the electric meter transponder; FIG. 4 is a detailed electrical schematic drawing of the meter interface according to the preferred form of the invention;. FIG. 5 is a set of electrical waveforms to facilitate understanding of the circuit of FIG. 4, and FIG. 6 is an alternative embodiment of the meter interface of the invention. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates in basic block diagram form a utility meter transponder 10 with which the invention may be advantageously practiced. Transponders of such type are well known in the art for communicating electric utility meter readings by way of the 120 VAC power distribution system, which includes the hot wire 12 and the corresponding neutral wire 14. Among the well known transponder systems is the Two Way Automatic Communication System (TWACS®) manufactured by Chance Load Management Systems, St. Louis, Missouri. Such a transponder is disclosed in U.S. Pat. Nos. 4,106,007 and 4,400,688. The disclosure of such patents is incorporated herein by reference thereto. Other types of similarly operating systems include the EMETCON Automated Distribution System, obtainable from ABB Power T&D Company, Inc. Raleigh, N.C. For example, the transponder 10 includes a modulator/demodulator 16 which is connected between the AC power wires 12 and 14. For the TWACS system, the modulator/demodulator 16 is effective to modulate a signal corresponding to meter usage data by pulse code modulation (PCM) techniques on the 120 VAC wire. The Emetcon system utilizes a carrier injection communication system on the AC power lines. Other power line communication systems could also be used. The demodulator portion 16 can also receive signals from the AC power wires 12 and 14 transmitted by remote accessing equipment (not shown). Transponder 10 further includes signal processing circuits and memory 18 coupled by a bi-directional bus 20 to the modulator/demodulator 16. The transponder 10 includes a pair of ports, one, 21 is typically used for monitoring the entire electrical requirements, generally in kilowatt hours, used by the residents or business. An auxiliary port 24 of the transponder 10 can be used to optionally monitor usage requirements of individual appliances, such as water heaters, furnaces, etc. The transponder port 21 is utilized by connecting I/0 lines 23 to a connector 22. The auxiliary port 24 is utilized by connecting other I/0 lines 26 to a similar type connector 25. Electric usage from an electric meter, or the like, can be input to transponder port 21, and appropriately processed for writing a memory to store the usage data therein. Electrical pulses input to the auxiliary port 24, generated by pulsing electric meters of yet other appliances, or the like, can be stored in, the memory in like manner. Both types of usage data can be read from the memory by remote access equipment. Typically, transponders 10 of the type described have adequate memory capability to store information in the nature of total kilowatt hour readings, load survey schedules, time of use schedules, demand data, control load data and power outage information. With regard to the control load data information, the transponder 10 can be remotely accessed to control external loads, via load control output 28. Importantly, the section of memory storing total kilowatt hour readings is divided into two areas, one is typically used for storing the whole house usage data input to transponder port 21, and the other area storing single appliance usage data, input to auxiliary port 24. According to an important feature of the invention, the connector 25, associated with the auxiliary port 24, is disconnected from the appliance and is employed to input other usage data, such as water usage or gas usage. With reference now to FIG. 2, there is illustrated the physical arrangement in which a water meter 30 is connected to the transponder 10 for registering water usage data in the memory thereof. It should be understood that while the following example is described in terms of providing remote accessibility to water usage data, any other electrical or nonelectrical utility or nonutility device can be utilized as a device to generate a parameter for storage in the memory of the transponder 10. According to such arrangement, an electric meter 32 includes connector tabs 34 pluggable into corresponding sockets 36 of a transponder housing 38. The transponder 10 itself is connected to the housing 38 by way of a conduit 40 which carries the various signal conductors required for operation thereof. The transponder housing 38 also includes connector tabs 42 pluggable into corresponding sockets 44 of a meter socket 46. As can be appreciated, conventional pulsing electric meters 32 are pluggable directly into the meter socket 46, but with the provision of the transponder 10 for remote access capabilities, the electric meter 32 plugs into the transponder housing 38, which housing is then pluggable into the meter socket 46. Of course, the pulsing output 23 of the electric meter 32 is connected to the connector 22 of the transponder 10. Very little on-site modification of the utility apparatus is required to provide the remote accessing capability. A cable 50 having multiple conductors carries the various signals to and from the transponder 10. The meter interface circuit of the invention, not shown in FIG. 2, is also fastened within the transponder housing 38 and connected to the transponder circuits in a manner described below. The heavy gauge utility lines 52 are brought into the meter socket 46 from either utility pole or underground power distribution systems. The power line 52 is connected to the electric meter 32 by way of the various connectors and sockets. In addition, the transponder 10 is connected between the 120 VAC line 12 and the neutral line 14 as described in connection with FIG. 1. AC power is branched from the meter socket 46 by an AC power bus 54 to a circuit panel breaker, or the like, for further household distribution. Rather than communicating water usage data by way of dedicated telephone lines, the water meter 30 shown in FIG. 2 is branched in parallel to both an odometer 56 to provide visual readings, as well as by conductor 58 to the meter interface circuit of the invention. The water meter conductor 58 is routed through the electric meter socket 46, and through cable 50, to the meter interface of the invention held within the transponder housing 38. The water meter odometer 56 is optional, as water usage data is registered in accordance with the method and apparatus of the invention in the memory circuits of the transponder 10. It is important to understand that conventional pulsing water meters 30, as well as pulsing gas meters (not shown) are equipped with inductive circuits which generate a pulse after a predetermined amount of usage of the particular utility. For example, some water meters produce a pulse to increment the odometer 56 after the usage of 100 gallons of water, while other meters produce such a pulse after the usage of 1000 gallons of water. The same principle is employed in gas meters after a predefined volume (cubic feet) of gas passes through the meter. According to the invention, such pulses are also routed through conductor 58 to the meter interface of the invention. Referring now to FIG. 3, there is illustrated in generalized block diagram form the utility meter interface of the invention. The meter interface, generally designated by reference character 60, is preferably connected between the utility meter 30 and the connector 25 of the auxiliary port 24 of the transponder 10. A pair of conductors 62 from the water meter 30 are connected to a terminal block 64. A terminal block 25 provides an interconnection between the auxiliary port 24 of the transponder 10 and the meter interface 60. The meter interface 60 includes a memory element, comprising a magnetic latching relay, having a pair of normally-open contacts 68 operated to a closed position by a relay set coil 70, and opened by the operation of a reset coil 72. The components of the relay are normally packaged together in a dual in-line package, but need not be. One relay contact 74, when closed, applies a +5 volt supply voltage from the transponder auxiliary port 24 to the meter interface 60. Another relay contact 76, when closed, connects a pulse generator, comprising a first solid state switch 78 and trigger circuit 82, to a pulse input of the auxiliary port 24 of the transponder 10. A circuit common path 80 is connected to the common conductor of the auxiliary input 26. The first solid state switch 78 is triggered by a first timing trigger circuit 82 in response to the application of the supply voltage to the bus 84. In like manner, a second timing trigger circuit 86 is responsive to the same application of the supply voltage to the bus 84 to trigger a second solid state switch 88. When the second solid state switch 88 is triggered, current flows through the delay reset coil 72, thereby opening the contacts 68. Importantly, the delay of the first timing trigger circuit 82 is less than that of the second timing trigger circuit 86. The circuits 86 and 88 can also be considered a pulse generator. In operation, the water meter 30 provides an output inductive pulse across the conductor pair 62 after a predetermined volume of water has passed through the meter. Such a pulse drives a current through the relay set coil 70, thereby closing the latching relay contact 68. Because of the latching feature of the relay, the contacts 68 remain closed, even after the water meter pulse has ceased driving current through the relay set coil 70. When the latching relay contacts 68 are closed, a +5 volt supply voltage is applied to the first and second timing trigger circuits 82 and 86, as well as to the solid state switch 88, via the relay reset coil 72. However, the second solid state switch 88 remains nonconductive, until triggered by the second timing trigger circuit 86. In response to the application of the supply voltage to the bus 84, both trigger circuits 82 and 86 begin their respective timing cycles. The first timing trigger circuit 82 times out first, whereupon the solid state switch 78 is triggered. The solid state switch 78 holds the pulse input of the auxiliary input 26 to a low level. The low level on the auxiliary pulse input signifies to the transponder interface 25 that a unit of utility usage has occurred. In a conventional manner, the transponder processing circuits 18 process such signal for storage in the memory for subsequent accessing from a remote location. Importantly, the water usage data is stored in the transponder memory in the location previously occupied by data indicative of electrical appliance load data. In this regard, the meter interface 60 is completely transparent to the transponder 1. In other words, the transponder 10 processes the signal inputs on its auxiliary port 24 in a manner no different than the signals input as indications of single appliance load data. Subsequent to the time out of the first timing trigger circuit 82, and after the water usage indication has been registered in the transponder memory, the second timing trigger circuit 86 completes a timing cycle. As noted above, the timing cycle of the second trigger circuit 86 is substantially longer than that of the first trigger circuit 82. When timed out, the second trigger circuit 86 triggers the second solid state switch 88, whereupon a current is drawn through the relay reset coil 72. The current through the reset coil 72 is effective to open the latching relay contacts 68 and effectively remove the meter interface 60 from the auxiliary port 24 of the transponder 10. The meter interface 60 is thus preconditioned to receive another pulse from the water meter and repeat the operational cycle. Importantly, when the meter interface 60 is not in an operational cycle, it is completely disconnected from the transponder 10 and requires no power therefrom. In accordance with another important feature of the invention, the meter interface 60 is adapted to store an indication of a nit of utility sage, even if a power outage has occurred and the transponder 10 is not capable of registering therein such usage data. For example, in the event of a power outage, no supply voltage is available from the auxiliary port 24 to the meter interface 60. Notwithstanding, and if water should be used during the power outage, the water meter 30 will yet transmit a pulse through the relay set coil 70, and will close the latching relay contacts 68. However, because no supply voltage is coupled to the interface bus 84 in this situation, the first and second trigger circuits 82 and 86 do not begin their timing cycles. When power is restored to the AC distribution lines, and thus to the transponder 10, the supply voltage will be coupled through the previously closed relay contacts 68 to the interface bus 84. The first and second trigger circuits 82 and 86 will then begin their respective timing cycles, whereupon an operational cycle is completed, as described above. Having described the basic operation of the meter interface 60 of the invention, reference is now made to FIG. 4 where a detailed electrical schematic drawing is shown. The first solid state switch 78 comprises a silicon controlled rectifier (SCR) 90 having its anode connected to a pole 92 associated with the latching relay contact 76. The cathode of the SCR 90 is connected to the meter interface common bus 80. Resistor 95 provides adequate current to the SCR 90. A bypass capacitor 94 is connected across the anode and cathode of the SCR 90 to prevent false triggering of the device due to quick changing voltage transitions. A resistor 96 connected between the gate of the SCR 90 and the circuit common 80 increases the sensitivity of the device. The first timing trigger circuit 82 includes a programmable unijunction transistor (PUT) 98. The gate of the PUT 98 is connected to the junction of two resistors 100 and 102 which comprise a voltage divider between the supply voltage bus 84 and the common bus 80. The value of the resistors 100 and 102 is chosen such that the trigger voltage applied to the gate of the PUT 98 is about two thirds the magnitude of voltage applied to the bus 84. The anode of the PUT 98 is connected to the junction of a resistor 104 and a timing capacitor 106. The value of the resistor 104 and the capacitor 106 is chosen such that as the capacitor 106 charges, the voltage applied to the anode of the PUT 98 equals or slightly exceeds the reference voltage on the gate after a predefined period of time. In the preferred embodiment of the invention, the reference voltage applied to the gate of the PUT 98 is about 2.5-4 volts, and the time constant in which the capacitor 106 charges to the same voltage value is about 100 milliseconds. Such time period applies to the TWACS system, while different time constants may be required for other transponder systems. Accordingly, when a supply voltage is connected to the supply bus 84, the PUT 98 will become conductive a delay period of about 100 milliseconds thereafter. The cathode of the PUT 98 is connected through a resistor 108 to the circuit common 80. The resistor 108 is selected in value so as to limit the current flowing from the PUT 98 to the circuit common 80. Another resistor 110 is connected between the cathode of the PUT 98 and the gate of the SCR 90. Resistor 110 also limits the trigger current supplied by the PUT 98 to the gate of the SCR 90. A filter capacitor 111 is connected between the supply voltage bus 84 and the circuit common 80 to suppress transients, such as those caused by contact bounce, or other transients coupled from the transponder 10 to the meter interface 60 by way of the conductors connected to the terminal block 25. The second timing trigger circuit 86 is similar to the first trigger circuit 82, with the exception of various circuit values which are effective to increase the timing cycle. The second timing circuit 86 includes a programmable unijunction transistor 112 having a gate connected between a resistor divider comprising resistors 114 and 116. The anode of the PUT 112 is connected to the junction of an RC network, comprising a resistor 118 and timing capacitor 120. In the preferred embodiment of the invention, the values of the resistor 118 and the capacitor 120 are chosen such that a timing cycle, or delay, of about 200-300 milliseconds is realized, again for the TWACS system. Connected to the cathode of the PUT 112 is a resistor 122 connected to the circuit common 80, as well as a resistor 124 connected to the gate of an SCR 126. After the second timing trigger circuit 86 completes its timing cycle, the PUT 112 is triggered, thereby generating a current coupled to the gate of the SCR 126, thereby triggering the second solid state switch 88. The second solid state switch 88 includes the SCR 126 with a cathode terminal connected to the circuit common 80, and an anode terminal connected to one end of the latching relay reset coil 72. The other end of the reset coil 72 is connected to the supply voltage bus 84. A diode 128 is connected in a reverse-biased manner across the reset coil 72 to reduce inductive voltage spikes. A capacitor 127 is connected across the anode and cathode of the SCR 126 to reduce false triggering of the device. The relay set coil 70 has a diode 130 bridged across it for similar purposes. In accordance with an important feature of the invention, a silicon diode 131 is connected in series with the relay set coil 70 to provide half-wave rectification of signals carried by the conductor pair 62. Although the series diode 131 does prevent the full water meter pulse voltage from being developed across the set coil 70, the rectification action thereof has been found to be beneficial, in that reverse currents through the coil 70 are prevented. In other words, the signal generated by the water meter 30 frequently has positive and negative polarity excursions due to ringing and transients. While the positive excursions through the set coil 70 are of sufficient duration and magnitude to close the relay contacts 68, the negative excursions can sometimes be of a sufficient magnitude to reverse the current through the coil 70 and cause the contacts to again open. Hence, the series diode 131 allows current to flow through the set coil 70 in only a single direction to prevent inadvertent release of the contacts 68. Having identified and described the functional characteristics of the various components of the meter interface 60, the detailed operation will be described below in conjunction with the waveforms of FIG. 5. The water meter pulse 132 is representative of the signal generated by conventional water or ga meters to trigger odometers and similar devices. Such a pulse 132 is also utilized to set into operation the meter interface 60 so that a regenerated pulse can be registered in the memory circuit of the transponder 10. The water meter pulse 132 is generated by inductive techniques in the water meter, and thus is not a waveform having well defined rising and falling edges, but rather is accompanied by ringing, as noted above. A rectified water meter pulse is shown as numeral 133. Because of the low energy level of the rectified water meter pulse 133, a magnetic latching relay should be selected so that at least the set coil thereof is energized sufficiently such that the contacts 68 close and remain closed. Preferably, a relay should be selected having a set coil characteristic such that the contacts are reliably operated and latched in response to a pulse having a ten millisecond duration and a magnitude higher than about 3.5 volts. In the preferred form of the invention, magnetic latching relays of the type well adapted for use in the invention include the type identified by 327-21E200, obtainable from Midtex Relays, Inc., El Paso, Texas. Of course, other magnetic latching relays may be readily available and suitable for use with the invention. Importantly, the magnetic latching relay employed in the meter interface 60 is of the type having independent set and reset coils. Again, other magnetic latching relays may be suitable for use with the invention, and being of the type having a single coil which is set by a current flowing therethrough in one direction, and reset by a current flowing therethrough in the other direction. In any event, after a prescribed volume of water has passed through the water meter 30, a pulse 132 is generated and applied to the meter interface terminal block 64, via the conductor pairs 62. The rectified pulse 133 drives a current through the relay set coil 70 and through the diode 131, thereby causing the contacts 68 to become latched in a closed position. It is to be noted that the relay contacts 68 illustrated in FIG. 4 are shown in an open position, such as when the meter interface 60 is in a quiescent state. Once the magnetic latching relay contacts 68 are closed, the +5 volt supply voltage is applied from the transponder 10 to the supply voltage bus 84. Such time period is shown as the broken vertical line 134 in FIG. 5. The waveform 136 depicts the voltage across the SCR 90 before, during and after the operational cycle of the meter interface 60. The part of the waveform illustrated as reference number 138 is actually an open circuit voltage, illustrating the voltage across the SCR 90 before the switch contacts 76 have closed. That part of the waveform identified as 140 illustrates the time period in which the SCR 90 connected to the transponder auxiliary terminal block 25 through contact 76 is pulled up to a voltage of about +5 volts. Such a voltage is supplied through a resistance by the transponder 10, through the "input" conductor, but is then pulled low when the SCR 90 is driven into a conductive state. The waveform 142 illustrates the waveform generally across the SCR 126 which comprises the second solid state switch 88. Again, a waveform portions 144a and 144b are open circuit voltages, as during such time no supply voltage is applied to the meter interface 60. Once the supply voltage is applied to the meter interface 60, both the first trigger circuit 82 and the second trigger circuit 86 begin their respective timing cycles, i.e., capacitor 106 begins charging, as does timing capacitor 120. The charging cycle of capacitor 106, associated with the first trigger circuit 82 charges according to the curve 146, while the charging curve of timing capacitor 120 is shown as reference numeral 148. The threshold of the first timing circuit 82, as established by resistors 100 and 102, is shown by the horizontal dotted line 150. The threshold of the second timing circuit 86, as established by resistors 114 and 116, is shown by horizontal dotted line 152. When the charge across timing capacitor 106 is substantially equal to the trigger point 150, the PUT 98 is driven into a conductive state and supplies current to the gate terminal of the SCR 90, comprising the first solid state switch 78. The SCR 90 is then driven into a conductive state to drive the transponder input terminal to a low voltage, as shown by waveform transition 154. The water meter pulse is thus effectively regenerated as a longer duration low level, as noted by numeral 156. As noted above, the transponder 10 is responsive to such an input to thereby register in the memory corresponding usage data for water consumption. The duration of the low voltage level 156 is not critical, but may depend on the type of the transponder utilized. In the TWACS transponder noted above, such duration 156 is about 100-200 milliseconds to insure reliable operation, although it could be less. The initial high voltage portion 140 of the waveform 136 is also about 100 milliseconds, as defined by the value of resistor 104 and capacitor 106. Such time period is selected as a delay period between the water meter pulse input and the regenerated low voltage applied to the transponder auxiliary port 24. The generation of such a time period is important especially during the recovery of a power outage, when the transponder circuits are recovering and initializing to predefined states. The delay shown by waveform portion 140 allows the transponder circuits to "warm up" and be completely responsive after a power outage recovery so that no information will be lost between the meter interface 60 and the transponder 10. Such time period applies to the TWACS system, while different time constants may be required for other transponder systems. The entire timing cycle of the second trigger circuit 86 is selected such that the first trigger switch 78 is operated for a time sufficient for registration of the utility usage in the transponder memory, and thereafter the second timer 86 times out to activate the second solid state switch 88. As noted above, the entire timing cycle of the second trigger switch is set at a nominal 200-300 milliseconds for the TWACS system. The activation of the second solid state switch 88 is noted by transition 158. As can be seen, when the voltage across the timing capacitor 120, shown as broken line 148, reaches the threshold set point voltage 152, within a margin of a semiconductor junction threshold, the PUT 112 is driven into a conductive state. When conductive, the PUT 112 drives the gate terminal of the SCR 126 and it drives it into conduction as well. When driven into a conductive state, the SCR 126 draws supply voltage current through the relay reset coil 72, thereby causing the latching relay contact 68 to open. The interface circuit 60 is then preconditioned to receive further indications of utility usage from the water meter to carry out another operational cycle. While the principles and concepts of the invention can be carried out utilizing different circuit configurations and components, it is believed that the circuit of FIG. 4 has advantageous characteristics. For example, the magnetic latching relay can be latched to hold a state, irrespective of the powered, or unpowered state of the transponder. The latching relay is highly immune to inadvertent operation caused by transients and electromagnetic interference (EMI). This is an important aspect, insofar as circuits in the vicinity of power lines can be subjected to high EMI voltages. The relay contacts additionally provide a high degree of electrical isolation between the transponder 10 and the meter interface 60. With a high degree of isolation, irregular pulses generated by the water meter lines will not be carried through to the transponder 10. Those skilled in the art may find that an optical coupled switch can be substituted for the contact 76. Unlike solid state memory of flip-flop circuits, the relay is immune to false triggering, in that it has a higher threshold voltage and a slower response time. In addition, unlike solid state circuits, the relay is not easily damaged by high speed and high power transients, and indeed the relay may not even be operated when exposed to such transients, as contrast with counterpart semiconductor storage circuits. An important aspect of the use of a latching relay in the meter interface 60 is that it can be operated without an external DC supply voltage. Another technical advantage of the invention is that the solid state devices utilized in the meter interface 60 are of the type which are rugged and highly immune to damage because of electrical transient voltages. The programmable unijunction transistors are also highly reliable and provide a high degree of repeatability of time periods, if the RC components have adequate temperature and life characteristics. The first and second trigger circuits 82 and 86 provide time periods generally independent of internal PUT device characteristics, but rather depend on the external capacitor and resistor characteristics which can be chosen with a high degree of selection and care. When considering the delay or time periods employed with the present invention, the generation of such periods by the trigger circuits are generally insensitive to supply voltage variations. The invention has been described above in terms of the transponder being associated with the electric meter for communication over the AC power transmission line. Such an arrangement is not necessary to carry out the principles and concepts of the invention. Indeed, a transponder can be associated with a water meter and used with the interface of the invention to input thereto gas or electric usage data for transmission over the telephone. Other arrangements are possible. In accordance with yet another embodiment of the invention, there is disclosed in FIG. 6 another meter interface 160. In this embodiment, no transponder warm-up time delay is provided, but rather a regenerated utility usage signal is immediately applied to the transponder 10. The meter interface 160 of FIG. 6 is essentially the same as that of FIG. 4, with the exception of the absence of the first solid state switch 78 and the first timing circuit 82. Rather, the magnetic latching relay contact 76 is switchable to a pole 162 which is connected to the circuit common 80. In operation, when the water meter pulses the relay set coil 70, the contacts 68 latch in a closed condition. Power from the transponder 10 is applied to the second timing circuit 86 which commences its timing interval. The RC components 118 and 120 in this circuit may be chosen to achieve a timing cycle of about 100 milliseconds. After such timing cycle, the SCR 126 is triggered and the relay contacts 68 are opened. The regenerated pulse input to the transponder auxiliary port 24 is still about 100 milliseconds in duration for the TWACS system, but is not preceded by the delay identified by curve portion 140 in FIG. 5. The components of the meter interfaces 60 or 160 can be assembled on a small printed circuit board and encapsulated within a polycarbonate enclosure. The conductors of the interface circuit can extend from the encapsulant through an opening in the polycarbonate enclosure and be connected to the appropriate terminal blocks. From the foregoing, disclosed are methods and apparatus adapted for storing multiple types of utility usage data in another type of utility meter storage area. An advantage of such type of technique is that no modifications need be made to the transponder itself in order to store water, gas or other types of utility usage data in the storage area. When the transponder is accessed from a remote location to retrieve the usage data, the usage data input via the meter interface can be interpreted as such, rather than appliance load data normally stored in such location. When such data is collected from a number of meters, a file in the nature of magnetic tapes or disks can be transferred to the appropriate utility for billing the customers for the utility usage. In this manner, and in the example given above, the water utility companies need not concern themselves with reading the meters or maintenance or the rental of telephone lines, but rather need only process the accounting records to bill the customers appropriately. Those skilled in the art may readily appreciate from the foregoing that the invention and the apparatus described above can be expanded to accommodate additional transponder ports for the simultaneous input of water usage data, gas usage data, etc. In other words, transponders may be devised with a number of ports and corresponding storage areas in the memory so that many different types of usage data can be stored therein and retrieved remotely by way of the AC power lines. Each such transponder port may be equipped with a meter interface of the invention to process the magnetic output of the respective utility meters and to regenerate appropriate input to the transponder for storage in the appropriate memory locations. While the preferred and other embodiments of the invention have been disclosed with reference to specific meter interfaces and methods, it is to be understood that changes in detail may be made as a matter of engineering choices without departing from the spirit and scope of the invention, as defined by the appended claims.
An interface to facilitate storing in an electric utility meter transponder, water usage data so that when remotely interrogated, access can be had to both electric and water usage data. A pulse indicative of water usage sets a magnetic latching relay in the interface circuit which causes a transponder supply voltage to be switched to two interface circuit timers. The first timer generates a first delay, after which the electric meter transponder is pulsed to register water usage. After a second, longer delay, the second timer resets the magnetic latching relay to thereby place the interface circuit in condition for receiving another water usage signal.
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This patent application is directly related to U.S. provisional patent application No. 60/146,672, filed Aug. 2, 1999, the entire contents of which are hereby incorporated by reference and relied upon. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is for an apparatus and a method for anticipating disk burst failures in turbo-machinery blades. The apparatus comprises at least one blade tip sensor for sensing blade passage making measurements of blade tip time-of-arrival and clearance from the sensor to a blade tip and a computer for compilation and analysis of data from the sensor. 2. Description of the Related Art If they are not replaced, turbo-machinery disks (spinning hubs and blades) eventually burst due to spin-induced inertial forces and fatigue. The failure pattern varies but is always marked by growth in the diameter of the disk during disintegration. Moreover, such growth is not uniform, but rather biased due to asymmetric crack propagation in the disk. Historic methods to predict disk failure rely on standard materials analysis, including x-ray crystallography, sonograms, and other diagnostic techniques, after the turbo-machinery is disassembled. The predictive value relies on estimating when micro-cracks have formed and then searching for confirmation. Due to wide variations in operating conditions and in the fatigue life of turbo-machinery components, historic-methods require frequent inspection intervals-to maintain safe operation. A recent experimental technique employed in spin pit analyses relies on changes in the imbalance when a suspended turbo-disk is spun on a quill shaft. The reasoning behind this technique is that crack propagation will progressively shift the imbalance in the rotating disk. This technique may have applications in controlled experiments in spin pits, but may be-difficult to apply in engine operation, where many effects cause shifts in imbalance. Disk diameter can be monitored at the blade tips at the outside edge of the disk. For example, in a turbine with N blades, a blade clearance sensing system provides N measures of rotor radius for every engine revolution. The trend of such measurements over many operational cycles can reveal a local bulge or bulges indicative of impending disk burst. The diameter expands elastically as the disk is spun to high rpm and contracts again when the disk is slowed. Such “elastic stretch” can create a relatively large signal, roughly equal for each blade on the spinning disk. The detection system must discount this form of stretch. One way to do so is to compare disk diameter during each operating cycle at the same rpm, so as to detect only variations due to causes other than elastic stretch. An additional complication is the variation due to temperature, which can also add significant increases to the diameter. This too can be disregarded by comparing diameter at constant temperature or by comparing each blade to the average of all blades. It is an object of the present application to present an apparatus and method for anticipating disk burst failures in turbo-machinery which uses one or more case-mounted sensors observing blade passage and interpreting these measurements by searching for unusual deformation of one or a few of the blades. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the phenomenon on which the present apparatus is based: the asymmetric deformation of a turbo-machinery disk due to crack propagation at the base of a set of blades. FIG. 2 illustrates changes in blade length as a turbo-disk is cycled in an experimental spin pit to expose it to low-cycle fatigue. FIG. 3 provides an illustration of the cycles which turbo-machinery experiences in practice: engine speed during flight operations. FIG. 4 is a general illustration of sensor response and of data reduction to identify blade elongation. FIG. 5 shows the apparatus of the present invention for predicting disk failure. SUMMARY OF THE INVENTION The present invention is for an apparatus and a method for anticipating disk burst failures in turbo-machinery blades. The apparatus comprises at least one blade tip sensor for sensing blade passage making measurements of blade tip time-of-arrival and clearance from the sensor to a blade tip and a computer for compilation and analysis of data from the sensor. In preferred embodiments of the apparatus, the analysis compensates for variation due to inertial and temperature effects by comparing each blade to an average of all blades. It also corrects for once-per-revolution, sinusoidal variation by subtracting a best-fit sinusoidal curve. In preferred embodiments of the apparatus, the tip clearance sensor is case mounted. The method for anticipating disk burst failures in turbo-machinery blades, comprises the steps of sensing blade passage and-making measurements of blade tip time-of-arrival and distance from a tip clearance sensor to each blade and analyzing the measurements in a computer. In preferred embodiments of the method, the analyzing step compensates for variation due to inertial and temperature effects by comparing each blade to an average of all blades. It compensates for once-per-revolution, sinusoidal variation of blade position by subtracting a best-fit sinusoidal curve; and for temperature and inertial effects searching for asymmetric patterns of blade deformation. In preferred embodiments of the method, the tip clearance sensor is case mounted. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates the phenomenon on which the present apparatus is based: the asymmetric deformation of a turbo-machinery disk due to crack propagation at the base of a set of blades. Changes in the pattern of blade position are indicative of an impending disk burst. Components of the apparatus of the present invention include one or more sensors to detect disk diameter, a sensor creating a one-per-revolution signal to track angular orientation of the disk, and a temperature sensor. (The one-per-revolution sensor and the temperature sensor are optional.) A computational algorithm is used to reduce the data in order to search for asymmetric patterns in disk deformation. Blade deformation due to inertia, temperature, and once-per-rev sinusoidal variations are disregarded in order to focus the search for blade deformation due to crack propagation. Results of the sensing and algorithmic system are reported in the form of warning signals, other information for human interpretation, and/or data for both real-time and historic computational analysis. Although the apparatus can be designed to monitor and to correct for increases due to temperature and rpm, it can also simply compare each blade to the average of all blades. This latter technique focuses the search on unusual patterns of blade deformation compared to an average, while uniform disk deformation due to temperature and inertial factors can be ignored. FIG. 2 illustrates changes in blade length as a turbo-disk is cycled in an experimental spin pit to expose it to low-cycle fatigue. Actual operating conditions for turbo-machinery typically differ from those encountered in experimental circumstances. Blade lengths vary with rpm and with temperature. It is possible to correct for these variations. Blade length changes can also be compared to the average length change of all blades in that stage, ignoring temperature and rpm effects. Plastic deformation is identified by an irreversible blade deformation. FIG. 3 provides an illustration of the cycles which turbo-machinery experiences in practice: engine speed during flight operations. A jet aircraft engine in normal commercial service undergoes relatively few variations in rpm during each flight. An out-of-round disk pattern may occur for reasons that do not lead to disk burst. Examples include imbalance shift, bearing wear and spool bow. Such factors create once-per-rev sinusoidal variations in the measurements. The algorithm governing this apparatus removes such phenomena from the prediction of burst failure. For each engine revolution, a set of measurements of blade tip clearance is created. The algorithm is designed to develop a “best-fit” one-per-rev sinusoid arid to subtract it from the measurement data. The remaining changes in tip clearance are therefore due to blade deformation, which in turn can indicate incipient disk burst. Instrumentation and its governing algorithm provide a real-time display of the data, in the format illustrated in FIG. 4, i.e., a general illustration of sensor response and of data reduction to identify blade deformation. The graphs illustrate the measurements of blade deformation captured by sensors and the general principles used to reduce measurement data in order to identify asymmetric plastic deformation. Imbalance can be caused by rotor bow and other effects not indicative of disk burst. When such factors are subtracted from the data, the remaining long-term trend of the data then indicates higher-order measures of disk out-of-round. Growth of a neighborhood of blades can indicate incipient disk burst. FIG. 5 shows the apparatus of the present invention for predicting disk failure. Sensors provide adequate stand-off distance for temperature and inertial growth and for asymmetric deformation due to once-per-rev sinusoidal variations and to crack propagation. The system requires at least one tip clearance sensor, but additional sensors provide redundancy and permit more data analysis. Computational algorithms provide warning signals and displays and data for further interpretation. The resolution in tip clearance measurement should be about 0.001 inch (0.025 mm), obtained at an adequate “stand-off” distance. Inertial (rpm-induced) elastic growth of the blades may be as large as 0.150 inch (4 mm), and thermal expansion may account for as much as 0.040 inch (1 mm) for large disks. Sensor stand-off distance must thus be about 0.2 inch (5 mm), maybe more if disk run-out is significant. Capacitance sensors are capable of operating with such clearances and at the necessary resolution, though other sensors may also be used. The sensing and data reduction system can operate with one sensor, or with multiple sensors simultaneously. The features of the present apparatus to predict disk failure in turbo-machinery are: (1) A means of tip-sensing blade deformation as a predictor of incipient crack growth leading to disk burst. The apparatus described above relies on a novel means of detecting crack creation and growth in turbo-machinery. Unlike traditional techniques, it does not require disassembly of the engine, but rather is designed to operate under engine operating conditions while the disk is in motion. Unlike a laboratory technique, it is intended to perform while in turbo-machinery under operating conditions and to provide real-time prediction of disk health or failure. It employs a novel conception of how crack growth contributes to asymmetric growth of the disk and of how to detect and analyze that growth. (2) An algorithm to reduce measurement data in order to isolate growth in blade deformation due to crack development. The algorithmic analysis of data relies on a novel combination of straightforward techniques to reduce the sensor measurements to detect crack growth. The algorithms developed for this apparatus adjust for variations in rpm and its inertial effect on disk deformation. They also cancel out temperature effects on blade growth. And finally, they use a “best-fit” once-per-rev sinusoid to account for such effects as imbalance shift, bearing wear and spool bow. Elimination of such inertial, temperature, and sinusoidal effects provides the opportunity to focus on the results of micro-cracks. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but on the contrary is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Thus it is to be understood that variations in the present invention can be made without departing from the novel aspects of this invention as defined in the claims. All patents and articles cited herein are hereby incorporated by reference in their entirety and relied upon.
An apparatus is described for detecting the early signs of cycle-induced fatigue and thereby predicting failure of the rotating disk in turbo-machinery. It identifies asymmetrical growth of hub-blade diameter as a predictor of incipient crack growth. Tip measurements are processed through specialized algorithms to detect such asymmetry during operation, providing a real-time, non-destructive method of prediction. The sensors can be housed within the machinery case, and are capable of operating in harsh environments while maintaining adequate stand-off distance, making the entire apparatus robust enough for conditions in high-speed turbo-machinery.
8
TECHNICAL FIELD The present invention relates to clamps that allow vibratory devices to be attached to elongate members and, more particularly, such clamps that are adapted to connect a vibratory device to a caisson to allow the caisson to be driven into the earth. BACKGROUND OF THE INVENTION In the construction industry, it is often necessary to insert pipe-like bodies into the earth. Such pipe like bodies are referred to as caissons in most situations and often as casings in the context of a pipe that is inserted into the earth during drilling operations. As examples, caissons are inserted into the earth during new construction as part of a foundation for a structure; caissons are also commonly driven under a bridge or the like when providing additional structural resistance to earthquake damage. Casings are employed when drilling a hole to prevent the earth from collapsing into the hole as it is drilled. In this application, the term "caisson" will be used to refer to any pipe like body that is driven into the earth, including the casings used in drilling operations. To insert a caisson into the earth, a large driving force must be applied thereto. Often, vibratory devices are employed to introduce a vibratory force along the axis of the caisson during the driving process. The combination of a static driving force with a dynamic vibratory force is usually sufficient to overcome the earth's resistance and allow the caisson to be inserted therein. A clamping assembly must be provided to allow vibratory forces to be effectively transmitted to the caisson. Such clamping assemblies have heretofore normally been adapted to engage the upper end of the caisson. But as described in copending patent application Ser. No. 08/408,023 filed by the present inventor, now the U.S. Pat. No. 5,544,979, clamp assemblies also exist that grip the side of the caisson as it is being driven into the earth. The present invention relates to clamp assemblies that engage the upper end of the caisson. Normally, such clamp assemblies comprise a cast beam having individual clamps movably mounted on each end thereof. A vibratory device is bolted to an upper surface of the beam. The beam is then arranged above the caisson upper end and lowered such that opposing portions of the caisson upper end are received between gripping members of the clamps. The clamps are then actuated such that the gripping members grip the caisson upper end and thus fix the caisson relative to the vibratory device. The vibratory device is then operated to create a vibratory force that, in combination with the weight of the vibratory device, clamping assembly, and caisson, drives the caisson into the earth. This arrangement usually works well with caissons of relatively small diameter. With larger caisson diameters, however, the vibratory forces often cause walls of the caisson to vibrate, or diaphragm, especially under hard soil conditions. This diaphragming of the caisson absorbs the vibratory driving forces, preventing the caisson from being driven into the earth and oftentimes resulting in damage to the caisson. At a minimum, diaphragming requires that the driving process be performed more slowly. An undesirable side effect of diaphragming of the caisson is that the vibratory forces are transmitted laterally by the caisson walls into the adjacent soil instead of vertically through the caisson to the lower end thereof. In many situations, such as when the caisson is being inserted adjacent to a building or other structure, these laterally transmitted vibratory forces are highly undesirable because they might unduly stress the adjacent structure. The most common method of overcoming the problem of diaphragming is simply to increase the wall thickness of the caisson. The thicker caisson wall results in a more rigid caisson that resists diaphragming and can therefore be more easily driven into the earth. Caissons with thicker walls are significantly more expensive, however, and the need exists for apparatus and methods for driving caisson assemblies into the earth that allow the use of thin walled caissons under more circumstances. OBJECTS OF THE INVENTION From the foregoing, it should be clear that one primary object of the present invention is to provide an improved clamp assembly for securely attaching a vibratory device or the like to a caisson. A further object of the invention is to provide a caisson clamp assembly having a favorable combination of the following characteristics: (a) allows the use of lighter, thin walled caissons; (b) allows the use of a smaller crane; (c) allows piles to be driven more quickly; (d) ensures that piles stay plumb as they are driven; (e) reduces or eliminates lateral vibrations that are transmitted to the soil and thus possibly to adjacent structures; (f) transfers forces to the caisson in balanced, stable manner; (g) allows caissons to be driven deeper; (h) can be adapted to grip a caisson at either two points or at four points; and (i) is inexpensive to manufacture and use. As will become clear from the following detailed discussion, these and other objects are achieved by the caisson clamping assembly of the present invention. SUMMARY OF THE INVENTION The present invention comprises a clamp assembly for caissons having a first rigid member, a second rigid member, a third rigid member, and first through fourth clamps. Two of the clamps are attached to the first rigid member, while the remaining clamps are attached one each to the second and third rigid members. The rigid members may be in the form of cast I-beams having an upper flange. The upper flanges of the rigid members are attached to a vibratory device such that the second and third rigid members are parallel to a longitudinal axis of the vibratory device and the first rigid member is perpendicular to this longitudinal axis. The clamps are attached to a caisson to be driven into the ground. The clamp assembly provides clamps at four points spaced at equal intervals around the circumference of the caisson. By providing four equally spaced points of attachment around the upper edge of the caisson, vibratory loads imparted to the caisson through the clamp assembly are evenly distributed in a manner that alleviates or prevents diaphragming of the caisson as it is being driven. Without the diaphragming, the vibratory forces are less likely to vibrate the soil. The even distribution of loads also helps to keep the caisson plum as it is driven. The clamp assembly of the present invention also allows the use of a smaller crane and speeds up driving times. By eliminating or substantially reducing diaphragming, the clamping assembly of the present invention also greatly reduces the magnitude of lateral forces transmitted to the soil. Caissons may be driven with the present clamping assembly in locations, such as adjacent to preexisting structures, where they could not have been driven using prior art devices. Additionally, the use of three separate rigid members both: (a) reduces manufacturing costs; and (b) increases the flexibility of the clamping assembly during use. Manufacturing costs are reduced because each of the rigid members is a simple I-beam that may be easily cast using conventional techniques. Flexibility during use is increased because the first rigid member may, when appropriate, be arranged parallel to the longitudinal axis of the vibratory device and used in a conventional manner with two points of attachment. Then, when circumstances dictate, it may be arranged perpendicular to this longitudinal axis and used with the first and second rigid members with four points of attachment. Successive caissons may be driven using the same equipment even though they are of much different diameters and/or are driven under different soil conditions. To provide a stable and secure connection between the clamp assembly and the vibratory device, the upper flange of the first rigid member may be thickened at its central portion relative to the ends of the upper flange and/or the upper flanges of the second and third rigid members. Constructed in this manner, the clamp assembly of the present invention provides a secure four-point attachment system that reduces diaphragming in a flexible manner and at low cost. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view depicting a clamping assembly of the present invention being used in a first mode of use; FIG. 2 is a top plan view of beam members of the clamping assembly shown in FIG. 1; FIG. 3 is a front plan view of the beam members shown in FIG. 2; FIG. 4 is a side plan view of the beam members shown in FIG. 2; FIG. 5 is a somewhat schematic view showing the relationship between the clamping assembly shown in FIG. 1 and the caisson being driven therewith; FIG. 6 is a perspective view depicting a clamping assembly of the present invention being used in a second mode of use; and FIG. 7 is a somewhat schematic view showing the relationship between the clamping assembly shown in FIG. 6 and the caisson being driven therewith. DETAILED DESCRIPTION Referring now to the drawing, depicted at 20 in FIG. 1 is a driving device employing a clamping assembly 22 constructed in accordance with, and embodying, the principles of the present invention. The clamping assembly 22 secures a vibratory device 24 to a caisson 26. The vibratory device 24 itself is connected to a suppresser unit 28. In operation, the suppresser unit 28 is connected to a cable suspended by a crane in a manner that is well known in the art. The vibratory device 24 generates vertical vibratory loads that are imparted to the caisson 26 through the clamping assembly 22 along a vibratory axis A as shown in FIG. 1. A static driving force is also applied by the weight of the entire driving device 20. The suppresser unit 28 substantially isolates the cable and crane from the vertical vibratory forces generated by the vibratory device 24. Of the foregoing components, the vibratory device 24, caisson 26, and suppresser unit 28 are all known in the art and will not be described in detail herein. The exemplary vibratory device 24 and suppresser 28 shown and described herein are available from the assignee of the present application under the trademark KING KONG. Referring now to FIGS. 1-5, it can be seen that the clamping assembly 22 comprises first, second, and third beam members 30, 32, and 34 and first through fourth clamps 36, 38, 40, and 42. In the following discussion, the following axes are illustrated in FIG. 1 to clarify certain features of the present invention. The vibratory axis A, which is normally vertical, coincides with the longitudinal axis of the caisson 26. The vibratory device is generally elongate in overall configuration and has a lengthwise axis B that is orthogonal to the vibratory axis. The beam members 30-34 are also elongate, with the first beam member having a first beam axis C, the second beam member having a second beam axis D, and the third beam member having a third beam axis E. The beam members 30-34 are I-beams, each having upper and lower flanges. A first upper flange 44 and first lower flange 46 are formed on the first beam member 30. Similarly, a second upper flange 48 and second lower flange 50 are formed on the second beam member 32, while a third upper flange 52 and third lower flange 54 are formed on the third beam member 34. The upper flanges 44, 48, and 52 have holes 56 formed therein to allow the beam members 30-34 to be connected to the vibratory device 24 by bolts or the like as will be described in further detail below. As perhaps best shown in FIG. 1, the clamps 36-42 engage the lower flanges 46, 50, and 54 such that these clamps 36-42 can slide along the beam axes C, D, and E but do not move relative to the beams 30-34 along the vibratory axis A. As shown in FIG. 6, the first and second clamps 36 and 38 are attached to the first beam member 30, the third clamp 40 is attached to the second beam member 32, and the fourth clamp 42 is attached to the third beam member 34. The clamps 36-42 are identical and well known in the art and will be described herein only briefly to illustrate the operation of the present invention. Basically, referring to the first clamp 36, it can be seen that this clamp 36 comprises a first hydraulic cylinder 58 for securing the clamp 36 relative to the beam 30 and a second hydraulic cylinder 60 securing the clamp 36 to the caisson 26. Referring again now to FIG. 5, one important feature of the present invention is the use and arrangement of the beam members 30-34 relative to the caisson 26 and vibratory device 24. Referring initially to the relationship between the beam members 30-34 and the vibratory device 24, it can be seen in FIG. 1 that the lengthwise axis C of the first beam member 30 is substantially orthogonal to the lengthwise axis B of the vibratory device. The lengthwise axes D and E of the second and third members 32 and 34 are substantially parallel to the lengthwise axis B of the vibratory device 24. As shown in FIG. 5, this results in the beams 30-34 being arranged in a substantially cruciform shape during use. FIG. 5 also shows that this cruciform shape results in the clamp assembly 22 engaging the caisson 26 at four different gripping locations 62, 64, 66, and 68. Additionally, with the exemplary clamping assembly 22, these clamping locations 62-68 are all spaced at substantially equal 90° intervals from each other. This even spacing of the clamping locations 62-68 results in a more even distribution of vibratory loads being applied to the caisson 26, which dampens the diaphragming that tends to occur without such even spacing. Another feature of the present invention is that the clamping assembly 22 is formed from three separate beam members 30-34. Each of these beam members is a cast I-beam that is relatively easy to fabricate. These separate beam members 30-34 are also relatively easy to store and handle when not in use or during assembly for use. FIGS. 2, 3, and 6 also show that the first beam member 30 is slightly more than twice as long as the second and third beam members 32 and 34. Additionally, the first upper flange 44 of the first beam member 30 is not of uniform size. In particular, as shown in FIG. 2, a width W1 of the first upper flange 44 at a central location 70 is almost twice that of a width W2 of the first upper flange 44 at end locations 72 and 74. The widths W1 and W2 are measured in a direction orthogonal the first longitudinal axis C of the first beam member 30 and to the driving axis A. The thickened central portion 70 provides a larger surface area for attachment to the vibratory device 24 that allows more bolts to be employed to attach the first beam member 30 to a base plate 76 of the vibratory device 24. This thickened central portion 70 also rigidifies the first beam member 30 to accommodate the additional loads that must be transferred in the smaller contact area resulting from the fact that the first beam member 30 is transverse to the vibratory device 24. In the exemplary clamping device 22, the width W1 of the central location is at least 25% of the length of the vibratory device along the lengthwise axis B thereof. The width W2 is at most 20% of the length of the vibratory device along the lengthwise axis B. This arrangement provides a stable, rigid, and balanced configuration to the clamping device 20. As shown in FIG. 3, a plurality of brace members 78 and 80 are formed as part of the first beam member 30 to provide additional support for the first upper flange 44. The brace members 78 are larger than the brace members 80 to accommodate the thickened central portion 70 of the first upper flange 44. The clamping assembly 22 described above is used in the following manner. Initially, the vibratory device 24 and suppresser 28 are obtained as a unit or assembled together so that the suppresser 28 is rigidly connected to an upper plate 82 of the vibratory device. The first beam member 30 is bolted to the base plate 76 of the vibratory device 24 such that its lengthwise axis C is orthogonal to the lengthwise axis B of the vibratory device 24. The second and third beam members 32 and 34 are next bolted to the base plate 76 such that they are on opposite sides of the first beam member 30 and their longitudinal axes D and E are substantially parallel to the vibratory device lengthwise axis B. The entire assembly 20 is then suspended above the caisson 26. At this point or earlier if the diameter of the caisson 26 is known, the clamps 36-42 are arranged on their respective beam members such that they are symmetrically arranged around the vibratory axis A and spaced from each other a distance necessary to accommodate the diameter of the caisson 26. The entire driving device 20 is then lowered to a position where the clamps 36-42 straddle the engaging portions 62-68 of the caisson 26. The second hydraulic cylinder 60 are then operated to lock the clamps 36-42 relative to the caisson 26. The first hydraulic cylinders 58 are then actuated to lock the clamp members 36-42 relative to the first through third beam members 30-34. The vibratory device 24 is now rigidly connected to the four gripping portions 62-68 through the clamping assembly 22. The vibratory device may then be actuated to apply a vibratory load to the caisson 26 for the purpose of driving or pulling the caisson 26. In addition to the first mode of operation shown above with respect to FIGS. 1-6, the clamping assembly 22 has the additional flexibility to be used in a traditional manner with two points of contact. In particular, FIG. 7 shows the clamping device 20 with a clamping assembly 22a thereof arranged in a second mode of operation. As shown in FIGS. 7 and 8, in this second mode of operation the first beam member 30 may be used without the second and third beam members 32 and 34. In this second mode, the longitudinal axis C of the first beam member 30 is arranged substantially parallel to the longitudinal axis B of the vibratory device 24. The clamping assembly 22a of this second mode of use operates in the same basic manner as that of the clamping assembly 22 described above except that, as shown in FIG. 8, the assembly 22a grips the caisson 26b in two gripping locations 84 and 86 that are spaced 180° from each other. The same equipment may thus be used in either of two ways depending upon the situation. In some situations, caissons may be driven in succession using the clamping assembly either in its first mode 22 or in its second mode 22a. From the foregoing, it should be clear to one of ordinary skill in the art that the present invention may be embodied in forms other than those described above in detail. For example, while the exemplary clamping assembly 22 described above preferably contacts caisson at four gripping locations, at least some advantages of the present invention may be obtained by using a clamping assembly that contacts the caisson at three evenly spaced locations. While not yielding many of the benefits of the clamping assembly 22 described above, applying the vibratory forces at more than two (i.e., three or more) evenly spaced gripping locations will result in a balanced configuration that will reduced diaphragming. The above described embodiment is therefore to be considered in all respects illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description. All changes that come within the meaning and scope of the claims are intended to be embraced therein.
An apparatus for attaching a caisson to a device for inserting and/or extracting the caisson. The apparatus comprises three beams. A first beam is relatively long and is normally connected to a vibratory device such that its longitudinal axis is orthogonal to the lengthwise axis of the vibratory device. The second and third beams are relatively short and are connected to the vibratory device such their longitudinal axes are parallel to the lengthwise axis of the vibratory device. Four clamps are mounted on the beams to fix the beams onto the caisson. A flange on the first beam is widened at least a middle portion thereof to stiffen the beam and allow the beam to be securely connected to the vibratory device. The first beam may also be used with its longitudinal axis parallel to the lengthwise axis of the vibratory device.
4
FIELD OF THE INVENTION The invention relates to a reading arrangement for a fast-running dobby having a reading needle of a mechanical reading device engaging the nonperforated or perforated portions of a pattern card. BACKGROUND OF THE INVENTION To control dobbies, pattern cards with nonperforated or perforated portions are used which are read by needles of a control mechanism. The movement of the reading needle toward the pattern card is done with the aid of gravity or in fast-running machines with pretensioned springs or special drive parts. Upon increasing the operating speed, the time which is available for reading is reduced. The reading needles are moved forwardly faster and hit with greater speed the nonperforated parts, and in time can result in fatique distortions in the pattern card, for example deformations and breakage of the nonperforated parts and eventually cause control errors. By reinforcing the pattern card, a stiffening thereof would result and would make same heavier and bulky. The needle mass can be reduced only in as much as the durability of the needle is not affected. A direct and purposeful control of the movement of the needle leads to time losses during the course of the control operation and also causes vibrations in the needle. The purpose of the invention is a simple structure of a reading device for a dobby which permits an increase in the operating speed thereof. This is inventively achieved in a reading arrangement of the abovementioned type by providing an element which yields in axial direction of the reading needle and is arranged either on the reading needle or on the pattern card. With this arrangement, the nonresilient mass portion of the reading needle which directly engages the card can be reduced by reducing the respective needle length to the movement requirements into the pattern card. The needle portion which is necessary for transmitting the reading result is movably connected in axial direction to a base part. The yielding effect can be assured by an elastic deformation or by relative movement against a frictional resistance and the latter can be applied as an additional arrangement parallel to the first one. It is important that the entire needle length is reduced when the needle strikes a nonperforated portion of the pattern card and that prior to the next following reading of the pattern card and during an indexing of the pattern card the original length is again achieved. BRIEF DESCRIPTION OF THE DRAWINGS Exemplary embodiments of the subject matter of the invention are illustrated in the drawings, in which: FIG. 1 illustrates a reading arrangement having a reading needle with a built-in helical spring during a reading of a nonperforated portion of a pattern card; FIG. 2 illustrates a modified embodiment of the inventive arrangement; FIG. 3 illustrates a two-part reading needle, the parts of which are connected by an elastic flexible element; FIG. 4 illustrates a two-part reading needle, the parts of which can be moved toward one another against a frictional force; FIG. 5 is a perspective view of an auxiliary part of the connection in FIG. 4; FIG. 6 is a partly cut view of a modified embodiment of a two-part reading needle; FIG. 7 is a cross-sectional view taken along the line E--E of FIG. 6; FIG. 8 is a schematic view of the principal structure of a reading-in mechanism of a dobby for controlling a weaving machine, as is discussed more in detail for example in U.S. Pat. No. 2,705,505 wherein an inventive spring element is built into the reading needle. This patent is assigned to the same assignee as is the present invention. DETAILED DESCRIPTION FIG. 8 illustrates a pattern card 1 which is moved by a cylinder 10. The pattern card has nonperforated and perforated portions for controlling a dobby of a Hattersley system. The two draw hooks which are associated with a frame of the weaving machine are identified by the reference numeral 12, which draw hooks are pulled out in a patterned manner by the draw knives 13. The schematically illustrated draw bar 14 provides the connection to the frame of the weaving machine. Only the reading-in mechanism which is associated with the lower draw hook 12 will be described hereinafter. The reading needle 5 is loosely suspended by means of an eyelet on an auxiliary needle 2 which lies both in the radiused path of movement of a vertically movable rod 4 and the back and forth movement of a push bar 15. The support needle 16 is slidably supported in an eyelet of the auxiliary needle 2 and the lower end thereof rests on a vertically movable step bar 17. The rod 4 is driven by a two-arm lever 18 which is controlled at one end by a rotatably supported cam member 19. The push bar 15 is driven in the same manner by a rotatably supported cam member 19. The reading needle illustrated in FIG. 1 consists of an upper needle part 50 would around the auxiliary needle 2 and a lower needle part 5 which for reading the pattern card 1 directly cooperates therewith. The auxiliary needle 2 and needle 5,50 are lifted vertically together by the rod 4 prior to an indexing of the pattern card 1. The two parts 5 or 50 of the reading needle are guided in the guideways 3 or 30 affixed to not illustrated support structure. The connection between the lower part 5 of the needle and the upper part 50 consists of a helical spring 55 which is wound out of the material of the reading needle. If the reading needle 5,50--as is shown in FIG. 1--strikes a nonperforated portion of the pattern card 1, the impact of the lower needle part 5 onto the pattern card is absorbed by the helical spring portion 55. If the reading needle 5,50 is received in a perforation, the spring 55 does not influence the needle parts 5,50. A spiral spring or a resilient bar 57 can be utilized instead of the helical spring. In the previously described embodiment, the reading needle does not have a damper and, as a result, vibrations can occur. FIG. 2 illustrates a reading needle having a damping mechanism. The reference numeral 6 identifies the lower part of the needle and the reference numeral 60 identifies the upper part of the reading needle. Both parts are connected together by a press fit type connection to the opposite ends of a helical spring 65. A cage 66 is secured to the upper part 60 of the needle and houses the spring 65 therein and is under a small amount of initial stress while the lower part 6 of the reading needle is axially movably guided in the lower part of the cage. The lower part 6 of the needle is slidably received in the guideway 3. The guideway of the upper part 60 corresponds to the structure of FIG. 1 and is not shown in FIG. 2. A pair of flaps 67 are mounted on the lower part of the cage 66, which flaps grip around the lower part 6 of the reading needle with a small amount of applied pressure. These flaps 67 frictionally dampen any vibrations in the reading needle during contact thereof with a nonperforated part of the pattern card. The cage 66 with the flaps 67 may be made of plastic. Installation of the spring 65 into the cage substantially permits a free selection of the dimension of the spring. According to FIG. 3, the helical spring can be replaced by at least one elastic or flexible block 75 in which is received and secured the separated upper parts 70 and lower parts 7 of the reading needle. The block material functions as the spring and the spring function can still be reinforced by the fastening points 77 for the reading needle parts being provided side-by-side due to an overlapping of the two parts 7,70 and not in an axial direction one below the other. As a result, resilience occurs not only through a compression of the material of the block 75 but also through a shearing effect in the block material. By selectively choosing the material and the dimension of the elastic block 75, the spring characteristics thereof can be varied. The illustrated bent offset 7A in the lower needle part 7 results in the space 78 between the part 7 and the lower end of the upper needle part 70 and serves as a limitation for the reciprocal motion of the spring. In the two further modified embodiments, the yielding element consists of an arrangement in which the reading needle is composed of two parts which move reciprocally in axial direction under friction action. In FIGS. 4 and 5, the lower part of the reading needle is identified by the reference numeral 8 and the upper, independent part of the reading needle by the reference numeral 80. The lower part 8 slides in the guideway 3 and is positioned on a nonperforated portion of the pattern card 1; the upper part 80 slides in the guideway 30 and cooperates with the auxiliary needle 2 which has the part 80 wound therearound. A clip 85 is used as the resilient element in the embodiment of FIGS. 4 and 5 and consists of spring band which is bent to a not quite closed rectangle wherein the free end 86 acts as a resilient pressure element. An opening 87 is provided in each of the upper and lower wall portions of the clip and are adapted to receive and guide the two needle parts 8,80 therein. The ends of the two needle parts 8,80 are bent and engage the outer wall portions of the upper and lower sides of the clip. Reinforced by the force of the resilient part 86, the surfaces of the needle parts frictionally engage one another within the clip 85. The reading needle is held in the illustrated position by this friction force. During a lowering of the reading needle onto a nonperforated portion of the pattern card 1, the impact forces effect a shifting, starting at a fixed threshold frictional value of the lower needle part 8 with respect to the upper needle part 80 and causes the peak of these impact forces to be absorbed. The maximum sliding path 88 is determined by the position of a ring or collar 89 which is pressed onto the lower needle part 8. To index the pattern card, the rod 4 lifts along its path of movement toward the auxiliary needle 2 and carries therewith the entire reading needle 8,80 by engaging the bent end portion of the upper part 80 of the needle until the bent end portion of the upper end of the lower part 8 of the reading needle engages the guideway 30. A continued movement of the rod 4 will cause the lower needle part 8 to be pushed back to the original position thereof relative to the upper needle part 80 and the clip 85. In the modified embodiment according to FIGS. 6 and 7, the mutually adjacent ends of the needle parts 9,90 which are directed toward one another are slidably guided in an opening 97 in a block 95 and are bent backwardly generally 180° until they lie in the lateral groove 96 in the block 95 to cause the arrangement to be secured against rotation. The bent end of the upper part 90 grips around both the upper and lower ends of the block 95 so that a reciprocal relative shifting does not take place. The bent end of the lower part 9, however, can slide slightly in axial direction of the block. When the reading needle hits a nonperforated portion of the pattern card, the lower part 9 thereof is pushed back into the block 95 at a certain relationship with respect to the impact force. During a subsequent lifting of the upper part 90 of the needle by the rod 4, a subsequent impact of the needle 9 on the guideway 30 will effect a return of the needle 9,90 to its original length. The bent end of the lower part 9 of the reading needle rests with an initial elastic tension on the base or bottom wall of its respective groove 96. This needle end is arranged inclined with respect to the needle shaft. As a result, the frictional pressure is reinforced with an increasing shortening of the entire needle to cause a progressive braking action between the needle 9 and the block 95 when the impact force acts onto the needle 9. With all of the described modified embodiments, the peak force from the impact of the reading needle on the nonperforated portion of the pattern card is broken due to the reading needle being shortened under the brake effect. A further possibility of reducing these impact forces can now consist in absorbing a part of these forces by the pattern card. For example the pattern card 1 can, in particular at the nonperforated portions, be coated with a rubber-elastic mass or a rubber-elastic layer can be arranged between the pattern card cylinder and the pattern card 1 and yields under the impact pressure. The nonperforated portions themselves can also consist directly as pins of elastic material. A different possibility of weakening the impact pressure consists in the pattern cylinder moving during the moment of the impact of the reading needle in the same direction with same, however, at a lower speed. The difference in movement results in a longer duration of time for transmitting the movement energy from the needle to the nonperforated portion of the pattern card to cause the peak forces to be reduced without timely influencing the reading of a perforated portion of the pattern card. Although particular preferred embodiments of the invention have been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.
A dobby with a mechanical reading device for a control card having perforated and nonperforated portions therein according to a pattern. The reading needle of the reading device of the pattern card has yielding elements for the purpose of reducing the impact force of the reading needle onto the pattern card.
3
This is a continuation of application Ser. No. 188,599 filed Sept. 19, 1980, now abandoned. BACKGROUND OF THE INVENTION The invention relates to a sewing machine having an electonic memory storing stitch control data which are sequentially read out from the memory during each rotation of the upper shaft of the sewing machine to control the needle and the feed mechanism and thereby produce a pattern of stitches. More particularly, the invention relates to a sewing machine in which a speed regulating controller can be switched to control the lateral swinging amplitude of the needle. Generally, an electronic sewing machine has a dial knob provided on the front face of the sewing machine, the dial is manually operated to adjust the swinging amplitude of the needle. Such a dial knob can be inconvenient for manual operation such as in the case of embroidery stitching, in which the machine operator is required to freely operate the dial knob while stitching the embroidery. In this case a large lever is preferable. However, it is very difficult to provide such a lever on the front face of a multi-function sewing machine in view of the mounting space, and in view of the structural problem as to the connection between the lever and the printed-circuit electronic elements. At all events, it is not preferable to carryout a stitching operation in a manner that the machine operator manipulates the fabric to be sewn with one hand while operating the needle regulating knob or lever by the other hand. SUMMARY OF THE INVENTION The present invention has been provided to eliminate the foregoing defects and disadvantages of the prior art. It is a basic object of the invention to provide a sewing machine having a speed regulating controller which can be switched to control the needle swinging movement. It is another object of the invention to fix the speed of the sewing machine at a predetermined speed when the speed regulating controller is so switched. It is still another object of the invention to provide a sewing machine of a simple structure and easy operability. Many other features and advantages of the invention will be apparent from the following description of the preferred embodiments in reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS: FIG. 1 is the exterior of a sewing machine which uses the invention. FIG. 2 is a circuit diagram of the invention. FIG. 3 is a flow chart of a program executed by the invention. FIG. 4 is a circuit diagram of another embodiment of the invention, and FIG. 5 is a flow chart of a program executed by the second embodiment of the invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In FIG. 1, the numeral 1 shows a machine housing having a dial 2 provided on the front face thereof for adjusting the stitch width. When the dial 2 is not operated, the stitch width is automatically set in accordance to a standard width specific to a selected stitch pattern. When dial 2 is pushed and then rotated, the stitch width of the pattern is enlarged or reduced proportionally. The numeral 3 is a plug receptacle provided on one side of the machine housing 1 and furnished with a power switch 4 and a conversion switch 5. The numeral 6 is a pedal controller having a foot operated step plate 7. The numeral 8 is a male plug connected to a connector 9 for connecting the controller 6 and a later mentioned control circuit installed within the machine housing 1. In FIG. 2, ROM is a read-only-memory storing stitch pattern control signals and program control signals. CPU is a central processing unit for executing programs. RAM is a random-access-memory for temporarily storing the results and processes of the programs. I/O is an input-output port. ROM, CPU, RAM and I/O constitute a micro computer. PW is a power supply receives AC power from the plug 8 via the power switch 4, and serves as a power source for a machine motor (not shown) and as a power source for the respective circuit elements. SP is a speed control circuit which gives a control signal Vcc to the controller 6 when a group of vertically movable contact elements L are located at their upper positions in the conversion switch 5, and receives at its line A a signal from a wiper C1 of variable resistor VR1. Thus the speed control circuit SP is turned on together with variable resistor VR1, and the speed of the machine drive motor (not shown) is regulated by moving the wiper C1 along the variable resistor VR1 and, at the same time, the positional signal from the wiper C1 is transmitted to the CPU. MR is a stitch width control circuit which is connected to a variable resistor VR2. Variable resistor VR2 is adjusted by means of a dial 2 when the group of contact elements L in the conversion switch 5 are located at the upper positions as shown. The circuit MR and the variable resistor VR2 are turned on when the line B receives the control signal Vcc, and the initial signal from wiper C2 is transmitted to the central processing unit CPU. Thus the stitch width is adjusted by moving the wiper C2 along the variable resistor VR2. The speed control circuit SP and the line G, G of the manually adjustable stitch width control circuit MR are grounded. When the group of contact elements L of the conversion switch 5 are shifted from the upper position to the lower position, the speed control circuit SP is turned off since its input is disconnected and the stitch width control circuit MR is disconnected from the variable resistor VR2 which is manipulated by the control dial 2. As a result, the control function of the variable resistor VR1 by the controller 6 is enabled. Then the micro-computer CPU detects that the speed control circuit SP is seperated from the controller 6, and causes circuit SP to operate the machine drive motor at a predetermined lowspeed. The numeral 9 denotes the connector shown in FIG. 1. Operation of the above mentioned circuit structure will be explained with reference to the flow chart in FIG. 3. When plug 8 is inserted in a wall socket and the power switch 4 is closed, the program control is started, and it is determined whether or not the step plate 7 of the controller 6 is depressed. That is to say, CPU detects, through the speed control circuit SP or the stitch width control circuit MR, a signal at the initial contact of the wiper C1 which is issued to the variable resistor VR1 when the controller 6 is operated. At the same time, the wiper C1 receives the control signal Vcc. Then the CPU to determines whether the group of contact elements L of the conversion switch 5 are located at their upper position or at their lower position as seen in FIG. 2, which is determined by the fact that the signal has passed through the speed control circuit SP or the stitch width control circuit MR. If the group of contact elements L are located at the upper position, the connections of the elements are as shown in FIG. 2 is provided, and the speed control circuit SP is connected to the controller 6, and controller 6 regulates the rotation speed of the machine drive motor (not shown) in accordance with the position of the wiper C1 relative to the variable resistor VR1 by operation of the step plate 7. On the other hand, the stitch width control circuit MR is made operative when dial 2 is pushed. When the dial 2 is rotated, the wiper C2 is displaced along the variable resistor VR2 and the stitch width is manually controlled, and then the program is returned to the start (RET). When the group of contact elements L are located at the lower position, the variable resistor VR1 of the controller 5 is isolated from the speed control circuit SP, and the stitch width control circuit MR is connected to the variable resistor VR1. When the step plate 7 of the controller 6 is depressed the speed control circuit SP is adjust by CPU to rotate the machine motor at a predetermined low speed. At this time the controller 6 controls the stitches, that is when the wiper C1 is displaced along the variable resistor VR1, it acts on the stitch width control circuit MR for controlling the stitch width. FIG. 4 shows another embodiment of the invention. In FIG. 2, if the group of contact elements L, are located at the lower position, the variable resistor VR2 is cut off. On the other hand if the group of contact elements L in the second embodiment moved to their lower position, the variable resistor VR2 is connected to the speed control circuit SP, so that the rotation speed of the sewing machine may be determined by the resistance value of the variable resistor VR2. When the group of contact elements L are located at the upper position, the effect is the same as in the first embodiment in FIG. 2. Operation of the circuit structure shown in FIG. 4 will be explained with reference to the flow chart in FIG. 5. When the program control is started by closing the source switch 4, the effect is the same with the first embodiment in FIG. 2 as to the detection, of the upper and lower positions of the contact elements L by the CPU, and the operation modes switch in dependence upon the positions of the contact elements L. However, in this embodiment, the speed control circuit SP is connected to the variable resistor VR2 which is operated by the dial 2, when the contact elements L are located at the lower position. Therefore, the resistance value of the variable resistor VR2 determines the rotation speed of the sewing machine when the controller 6 is switched to controlling the stitch width.
In a micro-computer controlled sewing machine a conversion switch is provided which can be switched between a first position and a second position. A manually operable controller, such as a foot pedal, is connected to the conversion switch. The circuit means connects the conversion switch to the micro-computer in the electronic sewing machine. When the conversion switch is in its first position, the operable machine controller will control the rotation speed of the sewing machine. When the conversion is in the second position, the manually operable controller will control the needle swing amplitude.
3
FIELD OF THE INVENTION This present invention relates generally to localization values in a computer resource file, and more particularly to creating a POSIX style locale source file from a plurality of localization values in a computer resource file. BACKGROUND OF THE INVENTION In the computer software marketing and distribution industry, it is advantageous to make computer software available for use that reflects the language and culture of the intended users. A locale source file is a computer resource file typically made available by a developer of a software application to assist in accomplishing this. A locale source file may include a combination of specifications required to configure a software application program for a particular geographic and cultural market. These specifications typically include a language specification to determine and control linguistic manipulation of character strings within the application program. In addition specifications for countries, regions and territories (collectively referred to herein as “country”) define cultural conventions that may vary with languages, cultures or across countries. An example of a cultural convention is a date format identifying in which order the numerals representing day, month and year appear. Other configuration preferences, such as those used to specify mail settings or favorite icons are known in the art, but are typically not included in locale source files but may be included in other forms of personalization support. Locale source files are usually processed into a form that can be readily used by an application program. Compilation of a source form of a locale file is one typical means of producing an object that can be accessed by an application program needing the information provided by the locale file. Ensuring computer application program processing of information according to local cultural and geographical preferences relies on the availability of a locale object for a given combination of language and country. In order to make a locale object available there is a need to have a number of ready-made locale objects or locale source files ready to be compiled. Creating locale source files is typically tedious work requiring significant time and effort on the part of skilled programmers. Compiling objects in anticipation of use also takes time and effort as well as consuming computing resources. Locale objects that have been created but not used or are used infrequently waste computing resources and programmer time. Further locale objects themselves cannot be created until the necessary locale source files on which they are based have been built. It is therefore desirable to have an easier more efficient manner of producing locale source files for use in a computer. SUMMARY OF THE INVENTION Embodiments of the present invention are provided for creating locale source files as they are required from a plurality of localization values in a computer resource file. An embodiment of the present invention may be employed to generate specific locale source files by request or on demand. Results provided by embodiments of the invention typically afford easier more efficient means of making selected locale source files available on a computer as required. In accordance with an aspect of the present invention, there is provided a method for creating a specific POSIX style locale source file on demand suitable for compilation in a computer, said method comprising, receiving a request submitted for said specific POSIX style locale, obtaining a plurality of localization values related to said specific POSIX style locale, determining a category of localization values within said plurality of localization values and selecting process routines dependent upon said category, selectively extracting said localization values pertaining to said category by said selected process routines, storing said extracted localization values into a memory of said computer, and assembling said extracted information into said POSIX style locale source file suitable for compilation. According to another aspect of the present invention, there is provided a system for creating a specific POSIX style locale source file on demand suitable for compilation in a computer, said system comprising, a receiver adapted to receive a request submitted for said specific POSIX style locale, a means for obtaining a plurality of localization values related to said specific POSIX style locale, a means for determining a category of localization values within said plurality of localization values and selecting process routines dependent upon said category, an extractor for selectively extracting said localization values pertaining to said category by said selected process routines, a storage means for storing said extracted localization values into a memory of said computer, and an assembling means for assembling said extracted information into said POSIX style locale source file suitable for compilation. According to yet another aspect of the present invention, there is provided a computer program product having a computer readable medium tangibly embodying computer readable program code for instructing a computer to perform a method for creating a specific POSIX style locale source file on demand suitable for compilation in a computer, said method comprising, receiving a request submitted for said specific POSIX style locale, obtaining a plurality of localization values related to said specific POSIX style locale, determining a category of localization values within said plurality of localization values and selecting process routines dependent upon said category, selectively extracting said localization values pertaining to said category by said selected process routines, storing said extracted localization values into a memory of said computer, and assembling said extracted information into said POSIX style locale source file suitable for compilation. According to yet another aspect of the present invention, there is provided a signal bearing medium having a computer readable signal tangibly embodying computer readable program code for instructing a computer to perform the method for creating a specific POSIX style locale source file on demand suitable for compilation in a computer, said method comprising, receiving a request submitted for said specific POSIX style locale, obtaining a plurality of localization values related to said specific POSIX style locale, determining a category of localization values within said plurality of localization values and selecting process routines dependent upon said category, selectively extracting said localization values pertaining to said category by said selected process routines, storing said extracted localization values into a memory of said computer, and assembling said extracted information into said POSIX style locale source file suitable for compilation. Other aspects and features of the present invention will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: FIG. 1 is a hardware overview of a computer system, exemplary of an embodiment of the present invention; FIG. 2 is a block diagram of a high level view of components of an embodiment of the present invention; FIG. 3 is flow diagram showing the overview of the process used in conjunction with the components of FIG. 2 ; and FIG. 4 is a flow diagram detailing operations of elements 330 and 340 of FIG. 3 . Like reference numerals refer to corresponding components and steps throughout the drawings. It is to be expressly understood that the description and the drawings are only for the purpose of illustration and as an aid to understanding, and are not intended as a definition of the limits of the invention. DETAILED DESCRIPTION FIG. 1 depicts, in a simplified block diagram, a computer system 100 suitable for implementing embodiments of the present invention. Computer system 100 has a central processing unit (CPU) 110 , which is a programmable processor for executing programmed instructions, such as instructions contained in utilities (utility programs) 126 stored in memory 108 . Memory 108 can also include hard disk, tape or other storage media. While a single CPU is depicted in FIG. 1 , it is understood that other forms of computer systems can be used to implement the invention, including multiple CPUs. It is also appreciated that the present invention can be implemented in a distributed computing environment having a plurality of computers communicating via a suitable network 119 , such as the Internet. CPU 110 is connected to memory 108 either through a dedicated system bus 105 and/or a general system bus 106 . Memory 108 can be a random access semiconductor memory for storing language and culture data for each country and culture such as input file 122 and scripts 124 . Scripts 124 provide routines to process input file 122 creating output locale source file 128 . Memory 108 is depicted conceptually as a single monolithic entity but it is well known that memory 108 can be arranged in a hierarchy of caches and other memory devices. FIG. 1 illustrates that operating system 120 , input file 122 , scripts 124 , locale source file 128 and utilities 126 , may reside in memory 108 . Operating system 120 provides functions such as device interfaces, memory management, multiple task management, and the like as known in the art. CPU 110 can be suitably programmed to read, load, and execute instructions of operating system 120 , scripts 124 and instructions of utilities 126 . Computer system 100 has the necessary subsystems and functional components to implement testing of locale files as will be discussed later. Other programs (not shown) include server software applications in which network adapter 118 interacts with the server software application to enable computer system 100 to function as a network server via network 119 . General system bus 106 supports transfer of data, commands, and other information between various subsystems of computer system 100 . While shown in simplified form as a single bus, bus 106 can be structured as multiple buses arranged in hierarchical form. Display adapter 114 supports video display device 115 , which is a cathode-ray tube display or a display based upon other suitable display technology which may be used to depict test results. The Input/output adapter 112 supports devices suited for input and output, such as keyboard or mouse device 113 , and a disk drive unit (not shown). Storage adapter 142 supports one or more data storage devices 144 , which could include a magnetic hard disk drive or CD-ROM drive although other types of data storage devices can be used, including removable media for storing input file 122 and the output of scripts 124 being locale source file 128 . Adapter 117 is used for operationally connecting many types of peripheral computing devices to computer system 100 via bus 106 , such as printers, bus adapters, and other computers using one or more protocols including Token Ring, LAN connections, as known in the art. Network adapter 118 provides a physical interface to a suitable network 119 , such as the Internet. Network adapter 118 includes a modem that can be connected to a telephone line for accessing network 119 . Computer system 100 can be connected to another network server via a local area network using an appropriate network protocol and the network server can in turn be connected to the Internet. FIG. 1 is intended as an exemplary representation of computer system 100 by which embodiments of the present invention can be implemented. It is understood that in other computer systems, many variations in system configuration are possible in addition to those mentioned here. In one embodiment of the invention the process involves traversing the input file of localization information while searching for values that announce the location of categories of interest. When such a category is encountered a selection of an appropriate script resource may be made. The chosen script resource is optimized for the particular category and entries within that category to be processed. For example, in an embodiment of the invention, to process a date and time category, upon locating such a category, one of a plurality of possible script modules may be invoked dependent upon the particular category being processed. A need for specialized script modules will become apparent through later discussion of the process. Standard utilities (as in utilities 126 of FIG. 1 ) available on platforms are used in conjunction with the scripts. Standard utilities used include those for substring, case mapping, Unicode conversion, string and character comparison and table lookup operations. Comparisons may involve a user or may be programmatic in nature using a comparator in conjunction with reference data. An exemplary process of an embodiment of the present invention consists of a series of operations typically as follows: “prepare”, “process”, “compare” and “generate”. Upon receipt of a request for a locale source to be created, a “prepare operation” obtains localization data as input, while a “process” operation invokes appropriate scripts to parse, and analyse the localization data to produce an output in combination with templates, as required by the category being processed, to produce a well formed output. A “compare operation” is used on the parsed data of the prepare operation to compare against selected reference strings as needed. In a “generate” operation, previous output that may have been stored as logical units will be consolidated with the addition of supporting LC_CTYPE and LC_COLLATE data into a locale source file. The “prepare process” pulls the category elements out of the localization data file syntax and environment and into a simple text form for collection into respective category entries. Output fields are used to store the collection results of the prepare process in a combination of name-value pairs. Script modules which process the input file use announcement strings of the various categories and elements to indicate what is to be processed. Obtaining a match confirms the category to be processed and allows the main routine to selectively and more correctly process the associated values. The result of processing is a hierarchical collection of values. The highest level is the root or locale identifier for the whole collection. The next level is the various category identifiers and finally the associated substrings and related values. Referring to FIG. 2 is a block diagram depicting an overview of the components in an embodiment of the invention performed on an exemplary system of FIG. 1 . Input file 122 is processed by scripts 124 in conjunction with utilities 126 to produce data output. This data output is passed through generator 125 to produce output of locale source file 128 . Scripts 124 , utilities 126 and generator 125 may be provided by hardware, software or a combination of both means. Referring now to FIG. 3 is a flow diagram showing the overall process as performed by the components as shown in FIG. 2 . Processing begins in operation 300 where any necessary setup may be performed and moves to operation 305 . During operation 305 a request for a specific locale source file to be created is received. Upon receipt of the request, the request is examined for completeness. A well-formed request needs to specify a desired locale. One manner is to provide an “id_ID” to correctly specify the locale. The use of such an identifier is common in the art where “id” represents language and “ID” represents country or territory. Receipt of the request causes the process to move to operation 310 during which is obtained input file 122 of FIG. 1 . If there is more than one input file they are merged. For example, an input file may be a logical file consisting of many input files wherein files may be segmented to contain a portion of the required locale information. Once obtained and merged if necessary, a scripting operation 320 is performed to determine the category being processed and which routines to select based on the category determined. Extracting specific values occurs during operation 330 , wherein these values are then stored in a memory during operation 340 in a predetermined form for later use. The process is repeated for each category of input file 122 until all elements have been processed. Intermediate results may be stored in any form, as is known in the art, providing suitable retrieval, such as but not limited to, arrays, vectors, tables and lists. Then during operation 350 a determination is made regarding existence of more categories to process. If during operation 350 it is determined that more categories exist to be processed, operations will move to operation 320 again where processing will occur as before. If there are no more categories to process, as determined during operation 350 , processing will move to operation 360 . During operation 360 generator 125 of FIGS. 1 and 2 assembles the output from the previous operations. Having then assembled all output which may include adding other files such as those for LC_CTYPE and LC_COLLATE, processing moves to end at operation 370 . Referring to FIG. 4 details of scripting operation 330 will now be described. Scripting operation 330 uses a readily available scripting facility as is known in the art. Scripting is a form of programming which is powerful yet relatively simple. The scripting functions are knowledgeable of the predefined syntax of input file 122 and are able to iterate through the file invoking various process modules (other specialized scripts) to perform selective actions dependent upon respective portions. For example, an input portion of locale file 122 is typically announced according to convention using a comment string of the form “LC_name” (without quotation marks) wherein the name is the identifier of the specific category, such as LC_Monetary denoting currency information. Contained within, is the actual localization information of interest as a plurality of elements. Dependent on the usage context of the value being processed a respective module or scripting function is invoked to process the associated string of data. The string of data may be composed in a series of name-value pair's format. An example of which may be seen later in connection with process details. Before any locales can be created, a validity check should be performed on the localization data to ensure the information for the country/language pair for which the locale will be created has been verified. In this manner, the integrity of the data in the composed locale is ensured. The following described order is not required but merely shown as an example. The order of categories does not affect the outcome. It may be easier to understand the process by looking at the outcome and then the process to produce that outcome. The file containing a plurality of localization values can be stored in a number of suitable formats such as arrays, tables or lists. It is important however to have the information required in a form that provides efficient retrieval of requested data. For these examples it is assumed that the localization information has been provided in a single file restricted to that of a single locale. Other cases containing localization data for a plurality of locales requires a filtering step to reduce the data to the specifically requested locale of interest first. Further it is assumed that the use of LC-CTYPE and LC_COLLATE category data is by additional means such as separate files. These two files will be added to the output created by the described process to produce the requested locale source file. One structure within the locale source file to be created deals with monetary formats and is known as the LC_Monetary category. For example the typical conventional format of the monetary information in a locale source file such as 128 of FIG. 1 is as follows: ############# LC_MONETARY ############# ########################################################################### ## id_ID example of a positive monetary value: Rp. 1.234.567,89 ## ## id_ID example of a negative monetary value: -Rp. 1.234.567,89 ## ########################################################################### int_curr_symbol “<I><D><R><space>” currency_symbol “<R><p><period>” mon_decimal_point “<comma>” mon_thousands_sep “<period>” mon_grouping 3 positive_sign “” negative_sign “<hyphen>” int_frac_digits 2 frac_digits 2 p_cs_precedes 1 p_sep_by_space 1 n_cs_precedes 1 n_sep_by_space 1 p_sign_posn 1 n_sign_posn 1 END LC_MONETARY This segment of locale source file 128 typically begins with an LC_Monetary and end with an END LC_Monetary statement. Between these two statements are other statements defining the attributes of the segment in particular detail. Each element within the segment is a name-value pair having a descriptor or label as an aid in understanding the context of use. The name-value pairing also allows for more efficient processing during the creation process of the locale source file 128 from the raw localization information of input file 122 of FIG. 1 . For simplicity the name of the output name value pair is also used as a field name in input file 122 . Such a linkage is not required but is handy for this example. The addition of the two statements having id_ID is related to self-checking information and processing used in the creation of this specific category. A skilled practitioner may copy similar information directly into the output file as another means for visual checking of the output file. The relative positioning of elements within a category is used to create a template that is then filled with extracted information during the creation process. The monetary information category typically contains the names in the following paragraphs. The following process steps as shown in FIG. 4 are illustrative of an embodiment of the present invention. The process steps detail operations within operations 330 and 340 of FIG. 3 , particularly operation 330 beginning with operation 310 . During operation 310 one or more files is obtained and merged to provide necessary localization values to satisfy the request to create a specific locale source file. Through a series of operations each category of the locale source file is addressed beginning with 330 -A for monetary processing, 330 -B for numeric processing, 330 -C for date and time processing and finally with 330 -D for yes/no information. Within each 330 - xy operation is a series of smaller sub-operations denoted by 330 - xy , where x is one of A-D denoting the category to which it applies and where y is a sequential number indicating the operation relative to others in the category set. Next is operation 330 -A 1 during which is obtained the int_curr_symbol information by extracting the ISO 4217 Alphabetic Currency Code from the “Monetary_ISO4217_Alpha_Code” field of the monetary information in the input file. Next is extracted the examples contained in the fields “Monetary_ISO4217_Positive_Format” and “Monetary_ISO4217_Negative_Format”. These fields contain examples, in proper format, monetary quantity for both positive and negative formats using ISO 4217 Alphabetic Currency Code. Having obtained the example information parse the extracted strings to determine what currency code is used for both formats and compare the two cases against each other. If they are the same, continue with processing; otherwise, raise a flag and stop. If the examples compare favorably, compare the currency code of the examples with the currency code obtained in first step. If they are the same, continue; otherwise, raise a flag and stop. If the currency codes compared favorably surround each letter of the alphabetic currency code with a pair of angle brackets. Additionally parse either of the positive or negative examples to determine the character separating the alphabetic currency code from the actual monetary quantity and append the separating character to the end of the currency code. Next during 330 -A 2 obtain the currency_symbol by extracting the Currency Symbol from the Monetary_NAT_Currency_Symbol” field. Then extract the examples contained in the fields “Monetary_NAT_Positive_Format” and “Monetary_NAT_Negative_Format” for both positive and negative formats. Parse the extracted strings from the examples to determine the currency symbol used and compare that value with the currency symbol obtained in the first operation. If they are the same, continue; otherwise, raise a flag and stop. If the currency symbol is in graphical form, it must be replaced with it's corresponding alphabetic name and finally add quotes to the currency symbol. Next during operation 330 -A 3 obtain the mon_decimal_point by extracting the Decimal Separator from the “Monetary_NAT_Decimal_Separator” field. Next extract the examples contained in the fields “Monetary_NAT_Positive_Format” and “Monetary_NAT_Negative_Format” for both positive and negative format. Then parse the extracted strings of the examples to determine the decimal separator for each case and compare them. If they are the same, continue; otherwise, raise a flag and stop. Further, if the decimal separator is in graphical form, it must be replaced with its corresponding alphabetic name. Then compare the decimal separator from the example with the one obtained in the first operation. If they are the same, continue; otherwise, raise a flag and stop. Finally add quotes to the decimal separator. Next during operation 330 -A 4 obtain the mon_thousands_sep by extracting the Thousands' Separator from the “Monetary_NAT_Thousands_Separator” field. Then extract the examples contained in the fields “Monetary_NAT_Positive_Format” and “Monetary_NAT_Negative_Format” for both positive and negative formats. Next parse the extracted strings of the examples for both positive and negative format to determine the thousands' separator used in each case. They should be the same for both formats. If they are not, raise a flag and stop. If the thousands separator is in graphical form, is must be replaced with its corresponding alphabetic name. Then compare the thousands separator obtained form the examples with the one obtained in the first operation. If they are the same, continue; otherwise, raise a flag and stop. Finally add quotes to the thousands separator. Next during operation 330 -A 5 obtain the mon_grouping, by extracting the value contained in the “Monetary_NAT_Grouping” field. Next extract the examples contained in the fields “Monetary_NAT_Positive_Format” and “Monetary_NAT_Negative_Format” for both positive and negative formats. Then parse the extracted strings of the examples to determine what grouping is used for both formats. They should be the same for both formats. Compare the value from the example format with the one obtained in the first operation. If they are the same, continue; otherwise, raise a flag and stop. Next during operation 330 -A 6 obtain the positive_sign extract the value in the “Monetary_NAT_Positive_Sign” field. Next extract the example contained in the “Monetary_NAT_Positive_Format” field for the positive format. Then parse the extracted value in the examples to determine the positive sign and compare it with the positive sign value obtained in the first operation. If they are the same, continue; otherwise, raise a flag and stop. Next during operation 330 -A 7 obtain the negative_sign by extracting the value in the “Monetary_NAT_Negative_Sign” field. Next extract the example contained in the “Monetary_NAT_Negative_Format” for the negative format. Then parse the extracted string from the examples to determine the negative sign and compare it with the negative sign value obtained in the first operation. If they are the same, continue; otherwise, raise a flag and stop. Next during operation 330 -A 8 obtain the int_frac_digits by extracting the examples contained in the fields “Monetary_ISO4217_Positive_Format” and “Monetary_ISO4217_Negative_Format”. Then parse the extracted strings for both formats to determine the number of decimal digits for each case and compare against one another. If they are the same, continue; otherwise, raise a flag and stop. Next during operation 330 -A 9 obtain the frac_digits by extracting the value contained in the field Monetary_NAT_Digits_AfterDecimal”. Next extract the examples contained in the fields “Monetary_NAT_Positive_Format” and “Monetary_NAT_Negative_Format” for both positive and negative format. Then parse the extracted strings in both formats to determine the number of decimal places. This value should be the same for both formats. If they are not, raise a flag and stop. Then compare the results from the examples with the value obtained in the first operation. If they are the same, continue; otherwise, raise a flag and stop. Next during operation 330 -A 10 obtain the p_cs_precedes by extracting the value contained in the Monetary_NAT_Positive_Format” field for the positive format. Then parse the extracted string to determine the location of the currency symbol. If the symbol appears before the positive formatted monetary quantity, p_cs_precedes is set to 1; otherwise, it is set to 0. Next during operation 330 -A 11 obtain the p_sep_by_space by extracting the value contained in the “Monetary_NAT_Positive_Format” field for the positive format. Then parse the extracted string to determine if there is any space separating the currency symbol from the positive formatted monetary quantity. P_sep_by_space is set to 0 if no space exists, otherwise set to 1 if a space separates the symbol from the value, and set to 2 if a space separates the symbol and the sign string, if adjacent. Next during operation 330 -A 12 obtain the n_cs_precedes by extracting the value contained in the “Monetary_NAT_Negative_Format” field for the negative format. Then parse the extracted string to determine the location of the currency symbol. If the symbol appears before the negative formatted monetary quantity, n_cs_precedes is set to 1; otherwise, it is set to 0. Next during operation 330 -A 13 obtain the n_sep_by_space by extracting the value contained in the “Monetary_NAT_Negative_Format” field for the negative format. Then parse the extracted string to determine if there is any space separating the currency symbol from the negative formatted monetary quantity. N_sep_by_space is set to 0 if no space exists, set to 1 if a space separates the symbol from the value, and set to 2 if a space separates the symbol and the sign string, if adjacent. Next during operation 330 -A 14 obtain the p_sign_posn by extracting the value contained in the “Monetary_NAT_Positive_Format” field for the positive format. Then parse the extracted value to determine the positioning of the positive sign for the nonnegative formatted monetary quantity. P_sign_posn is set to 0 if parentheses enclose the quantity and the currency symbol, set to 1 if the sign string precedes the quantity and the currency symbol, set to 2 if the sign string succeeds the quantity and the currency symbol, set to 3 if the sign string immediately precedes the currency symbol, and set to 4 if the sign string immediately succeeds the currency symbol. Next during operation 330 -A 15 obtain the n_sign_posn by extracting the value contained in the “Monetary_NAT_Negative_Format” field for the negative format. Then parse the value to determine the positioning of the negative sign for the negative formatted monetary quantity. N_sign_posn is set to 0 if parentheses enclose the quantity and the currency symbol, set to 1 if the sign string precedes the quantity and the currency symbol, set to 2 if the sign string succeeds the quantity and the currency symbol, set to 3 if the sign string immediately precedes the currency symbol, and set to 4 if the sign string immediately succeeds the currency symbol. The collection of localization values for the monetary category is complete. Another category to be created in the locale source file is the LC_NUMERIC category shown as follows: ############# LC_NUMERIC ############# ########################################################### ## pt _PT example of a positive numeric value: 1.234.567,89 ## ## pt _PT example of a negative numeric value: −1.234.567,89 ## ########################################################### decimal_point “<comma>” thousands_sep “<period>” grouping 3 END LC_NUMERIC As with the LC_Monetary category, this category begins with a statement announcing the data contained within LC_Numeric and ends with a corresponding end statement. The field names mentioned below are typically contained in the numeric information category. Next during operation 330 -B 1 obtain the decimal_point by extracting the value contained in the “Numeric_Decimal_Separator” field. Then extract the examples contained in the fields “Numeric_Positive_Format” and “Numeric_Negative_Format” for both formats. Next parse the extracted strings of the examples to determine the decimal separator for each format. In each case, they should be the same. If they are not, raise a flag and stop. Then compare the decimal separator obtained in previous operation with the decimal separator from the first operation. If they are the same, continue; otherwise, raise a flag and stop. Next during operation 330 -B 2 obtain the thousands_sep by extracting the value contained in the “Numeric_Thousands_Separator” field. Next extract the examples contained in the fields “Numeric_Positive_Format” and “Numeric_Negative_Format” for both positive and negative format. Next parse the extracted values for both formats to determine the thousand separator is in each case. Then compare thousands separator from the example with the extracted thousands separator obtained in the first operation. If they are the same, continue; otherwise, raise a flag and stop. Next during operation 330 -B 2 obtain the Grouping, by extracting the value in the “Numeric_Grouping” field. Then extract the examples contained in the fields “Numeric_Positive_Format” and “Numeric_Negative_Format” for both positive and negative format. Then parse the extracted values for both formats to determine the grouping. In either case, it should be the same as the one obtained in the first operation. If they are not the same, raise a flag and stop. This completes the processing need to create the category LC_NUMERIC in the locale source file output. Another locale category deals with time and date settings and is known as LC_TIME. As with the previous categories the LC_Time category also begins and ends with proper statements as shown. ############# LC_TIME ############# ########################################################################## ## Order of abbreviated days: <Sun> <Mon> <Tue> <Wed> <Thu> <Fri> <Sat> ## ########################################################################## abday   “<M><i><n><g><g><u>”;\       “<S><e><n><i><n>”;\       “<S><e><l><a><s><a>”;\       “<R><a><b><u>”;\       “<K><a><m><i><s>”;\       “<J><u><m><a><t>”;\       “<S><a><b><t><u>” ######################################################################### ## Order of days: <Sunday> <Monday> <Tuesday> <Wednesday> <Thursday> ## ##    <Friday> <Saturday>                       ## ######################################################################### day    “<M><i><n><g><g><u>”;\      “<S><e><n><i><n>”;\      “<S><e><l><a><s><a>”;\      “<R><a><b><u>”;\      “<K><a><m><i><s>”;\      “<J><u><m><a><t>”;\      “<S><a><b><t><u>” ######################################################################### ## Order of abbreviated months: <Jan> <Feb> <Mar> <Apr> <May> <Jun> ## ##     <Jul> <Aug> <Sep> <Oct> <Nov> <Dec>            ## ######################################################################### abmon   “<J><a><n><u><a><r><i>”;\       “<F><e><b><r><u><a><r><i>”;\       “<M><a><r><e><t>”;\       “<A><p><r><i><l>”;\       “<M><e><i>”;\       “<J><u><n><i>”;\       “<J><u><l><i>”;\       “<A><g><u><s><t><u><s>”;\       “<S><e><p><t><e><m><b><e><r>”;\       “<O><k><t><o><b><e><r>”;\       “<N><o><v><e><m><b><e><r>”;\       “<D><e><s><e><m><b><e><r>” ########################################################################## ## Order of months: <January> <February> <March> <April> <May> <June> ## ##    <July> <August> <September> <October> <November>       ## ##    <December>                           ## ########################################################################## mon    “<J><a><n><u><a><r><i>”;\      “<F><e><b><r><u><a><r><i>”;\      “<M><a><r><e><t>”;\      “<A><p><r><i><l>”;\      “<M><e><i>”;\      “<J><u><n><i>”;\      “<J><u><l><i>”;\      “<A><g><u><s><t><u><s>”;\      “<S><e><p><t><e><m><b><e><r>”;\      “<O><k><t><o><b><e><r>”;\      “<N><o><v><e><m><b><e><r>”;\      “<D><e><s><e><m><b><e><r>” ####################################################################### ## id_ID example of below format is: Monday, 23 Jun 14:59:33, 1997   ## ####################################################################### d_t_fmt “%A %e %b %H<colon>%M<colon>%S %Y” ##################################################### ## id_ID example of below date format is: 10/04/98 ## ##################################################### d_fmt “%d<slash>%m<slash>%y” ###################################################### ## id_ID example of below time format is: 14:59:33  ## ###################################################### t_fmt “%H<colon>%M<colon>%S” am_pm “”;“” ###################################################### ## id_ID example of below time format is: 14:59:33  ## ###################################################### t_fmt_ampm “%H<colon>%M<colon>%S” ######################################################## ## id_ID example of below date format is: 24 Jun 1997 ## ######################################################## nlldate “%d %b %Y” END LC_TIME The field names discussed next are typically contained in the date or calendar information section unless otherwise stated. Next during operation 330 -C 1 obtain the abbreviated days of the week, abday by extracting the abbreviated weekday names in Native language from the fields “NTV_Abbreviated_???” where the “???” represents the abbreviated weekday names in English such as Mon thru Sun. If the abbreviated weekday names are not displayable, extract their UCS-2 equivalent from the fields “U_NTV_Abrreviated_???” where the “???” represents the same values as in the previous operation. If the names are displayable replace any non-alphanumeric character with its UCS-2 value and add a pair of angle brackets to each letter in the abbreviated weekday name. If UCS-2 values are extracted, leave the abbreviated weekday names untouched. Put double quotes around each of the abbreviated weekday names. Next during operation 330 -C 2 obtain the weekdays, day by extracting the full weekday names in Native language from the fields “NTV_???????” where the “???????” represents the full weekday names in English such as Monday through Sunday. If the names are not displayable, extract their UCS-2 equivalent from the fields “U_NTV_???????” where “?????????” represents the full weekday names as in the previous operation. If the names are displayable replace any non-alphanumeric character with its UCS-2 value and add a pair of angle brackets to each letter in the weekday name. If UCS-2 values are extracted, leave the full weekday names untouched. Place double quotes around each of the full weekday names. Next during operation 330 -C 3 obtain the abbreviated month names, abmon by extracting the abbreviated month names in Native language from the fields “NTV_Abbreviated_???” where the “???” represents the abbreviated month names in English such as January, February, and others. If the abbreviated month names are not displayable, extract their UCS-2 equivalent from the fields “U_NTV_Abbreviated_???” where the “???” represents the same value as in the previous operation. If the names are displayable, replace any non-alphanumeric character with its equivalent UCS-2 value and add a pair of angle brackets to each letter in the abbreviated month names. If the UCS-2 values are extracted, leave the abbreviated month names untouched. Put double quotes around each abbreviated month name. Next during operation 330 -C 4 obtain the full month name mon by extracting the full month names in Native language from the fields “NTV_???????” where the “???????” represents the full month names in English such as January through December. If the full month names are not displayable, extract their UCS-2 equivalent from the fields “U_NTV_????????” where the “?????????” represents the same value as in the previous operation. If the names are displayable and are extracted properly, replace any non-alphanumeric character with its UCS-2 value and add a pair of angle brackets to each letter in the month name. If UCS-2 values are extracted, leave the full month names untouched. Put double quotes around each full month names. All field names discussed next are typically contained in the date and time Information section unless otherwise stated. Next during operation 330 -C 5 obtain the date format d_t_fmt by extracting the value from the “Date_NTV_Full_Format” field. Then parse the extracted value to determine the day and month name. Next extract the full weekday name for Tuesday in native language from the field “NTV_Tuesday” in the Calendar section. Extract the full month name for April in native language from the field “NTV_April” in the Calendar section. Compare the parsed weekday name with the extracted value Tuesday from the previous operation. If the comparison is equal then, continue; otherwise, raise a flag and stop. Next compare the parsed month name with the extracted month value in the previous operation. If they are the same, then continue; otherwise, raise a flag and stop. Next parse the extracted string in from the first operation to determine the positioning of the day, date, month and year in the date format. Then create a string with day replaced by % A, date replaced by % d, month replaced by % B and year replaced by % Y in the order that they appear in the Full Date Format. Finally repeat similar steps for the Time format and append the resulting string to the one from the previous operation. Next during operation 330 -C 6 obtain a common date format, d_fmt by extracting the value from the Date_NTV_Common_Format” field. Parse the extracted string from the previous operation to determine the date separator and compare it with the value specified in the “Date_Short_Separator” field. If they are the same, continue; otherwise, raise a flag and stop. Next parse the extracted string from the first operation to determine the positioning of the date, month and year. Create a string with date replaced by % d, month replace by % m and year replaced by % Y in the order that they appear in the Common Date Format. Next during operation 330 -C 7 obtain the full time format t_fmt by extracting the value from the “Time_NTV_Full_Format” field. Extract the value from the “Time_Separator” field. Parse the extracted string in the first operation to determine the time separator and compare it with the time separator second operation. If they are the same, continue; otherwise, raise a flag and stop. Next extract the value from the “Time — 24 hr_Clock_Used” field. If the value is No, parse the string from the first operation to determine the value for the afternoon string and compare it with the afternoon string specified in the “Time_NTV_Afternoon_String”. If they are the same, continue; otherwise, raise a flag and stop. Next parse the string from the first operation to determine the location of the hour, minute and second. Create a string with hour replaced by % H, minute replaced by % M and second replaced by % S in the order that they appear in the Full Time Format. This then becomes the value for the t_fmt keyword. Next during operation 330 -C 8 obtain the am-pm indicator, am_pm by extracting the value from the “Time — 24 hr_Clock_Used” field. If value is Yes, am_pm is set to an empty string (i.e. “ ”) If value is No, extract “Morning string in native language” and “Afternoon string in native Language”. Compare the afternoon string with the one used in the Full Time Format. If they are the same, continue; otherwise, raise a flag and stop. Next during operation 330 -C 9 obtain t_fmt_ampm by extracting the value from the ‘Time — 24 hr_Clock_Used” field. If value is Yes, t_fmt_ampm is set to null (i.e. empty string) If value is No, extract the value from the “Time_NTV_Common_Format” field. Parse the string to determine what the “Time Separator” is and compare it with the value specified in the “Time Separator” field. If they are the same, continue; otherwise, raise a flag and stop. Next parse the extracted string in third operation to determine the positioning of the hour, minute and second. Next create a string with hour replaced by % I, minute replaced by % M and second replaced by % S in the order that they appear in the Common Time Format. Parse the Common Time Format string to determine the positioning of the afternoon string. Either prefix or append % p to the string in the previous operation depending on the order the afternoon string appears. This completes processing of localization values for the data and time category of the locale source file. When dealing with yes and no responses, yet another category of the locale source file, LC_MESSAGES is used. ############# LC_MESSAGES ############# yesexpr “{circumflex over ( )}([<y><Y>]\[<y><Y>][<a><A>])” noexpr “{circumflex over ( )}([<t><T>]\[<t><T>][<i><I>][<d><D>][<a><A>][<k><K>])” END LC_MESSAGES Next during operation 330 -D 1 obtain the yes expression yesexpr by extracting the values contained in the “Affirmative_Response_Short” field. Put angle bracket around the upper and lower case of each letter that appears in the short responses and enclose it within square brackets. For example, the affirmative short response for the above example is y. Both the upper and lower case Y is enclosed in angle brackets, which is further enclosed in square brackets. Next extract the values contained in the “Affirmative Response” field Repeat the second operation for the string value. Then append the resultant string in the previous operation to the string from the first operation with a vertical bar separating the two. Next enclose the whole string in round brackets. Prefix a ^ (i.e. Circumflex accent) in front of the string and put quotes around it. Next during operation 330 -D 2 obtain the related no expression, noexpr by extracting the values contained in the “Negative_Responses_Short” field. Put angle bracket around the upper and lower case of each letter that appears in the short responses and enclose it in square brackets. For example, the negative short response for the above example is t. Both the upper and lower case t is enclosed in angle brackets, which is further enclosed in square brackets. Then extract the values contained in the “Negative_Response” field Repeat the second operation for the extracted value. Append the resultant string from the previous operation to the string in step 1 with a vertical bar separating the two strings. Enclose the whole string in round brackets. Finally prefix a ^ (i.e. Circumflex accent) in front of the string and put quotes around it. This completes processing of the yes/no expressions for the LC_MESSAGES category of the locale source file. Processing would move to operation 360 during which assembly would take place to collect the category definitions created in previous stages of the just described process. As mentioned earlier the local source file would be composed of output as just described plus files containing LC_CTYPE and LC_COLLATE. A simple text editor as found on systems may be used to perform the necessary addition of the two files to the just produced locale category entries. Although the invention has been described with reference to illustrative embodiments, it is to be understood that the invention is not limited to these precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art. All such changes and modifications are intended to be encompassed in the appended claims.
A method for creating a specific POSIX style locale source file, on demand, suitable for compilation in a computer is provided the method comprising, receiving a request submitted for the specific POSIX style locale, and obtaining a plurality of localization values related to the specific POSIX style locale. Next, determining a category within the plurality of localization values and selecting process routines dependent upon the category, and then selectively extracting the category information. After extracting the category information is stored into a memory of the computer. A determination is made regarding more categories to process, which might result in processing the remaining categories, otherwise assembling the extracted information into the POSIX style locale source file. Assembling may entail addition of no files or files such as LC-CTYPE and LC_COLLATE to form a locale source suitable for compilation.
6
BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to a reflector for bicycles and similar vehicles, and particularly to a multi-surface reflector which appears to be flashing due to movement of a plurality of reflector surfaces relative to a predetermined observation point or points of reference. 2. Description of the Prior Art It is generally known to provide bicycles and similar vehicles with reflector devices which have a reflecting surface movable with respect to the frame of reference of the bicycle in order to create a flashing effect when the reflecting surface is viewed from a point outside of the frame of reference of the bicycle. U.S. Pat. Nos. 3,478,713, issued Nov. 18, 1969 to B. L. Brames; 3,528,721, issued Sept. 15, 1970 to F. J. LaLonde; and 2,741,948, issued Apr. 17, 1956 to G. D. Parker; disclose various examples of bicycle reflectors. More specifically, U.S. Pat. No. 2,741,948 discloses a device which is driven from the spokes of a wheel of a bicycle, while U.S. Pat. No. 3,478,713 discloses a device which is driven by frictional contact with the side of a tire of the bicycle. U.S. Pat. No. 3,528,721 further discloses a device which is driven by frictional contact with the periphery of a tire of the bicycle. In addition, it is also known to provide reflecting devices which are rotated by wind or similar forces, an example of which can be found in U.S. Pat. No. 3,292,569, issued Dec. 20, 1966 to G. T. Trigilio. It is also known to rotate a reflector by means of a suitable electrical or other motor, as can be found in U.S. Pat. No. 3,633,161, issued Jan. 4, 1972 to C. W. Price. SUMMARY OF THE INVENTION It is an object of the present invention to provide a reflector for bicycles and similar vehicles which is positively driven in a simple yet reliable manner. It is another object of the present invention to provide a bicycle reflector which is positively driven by rotation of a rear wheel, or the like, of a bicycle. It is yet another object of the present invention to provide a bicycle reflector which can be mounted in such a manner as to be arranged close in to the frame of the bicycle so as to be protected from damage during mishaps involving the bicycle. It is a still further object of the present invention to provide a bicycle reflector which employs a multi-surface reflector element arranged for irregular movement relative to the reflector per se in order to create a flashing effect for the reflector. These and other objects are achieved according to the present invention by providing a rotatable multi-surface reflector having: a rotatable reflector assembly mounted on a vehicle; a transmission mounted on a wheel of the vehicle for moving the reflector assembly as a function of an angular speed of the wheel; and a connecting arrangement attached to the reflector assembly and to the transmission for operably connecting the transmission to the assembly. Preferably, the transmission includes a ring gear mounted on the spokes of the wheel of the vehicle for rotation coaxially with the wheel. The connecting arrangement can take one of at least two forms depending upon the disposition of the reflector assembly on the vehicle. If the reflector assembly is mounted on the frame of a bicycle directly behind the seat of the bicycle, a flexible drive shaft forms the connecting arrangement, while in the event the reflector assembly is mounted on the frame of a bicycle directly adjacent the hub of the, for example, rear wheel of the bicycle, a rigid shaft assembly can be employed as a coupling between the ring gear and the reflector assembly. The reflector assembly advantageously includes a base having affixed thereto a bracket which attaches the base to the frame of a bicycle, and the like. A reflector element is rotatably mounted on the base, with a converter device being mounted on the base and connected to the connecting arrangement and to the reflector element for imparting an irregular motion to the reflector element. According to one preferred embodiment of the invention, the converter means includes a Geneva mechanism arranged for converting the circular motion transmitted from the wheel of the vehicle into an intermittent uni-directional motion. Conversely, another preferred embodiment of the present invention provides for a crank and rocker four link mechanism which imparts an oscillating motion to the reflector element. The reflector element advantageously includes a transparent enclosure mounted on a base of the reflector assembly, in which the converter arrangement is housed, and a hollow prism having a pair of parallel end faces and at least three side faces, the prism supported by the converter arrangement and journaled on and disposed within the enclosure. The prism is constructed from reflective material, with each side face of the prism advantageously being provided with a different color in order to enhance the flashing effect obtained by the reflector assembly. These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary, side elevational view showing a preferred embodiment of a bicycle reflector according to the present invention mounted immediately behind the seat of a bicycle. FIG. 2 is a fragmentary, rear elevational view showing the bicycle reflector arrangement set forth in FIG. 1. FIG. 3 is an enlarged, fragmentary, sectional view taken generally along the line 3--3 of FIG. 1. FIG. 4 is a sectional view taken generally along the line 4--4 of FIG. 3. FIG. 5 is a sectional view, partly broken away for clarity, taken generally along the line 5--5 of FIG. 3. FIG. 6 is a fragmentary, perspective view taken generally along the line 6--6 of FIG. 3. FIG. 7 is a sectional view, partly broken away for clarity, similar to FIG. 5, but showing another embodiment of the present invention. FIG. 8 is a fragmentary, side elevational view showing still another embodiment of a bicycle reflector according to the present invention. FIG. 9 is a fragmentary, rear elevational view showing the embodiment of FIG. 8. DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotatable multi-surface reflector 10 for bicycles, and the like, is shown mounted on the rear portion of a conventional bicycle 12. This reflector 10 includes a rotatable reflector assembly 14 mounted on frame 16 of bicycle 12 immediately behind the seat 18 of the bicycle. A transmission including a ring gear 20 rotatable coaxially with a hub 22 and mounted on the spokes of the rear wheel 24 of bicycle 12 as by the illustrated radially slotted stiffener ring provided on the back of gear 20 for moving reflector assembly 14 as a function of an angular speed of wheel 24. A flex drive shaft 26 is illustrated in FIGS. 1 and 2 as attached to assembly 14 and ring gear 20 for operably connecting gear 20 to assembly 14. Referring now more particularly to FIGS. 3 and 4 of the drawings, reflector assembly 14 includes a base 28 having attached thereto a bracket 30 for mounting base 28 on frame 16 of bicycle 12. A reflector arrangement 32 is rotatably mounted on base 28 as by means of a motion converter 34 also mounted on base 28 and connected to drive shaft 26 and reflector arrangement 32 for imparting an irregular motion to reflector arrangement 32. A transparent enclosure 36 is mounted on base 28, and houses a hollow prism 38 having a pair of substantially parallel end faces 40 and 42 and at least three side faces 44. As illustrated, prism 38 is provided with six side faces 44. Prism 38 is supported by the motion converter 34 for movement therewith, and is journaled at the upper portion thereof, or adjacent face 40 to enclosure 36. More specifically, a projection 46 is provided at the uppermost portion of enclosure 36 which is received in a recess provided in a cup 48 formed on the upper surface of face 40. Preferably, the side faces 44 are constructed from a suitable, known reflective material, with each side face 40 being provided with a different color in order to enhance the flashing effect of reflector arrangement 32, which flashing effect is obtained by means of the motion converter 34. In the embodiment of the invention shown in FIGS. 1 through 4 of the drawings, motion converter 34 is in the form of a Geneva mechanism 50, which can be seen in FIG. 5. Mechanism 50 is arranged for imparting intermittent, continuous direction, motion to the reflector arrangement 32, and includes an actuating wheel 52 to which motion is imparted from a pinion 54 affixed to one free end of a line 56 (FIG. 3) which partially forms the flexible drive shaft 26. A sleeve 58 is arranged protectively surrounding the line 56 and extending from a fitting 60 disposed adjacent pinion 54 to a fitting 62 disposed adjacent the ring gear 20. Wheel 52 is provided with a gear 64 which meshes with pinion 54, and with a hub 66 disposed on a face of wheel 52 opposite to the face to which gear 64 is affixed and provided with an arcuate cutout 68 for permitting the step-by-step motion of mechanism 50 in a manner well known. A pin 70 is also provided on the surface of wheel 52 to which hub 66 is affixed, and this pin 70 intermittently engages in the slots 72 of a wheel 74 rotatably mounted on base 28. As can be seen from FIG. 3, a shaft 76 rotatably mounts wheel 52 on base 28, while a shaft 78, like shaft 76 received in an appropriate socket provided in base 28, rotatably mounts wheel 74. Since the operation of a Geneva mechanism such as that designated 50 is well known and commonly employed where intermittent uni-directional motion is desired, the operation of mechanism 50 will not be described in detail herein. Referring now to FIG. 6 in conjunction with FIG. 3, it can be seen that a pinion 80 is mounted to the end of line 56 which is disposed adjacent the ring gear 20. A suitable coupling 82 secures line 56 to pinion 80 and the fitting 62 so that the teeth of pinion 80 can engage in the apertures 84 formed in ring gear 20 so that rotary movement of gear 20, which of course will be a function of rotation of wheel 24, will cause rotation of pinion 80, line 56, and pinion 54 in order to actuate the mechanism 50 and impart intermittent motion to the reflector arrangement 32, the end face 42 of which is affixed to wheel 74 of mechanism 50 in a suitable, known manner. FIG. 7 of the drawings shows a modified embodiment of the present invention, inasmuch as the Geneva mechanism 50 is replaced by a crank and rocker four link mechanism 86 which will impart oscillating motion to the reflector arrangement 32. The crank of mechanism 86 is in the form of a wheel 88 connected to the ring gear 20 in a suitable manner, such as by the line 56 of a flexible drive shaft. The rocker is also in the form of a wheel 90 to which reflector arrangement 32 is affixed. By pivotally connecting the spaced ends of a connecting rod 92 to the wheels 88 and 90, mechanism 86 is formed in such a manner that rotation of wheel 88 will cause oscillating motion of wheel 90 about a shaft 78 in a known manner. It will be appreciated that when the crank and rocker four link mechanism 86 of FIG. 7 is employed, the reflector arrangement is still advantageously constructed in the manner of arrangement 32, since even the oscillating motion imparted to the reflector arrangement by mechanism 86 will result in the side faces 44 being exposed to view from the sides and rear of a bicycle 12, or other suitable vehicle, during an oscillating cycle of the reflector arrangement. Referring now more particularly to FIGS. 8 and 9 of the drawings, an embodiment of the invention is shown wherein the reflector assembly 14 is mounted immediately adjacent the hub 22 of a bicycle wheel so as to directly engage ring gear 20 as by a pinion 94 rigidly connected to reflector assembly 14 by a shaft assembly 96. In this embodiment of the invention, reflector assembly 14 is mounted on frame 16 of the bicycle at the, for example, rear wheel hub area thereof as by a suitable bracket 98 which is dissimilar from bracket 30, but is somewhat similar to the bracket 100 (FIG. 1) which is preferably provided with the embodiment shown in FIGS. 1 through 4 in order to assure that the flexible drive shaft 26 retains its proper position adjacent the hub 22, and does not flop into the, for example, spokes of the wheel 24. A bracket 102 (FIG. 1) may also be provided in conjunction with drive shaft 26 for securing same relative to frame 16 and wheel 24. As will be appreciated, the various embodiments of the invention described above are all formed around a basic reflector assembly 14 and transmission device such as formed by ring gear 20. Accordingly, a reflector 10 according to the present invention provides a versatile device for a bicycle or similar vehicle which can be mounted as appropriate to provide an easily identifiable reflector in a simple yet rugged and reliable manner. For example, if an infant seat (not shown) is mounted behind the bicycle seat 18, the flexible drive shaft 26 can be appropriately moved to the back side of the infant seat by directing flexible shaft 26 accordingly. This would require only movement of the securing bracket 102, for example. The side faces 44 of the reflector assembly may be constructed from suitable synthetic materials, and the like, commonly employed as reflectors, and may be of any suitable color such as red, amber, and the like, or from a combination of such colors. The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
A rotatable multi-surface reflector for bicycles has a reflector assembly mounted on a bicycle and connected to a transmission which moves the reflector assembly as a function of the angular speed of a wheel on which the transmission is mounted. The reflector assembly includes a mechanism connected to the transmission for converting the circular motion received from the transmission into an irregular motion so as to cause the reflector assembly to provide a flashing effect when light is impinging on reflection surfaces provided in the reflector assembly.
1
FIELD OF THE INVENTION A hollow monument structure consisting essentially of ceramic material. BACKGROUND OF THE INVENTION Grave monuments are well known to those skilled in the art. Thus, by way of illustration and not limitation, reference may be had to design U.S. Pat. No. 259,369 of Splendora (which discloses a transparent monument containing a decorative object within it), design U.S. Pat. No. 310,419 of Morvant (which discloses a permanent photographic memorial marker), and U.S. Pat. No. 3,938,286 of Mochinski (a grave marker comprised of a lucite block), 3,962,836 of Carnes et al. (a grave marker with a transparent cover), 4,058,940 of McBrayer (a monument marker comprised of a clear plastic outer laminate), 4,202,144 of Patterson (a cemetery monument), 4,227,325 of Whitford (a grave marker comprised of a cylindrical chamber within which is mounted a picture), 4,259,381 of Narita (an ornament for burial monuments which contains a transparent body), 4,304,076 of Splendora (a transparent monument), 4,337,109 of Narita ( a process for preparing a burial ornament), 4,428,168 and 4,428,169 of Tomer (a permanent floral decoration for use on grave sites), 4,550,537 of Smith (a grave monument), and the like. The disclosure of each of these United States patents is hereby incorporated by reference into this patent application. Many of the prior art monuments are solid devices made out of granite. They are heavy, expensive, and require a substantial amount of labor to construct and move. Furthermore, the granite monuments will often support the growth of vegetation (such as lichen, moss, and the like) and be subject to attack by acid rain. Despite the substantial costs of such monuments, they often within a period of about twenty years cease to serve their intended functions of indicating information about the individuals buried beneath them. It is an object of this invention to provide a monument which is substantially less expensive to produce and easier to manipulate than prior art granite monuments. It is another object of this invention to provide a monument which will not support the growth of vegetation as readily as do granite monuments. It is yet another object of this invention to provide a monument which is less subject to attack to acid rain than are granite monuments. These and other objects of the invention will be apparent upon a reading of this specification. SUMMARY OF THE INVENTION In accordance with this invention, there is provided a monument structure comprised of a monument attached to base. The base and monument are constructed from relatively thin walls of ceramic material. Orifices communicate between the monument and the base and allow the flow of water therebetween. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be more fully understood by reference to the following detailed description thereof, when read in conjunction with the attached drawings, wherein like reference numerals refer to like elements, and wherein: FIG. 1 is a perspective view of one preferred embodiment of the monument structure of the invention; FIG. 2 is a top view of the monument depicted in FIG. 1; FIG. 3 is a front view of the monument structure of FIG. 1; FIG. 4 is a side view of the monument structure of FIG. 1; FIG. 5 is a sectional view of the monument structure of FIG. 1; FIG. 6 is a partial sectional view illustrating one preferred means of attaching the monument to the base; FIG. 7 is a perspective view of a flag holder which may be used on the structure of FIG. 1; FIG. 8 is a side view of the flag holder of FIG. 7; FIG. 9 is a sectional view of a plug used in the monument of FIG. 1; FIG. 10 is a sectional view of eye bolt used with the monument of FIG. 1; FIG. 11 illustrates one preferred means of removing the monument of FIG. 1 from the base of FIG. 1; FIG. 12 is an exploded view of the monument of FIG. 1. DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view of the monument structure 10 of this invention. Referring to FIG. 10, it will be seen that monument structure 10 is comprised of monument 12 and base 14. Each of monument 12 and base 14 is preferably an integral structure comprised of relatively thin walls. Thus, referring to FIG. 1, it will be seen that base wall is comprised of front wall 16, right wall 18, left wall 20, back wall 22, and bottom wall (not shown in FIG. 1, but see bottom wall 24 of FIG. 5). It is preferred that each of the walls of monument 12 and base 14 be at least about 0.5 inches thick. In one preferred embodiment, each of such walls is from about 0.5 to about 1.0 inches thick. In an even more preferred embodiment, each of such walls is from about 0.5 to about 0.8 inches. Each of the walls of monument 12 and base 14 preferably comprise at least about 90 weight percent of ceramic material and, more preferably, at least about 95 weight percent of ceramic material. In one preferred embodiment, reinforcing rods (such as those made from fiberglass) may be used to strengthen the walls of the monument and/or base. The term ceramic, as used in this specification, refers to a class of inorganic, nonmetallic products which are subjected to a temperature of 540 degrees or more during manufacture or use, and it includes metallic oxides, borides, carbides, or nitrides, and mixtures or compounds of such material. In one preferred embodiment, the ceramic material used is terra cotta. As is known to those skilled in the art, terra cotta is an unglazed, low-fired ornamental earthenware material. Thus, one may use one or more of the terra cotta materials disclosed in U.S. Pat. Nos. 5,247,762 (terra cotta reservoir), 5,189,835 (terra cotta reservoir), 4,255,200, and the like. The disclosure of each of these United States patents is hereby incorporated by reference into this specification. In another preferred embodiment, the ceramic material used is a stoneware clay composition. As is known to those skilled in the art, stoneware clay is a semirefractory plastic clay which will fire to a dense, vitrified body of high strength; see, e.g., A.S.T.M. C242. One may use one or more of the stoneware compositions described in the prior art such as, e.g., those described in U.S. Pat. Nos. 5,352,396, 5,315,922, 5,275,989 (stoneware composition), 4,542,058, 4,119,470 (stoneware composition), 3,487,140, and the like. The disclosure of each of these United States patents is hereby incorporated by reference into this specification. By way of further illustration, the monument 12 and/or base 14 may be made by casting liquid clay, or terra cotta clay, into plaster molds. The casting of green bodies using clay or clay-containing compositions is well-known to those skilled in the art and is described, e.g., in U.S. Pat. Nos. 5,372,179 (casting mold), 5,362,692 (casting slip), 5,356,575, 5,340,107, 5,266,252, 5,156,855 (slip casting), 5,153,155 (clay slurry), 5,143,871, 4,659,749 (casting mixture), 3,7000,472, and the like. The disclosure of each of these United States patents is hereby incorporated by reference into this specification. In one preferred embodiment, plastic clay is used to prepare the monument 12 and/or base 14. As is known to those skilled in the art, plastic lay is any clay which will form a moldable mass when blended with water. See, e.g., U.S. Pat. Nos. 4,857,256 and 4,786,457, the disclosures of which are hereby incorporated by reference into this specification. In one preferred embodiment, the monument 12 and the base 14 are made by forming green bodies by casting a clay composition, or a terra cotta composition, into plaster molds. The green bodies thus produced are finished and dried and fired. In one preferred embodiment, the exterior walls of monument 12 and base 14 are glazed by conventional processes and thereafter fired. Thus, one may use one or more of the glaze compositions and/or glaze processes disclosed in U.S. Pat. Nos. 5,370,783 (ceramic glaze), 5,366,763 (vitreous glaze), 5,362,687 (lead-free frit glaze), 5,300,324, 5,256,179, 5,238,881 (glass frit glaze), 5,194,296 (glaze slip), 4,839,313, 4,790,110, 4,308,183, 4,276,204, and the like. The disclosure of each of these United States patents is hereby incorporated by reference into this specification. Referring again to FIG. 1, it will be seen that, in the preferred embodiment illustrated, monument 12 has a substantially rectilinear shape. However, it will be apparent to those skilled in the art that, in the monument structure of this invention, other monument shapes may be used. As is known to those skilled in the art, a monument is an inscribed stone or other marker erected as a memorial. Monuments are well known to those skilled in the art. Thus, e.g., reference may be had to U.S. Pat. No. 3,938,286, which discloses an integral body having a generally upright member with a top and bottom and having a decorative exterior bearing identifying indicia. Thus, e.g., reference may be had to U.S. Pat. Nos. 3,962,836, 945,721, and 2,046,594. Thus, e.g., reference also may also be had to U.S. Pat. Nos. 4,058,940 and 2,124,143, U.S. Pat. No. 4,169,970 (which discloses tombstones and memorial monuments), U.S. Pat. No. 4,202,144, U.S. Pat. No. 4,227,325 (which discloses a grave marker having a base, a marker, and a chamber for displaying pictures, photographs and the like), U.S. Pat. No. 4,304,076, U.S. Pat. No. 4,550,537, and U.S. Pat. Nos. 4,202,144, 4,009,547 (monument base), D243,466, 5,014,472, 3,857,214 (method of making tombstones), 3,481,089 (memorial marker with removable indicia), 3,477,181 (tombstone frames), and the like. The disclosure of each of these United States patents is hereby incorporated by reference into this specification. Referring again to FIG. 1, and in the preferred embodiment depicted therein, it will be seen that the top 22 of monument 12 is comprised of a first plug 24 and a second plug 26. These plugs are shown in greater detail in FIGS. 9, 10, and 11. Referring to FIG. 9, and in the preferred embodiment depicted therein, it will be seen that plug 24 is removably disposed within an orifice in top wall 22 of monument 12. In the embodiment depicted, the plug 24 is screwably connected to a flange 28, which fits within said orifice and is contiguous with the bottom surface 30 of top wall 22 of monument 12. When force is applied in the direction of arrow 32 on plug 24, the flange 28 tends to keep plug 24 disposed within wall 22. Referring to FIG. 6, plug 24 may be removed from wall 22, thereafter liquid 32 may be added to the interior 34 of monument 12 by pouring said liquid 32 in the direction of arrows 36, and, after a suitable amount of such liquid 32 has been added, the plug 24 may be reinstalled. Referring to FIG. 10, the plug 24, and/or the plug 26, may be replaced with an eye bolt 38, which may be secured within wall 22 in the same manner as plugs 24 and/or 26. As is illustrated in FIG. 11, when two such eye bolts (eye bolt 38 and eye bolt 40) are so installed, the monument 12 may be separated from the base 14 by exerting force in the direction of arrow 42 by conventional means such as, e.g., hook and tackle 44. Referring again to FIG. 1, and in the preferred embodiment depicted therein, it will be seen that the front face 48 of monument 12 is comprised of recesses 50 and 52 (which may, e.g., be about groove adapted to receive a plate) adapted to receive one or more plates with indicia or inscriptions or designs or colors on them. Thus, referring to FIG. 12, two such plates 54 and 56 are shown. In the embodiment depicted, they may be removed from recess 52 by applying force in the direction of arrows 58 and may be reinserted by applying force in the opposite direction. In another embodiment, the plates 54 and 56 are permanently affixed within groove 52 by suitable means such as, e.g., adhesive. Referring again to FIG. 1, it will be seen that attached to monument 12 is flag holder 60 in which United States flag 62 is preferably disposed. One may insert flags of other entities to whom one owes allegiance, such as the Buffalo Bills. One may use any of the flag holders known to those skilled in the art such as, e.g., one or more of the flag holders described in U.S. Pat. Nos. 5,309,862, 5,236,166, 5,197,408, 5,087,012, 5,028,031, 3,952,981, 3,941,340, 3,903,835, 3,825,214, 3,722,841, D342,895 (lighted flag holder), and the like. The disclosure of each of these United States patents is hereby incorporated by reference into this specification. FIG. 7 is a perspective view of one preferred flag holder 60 which is comprised of orifices 62 and 64 and recess 66, which is adapted to receive the bottom of the flag pole. Referring to FIGS. 2 and 3, base 14 and/or monument 12 may be connected to a concrete base by conventional means. Any conventional means for supporting monument 12 and/or base 14 may be used. Thus, by way of illustration and not limitation, one may use one or more of the concrete anchor arrangements well known to those skilled in the art. For example, one may use the devices illustrated in U.S. Pat. Nos. 5,107,650 (concrete anchors), 5,074,095, 5,063,724 (anchor for fixing a rod in concrete), 5,049,015, 4,872,298, and the like. The disclosure of each of these United States patent applications is hereby incorporated by reference into this specification. Thus, e.g., the base 14 can be mounted on a concrete foundation which is disposed within ground 68 (see FIG. 5) This mounting means is well known to those skilled in the art. Thus, e.g., one may dig a suitable hole in the ground 68, and pour concrete within such hole and allow it to harden so that it fills all of such hole except for recesses; thereafter steel anchors may be attached. In the embodiment illustrated in FIG. 5, a recess is dug into ground 68 and filled with concrete 70. Lag screw receptacles 72 and 74 may be disposed within the concrete 70 (preferably when the concrete 70 is still fluid), and lag screws 76 and 78 then may be used to secure base 14 and/or monument 12 to the concrete 70. Referring again to FIG. 1, and in the preferred embodiment depicted therein, it will be seen that base 14 defines a substantially rectangular container into which earth 68 may be charged. Flowers and/or other plants 80 (such as ivy) may then be planted within base 14. Water from the interior of monument 12 may then be used to nourish such plants. Referring again to FIG. 5, it will be seen that, in the embodiment depicted, the base 12 is comprised of weep hole 84 which allows water from reservoir 88 in monument 12 to passes in the direction of arrow 90 and to water earth 68. When, however, one wishes to remove water from the reservoir 88 (such as, e.g., when winter is approaching), plug 92 may be moved in the direction of arrow 94 to allow water to escape therefrom and thereafter may be reinstalled. FIGS. 7 and 8 illustrate one preferred means of connecting monument 12 to base 14, by means of a tongue 94/groove 96 arrangement. The tongues 94 (see FIGS. 5) may be set within grooves 96 of base 14 and retained there by the force of gravity and by friction fit. Alternatively, or additionally, the tongues 94 may also be adhesively joined within grooves 96 by, e.g., suitable glue. The advantages of applicant's novel monument structure are readily apparent. In the first place, because of its ceramic composition, it can be repaired more readily than can prior art monuments. In the second place, it can display more information (such as dates, times, achievements, colors, etc.) than can comparable prior art monuments; thus, e.g., a brass Veterans plaque can readily be secured to its back surface. It is to be understood that the aforementioned description is illustrative only and that changes can be made in the apparatus, in the ingredients and their proportions, and in the sequence of combinations and process steps, as well as in other aspects of the invention discussed herein, without departing from the scope of the invention as defined in the following claims.
A monument assembly contaiing a monument attached to a base. The base is in the shape of an open container, and its walls (and the walls of the monument) are each from about 0.5 to about 1.0 inches thick and are comprised of at least about 90 weight percent of ceramic material. The monument is an integral assembly containing an interior chamber; it contains a device for charging water to the interior chamber, a device for removing water from the interior chamber, and at least one device for for removably attaching the monument to the base.
4
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to light emitting devices and more particularly to light emitting devices having luminescent layers comprising piezoelectric material. 2. Description of the Related Art Piezoelectric thin-films have been widely used in vibrators, such as piezoelectric resonators and piezoelectric actuators, and driving devices. In recent years, piezoelectric thin-films also have attracted attention as optical devices. For example, Japanese Unexamined Patent Application Publication No. 7-262801 discloses a light emitting device which has a ZnO film formed on a sapphire substrate and emits ultraviolet light by the effects of excitons. Moreover, Japanese Unexamined Patent Application Publication No. 10-256673 discloses a light emitting device which emits ultraviolet light by laser oscillation. Properties of piezoelectric films, however, have not been sufficiently known. In particular, properties of piezoelectric films suitable for light emitting devices and methods for making the piezoelectric films have not yet been sufficiently studied. Thus, piezoelectric films used in conventional light emitting devices do not have high luminous efficiency. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a light emitting device having high luminous efficiency and high luminous intensity. The light emitting device comprises: a substrate; and a first piezoelectric film held on the substrate and having one of a positive plane and a negative plane, the first piezoelectric film functioning as a light emitting layer. According to another aspect of the present invention, a method for making a light emitting device comprises the steps of: preparing a substrate; and forming a first piezoelectric film having one of a positive (+) upper plane and negative (−) upper plane on the substrate, according to properties of the substrate. When the first piezoelectric film has the positive plane, it is preferable that the substrate is selected from the group consisting of a c-plane sapphire substrate, an R-plane sapphire substrate, an m-plane sapphire substrate, an X-plane sapphire substrate, an a-plane sapphire substrate, a rotated Y-cut plate sapphire substrate, a double rotated sapphire substrate, a rotated Y-cut plate quartz substrate, a Z-plane quartz substrate, a LiTaO 3 substrate having a negative Z plane of a rotated Y-cut plate, and a LiNbO 3 substrate having a negative Z plane of a rotated Y-cut plate. When the first piezoelectric film has the negative plane, it is preferable that the substrate is selected from the group consisting of a LiNbO 3 substrate having a positive Z plane of a rotated Y-cut plate LiNbO 3 substrate, a LiTaO 3 substrate having a positive Z plane of a rotated Y-cut plate LiTaO 3 substrate, a LiTaO 3 substrate having a positive Z plane, a LiNbO 3 substrate having a positive Z plane, a glass substrate, A Si substrate, a metal substrate, and a substrate having a metal film thereon. The first piezoelectric film preferably comprises a material selected from ZnO, AlN, and CdS. The light emitting device may further comprises a second piezoelectric film, the first piezoelectric film and the second piezoelectric film having different conductivity types. In the light emitting device, the substrate may have a plurality of metal film stripes thereon, the first piezoelectric film covers the metal film stripes, and the first piezoelectric film has the negative plane. According to the present invention, a piezoelectric film having a positive plane or a negative plane is selectively provided depending on the type of the substrate, and the piezoelectric film has high crystallinity. Thus, the resulting light emitting device has high brightness and high luminescent efficiency. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view of a light emitting device in accordance with a first embodiment of the present invention; FIG. 2 is a luminescence spectrum of a ZnO thin-film having a positive plane, formed on a c-plane sapphire substrate; FIG. 3 is a luminescence spectrum of a ZnO thin-film having a positive plane, formed on a Z-plane quartz substrate; FIG. 4 is a graph of the luminous intensity of a ZnO thin-film having a positive plane on a c-plane sapphire substrate and that of a ZnO thin-film having a negative plane on a c-plane sapphire substrate; FIG. 5 is a graph showing the X-ray diffraction intensity of ZnO thin-films having positive planes formed on c-plane sapphire substrates; FIG. 6 is a graph showing the X-ray diffraction intensity of ZnO thin-films having positive planes formed on negative Z plane LiNbO 3 substrates; FIG. 7 is a schematic cross-sectional view of a light emitting device in accordance with a second embodiment of the present invention; FIG. 8 is a schematic cross-sectional view of a light emitting device in accordance with a third embodiment of the present invention; and FIG. 9 is a schematic cross-sectional view of a light emitting device in accordance with a fourth embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS The inventor of the present invention found useful facts based on the relationships between physical properties of the piezoelectric film used in the light emitting device and the orientation thereof, and between the substrate type and the orientation of the piezoelectric film suitable for the substrate. When the orientation direction of the piezoelectric film is appropriately selected based on the substrate type, the crystallinity of the piezoelectric film is improved, and the light emitting device exhibits satisfactory properties. These relationships were not previously clear, and the attention to the relationships is itself unique. The positive plane and the negative plane in the present invention represent the orientation direction of the piezoelectric film and indicate the sign of charge occurring on the main outer surface of the thin film. That is, the positive plane indicates a plane which is positively charged due to the tension caused at load the piezoelectric film, whereas the negative plane indicates a plane which is negatively charged due to tension caused at the piezoelectric film. In the case where the piezoelectric film is a ZnO, AlN or CdS film, it is thought that the positive plane there of has a Zn, Al or Cd layer at the very surface of the positive plane, and that the negative plane thereof has a O, N or Cd at the very surface of the negative plane. More specifically, when a piezoelectric film is formed on a piezoelectric substrate having a negative plane such as c-plane sapphire substrate, an R-plane sapphire substrate, an m-plane sapphire substrate, an a-plane sapphire substrate, a rotated Y-cut plate sapphire substrate, a double rotated Y-cut plate sapphire substrate, a rotated Y-cut plate quartz substrate, a Z-plane quartz substrate, a LiTaO 3 substrate having a negative Z plane, or a LiNbO 3 substrate having a negative Z plane, a ZnO film is formed on the substrate so that the outer surface of the piezoelectric film is a positive plane (the inner surface in contact with the substrate is a negative plane). No polarization treatment of the LiTaO 3 substrate is required. The negative Z plane indicates a plane, which is negatively charged due to tension of planes in the Z-axis direction (Z planes). It is to be noted that, as long as the plane is charged uniformly with a negative charge, the plane may be slightly deviated from in the Z-axis direction. Alternatively, when a piezoelectric film is formed on a piezoelectric substrate having a positive plane such as a LiNbO 3 substrate having a positive Z plane of a rotated Y-cut plate LiNbO 3 substrate, a LiTaO 3 substrate having a positive Z plane of a rotated Y-cut plate LiTaO 3 , a LiNbO 3 substrate having a positive Z plane, and a LiTaO 3 substrate having a positive Z plane, a glass substrate or a Si substrate, a metal substrate, or a substrate having a metal film thereon, a ZnO film is formed on the substrate so that the outer surface of the piezoelectric film is a negative plane (the inner surface in contact with the substrate is a positive plane). Preferably, the first piezoelectric film on the substrate comprises a material selected from ZnO, AlN, and CdS. In devices which emit ultraviolet light, the piezoelectric film preferably comprises ZnO. The charging characteristics of the piezoelectric film on the substrate are determined by the method for making the piezoelectric film, fabrication conditions, and surface treatment of the substrate. For example, when the piezoelectric film is formed in an ECR system, such as an ECR plasma enhanced CVD system or an ECR sputtering system, an increased microwave power (e.g., more than 300 W) or an elevated heating temperature (e.g., more than 500° C.) readily forms a positive plane. In particular, a piezoelectric film formed on a substrate and heated at a temperature of 1,000° C. or more for several hours in a N 2 , O 2 , H 2 O or air atmosphere has a satisfactory positive plane. Also, the substrate bias voltage controls the polarity (the formation of the positive plane or the negative plane). In a sputtering system, the polarity of the piezoelectric film can be readily controlled by adjusting the gas composition in the deposition system, the heating temperature of the substrate and the bias voltage applied to the substrate. In particular, a bias voltage in a range of −500 V to +500 V is effective for controlling the polarity. By forming a piezoelectric film having a positive plane or a negative plane depending on the type of the substrate, the resulting light emitting device exhibits high luminous intensity. FIG. 1 is a schematic cross-sectional view of a light emitting device 11 in accordance with a first embodiment of the present invention. The light emitting device 11 includes a substrate 1 and a ZnO thin-film 2 formed thereon. When the substrate 1 is a c-plane sapphire substrate, an R-plane sapphire substrate, an m-plane sapphire substrate, an a-plane sapphire substrate, a rotated Y-cut plate sapphire substrate, a double rotated sapphire substrate, a rotated Y-cut plate quartz substrate, a Z-plane quartz substrate, a LiTaO 3 substrate having a negative Z plane or a LiNbO 3 substrate having a negative Z plane, the ZnO thin-film 2 has a positive Z plane. On the other hand, when the substrate 1 is a LiNbO 3 substrate having a positive Z plane of a rotated Y-cut plate LiNbO 3 substrate, a LiTaO 3 substrate having a positive Z plane of a rotated Y-cut plate LiTaO 3 substrate, a LiTaO 3 substrate having a positive Z plane, a LiNbO 3 substrate having a positive Z plane, a glass substrate, a Si substrate, a metal substrate or a substrate having a metal film thereon, the ZnO thin-film 2 has a negative Z plane. The light emitting device 11 emits light by the effects of excitons or by recombination of electrons with holes. As shown in FIG. 1, when the ZnO thin-film 2 is irradiated with a He-Cd laser (as indicated at 4 ), the light emitting device 11 emits 370-nm light corresponding to the band gap of ZnO by photoluminescence. The following experimental results show that the above combinations provide piezoelectric films having high crystallinity. In the experiments, using c-plane sapphire substrate and a Z-plane quartz substrate, piezoelectric films were formed under various deposition conditions and in various substrate surface states, and the orientation of each ZnO thin-film was observed using a nonlinear dielectric microscope. Specifically, three samples were prepared in an ECR sputtering system under the following conditions. Condition 1 Microwave power: 100 W RF power: 300 W Substrate temperature: 200° C. Ar/O 2 partial pressure ratio: 70/30 Condition 2 Microwave power: 500 W RF power: 450 W Substrate temperature: 500° C. Ar/O 2 partial pressure ratio: 70/30 Condition 3 Microwave power: 300 W RF power: 400 W Substrate temperature: 450° C. Ar/O 2 partial pressure ratio: 70/30 Nonlinear dielectric micrographs of the piezoelectric films prepared under these conditions. The piezoelectric film prepared under Condition 1 was found to be neither a positive plane nor a negative plane on the whole. Under Condition 2, the film was a uniformly distributed positive plane and under Condition 3, the film was a uniformly distributed negative plane. Thus, the piezoelectric film can have a positive plane, a negative plane, or a nonpolar plane depending on the ECR sputtering conditions. Under conditions other than Conditions 2 and 3, the piezoelectric film having the negative plane can be readily formed by applying a positive bias voltage to the substrate, whereas the piezoelectric film having the positive plane can be readily formed by applying a positive bias voltage. Each light emitting device was irradiated with a He—Cd laser to measure photoluminescence. FIG. 2 is a luminescence spectrum in a range of 350 to 400 nm of the ZnO thin-film having the positive plane formed on the c-plane sapphire substrate. FIG. 3 is a luminescence spectrum in a range of 360 to 390 nm of the ZnO thin-film having the positive plane, formed on the Z-plane quartz substrate. The spectrum shown in FIG. 2 has an intense luminescence peak at 367.8 nm which corresponds to the excitons. The spectrum shown in FIG. 3 also has a peak at 368 nm. FIG. 4 shows the luminous intensity of the ZnO thin-film having the positive plane on the c-plane sapphire substrate and that of the ZnO thin-film having the negative plane on the c-plane sapphire substrate. The results indicate that the ZnO thin-film having the positive plane has a luminous intensity which is approximately five times the luminous intensity of the ZnO thin-film having the negative plane, and has a narrower half width. Thus, the ZnO thin-film having the positive plane formed on the c-plane sapphire substrate has superior properties. FIG. 5 is a graph showing the X-ray diffraction intensity of ZnO thin-films having positive planes formed on the c-plane sapphire substrates under different conditions. In FIG. 5, the abscissa indicates the partial pressure ratio of Ar to O 2 in a gaseous environment for forming the ZnO thin-films, while the ordinate indicates the X-ray diffraction intensity (relative value) of the ZnO thin-films. These values are measured at substrate temperatures in a range of 200° C. to 600° C. As shown in FIG. 5, the ZnO thin-film has the positive plane at an intensity exceeding 4×10 4 (arbitrary units) or has both a positive plane region and a negative plane region at an intensity of less than 4×10 3 . The ZnO thin-film may have the positive plane or negative plane in an intensity between 4×10 4 and 4×10 3 , showing uncontrolled film deposition. A similar tendency is observed when the ZnO thin-film is formed on the Z-plane quartz substrate. FIG. 6 shows the results when ZnO thin-films are formed on the negative Z plane LiNbO 3 substrates. In this case, the ZnO thin-film has the positive plane at an intensity exceeding 1.4×10 5 (arbitrary units) or has both a positive plane region and a negative plane region at an intensity of less than 9×10 3 . The ZnO thin-film may have the positive plane or negative plane in an intensity between 1.4×10 5 and 9×10 3 , showing uncontrolled film deposition. A similar tendency is observed when the ZnO thin-film is formed on the Z-plane quartz substrate. As shown in FIGS. 5 and 6, the partial pressure ratio of Ar to O 2 controls the orientation of the ZnO thin-film, and the ZnO thin-film has a satisfactory positive plane at a partial pressure ratio of 75/25 to 65/35. When the ZnO thin-film having the positive plane is formed on the c-plane sapphire substrate, the orientation of the ZnO thin-film is improved by heating the substrate to 500° C. or more. When the ZnO thin-film having the positive plane is formed on the LiNbO 3 substrate having the negative plane, the orientation of the ZnO thin-film is improved by heating the substrate to 300° C. or more. In addition to the ZnO thin-film, an AlN thin-film having a positive plane or a CdS thin film may be formed on a c-plane sapphire substrate, an R-plane sapphire substrate, an m-plane sapphire substrate, an a-plane sapphire substrate, a rotated Y-cut plate sapphire substrate, a double rotated sapphire substrate, a rotated Y-cut plate quartz substrate, a Z-plane quartz substrate, a LiTaO 3 substrate having a negative Z plane, or a LiNbO 3 substrate having a negative Z plane, in order to form a light emitting device having satisfactory luminescent properties. FIG. 7 is a schematic cross-sectional view of a light emitting device 21 in accordance with a second embodiment of the present invention. The light emitting device 21 includes a c-plane sapphire substrate 22 , a plurality of Al film stripes 23 which are formed with a predetermined interval on the c-plane sapphire substrate 22 , and a ZnO thin-film 24 which is formed on the c-plane sapphire substrate 22 so as to cover the Al film stripes 23 . That is, the ZnO thin-film 24 is composed of regions 24 b lying on the Al film stripes 23 and regions 24 a directly lying on the c-plane sapphire substrate 22 , and the regions 24 a and the regions 24 b are alternately arranged in the direction 25 . Each region 24 b has a negative plane, whereas each region 24 a has a positive plane. That is, the ZnO thin-film on the c-plane sapphire substrate 22 has a uniform positive plane, and the ZnO thin-film on the Al film stripes 23 has a negative plane. Other substrates suitable for forming the ZnO thin-film having the positive plane may be used instead of the c-plane sapphire substrate 22 . Examples of such substrates are the rotated Y-cut plate quartz substrate and the Z-plane quartz substrate. Since the c-plane sapphire substrate and the Al film stripes have different orientation characteristics with respect to the ZnO thin-film, the alternating arrangement of negative regions and positive regions is achieved under optimized deposition conditions. For example, a positive bias voltage and a negative bias voltage are applied to the Al film and the sapphire film, respectively. The light emitting device 21 functions as a second-harmonic generation (SHG) device. As shown in FIG. 10, when red light is incident on one side face of the ZnO thin-film 24 along the direction 25 , blue light is emitted from the other side face of the ZnO thin-film 24 . Thus, the present invention can provide a SHG device having satisfactory properties. FIG. 8 is a schematic cross-sectional view of a light emitting device 31 in accordance with a third embodiment of the present invention. The light emitting device 31 includes a c-plane sapphire substrate 32 , an n-type ZnO layer 33 formed on the c-plane sapphire substrate 32 , a ZnO active layer 38 , and a p-type ZnO layer 39 . The upper face of the n-type ZnO layer 33 is a positive plane. Also, the upper faces of the ZnO active layer 38 and the p-type ZnO layer 39 are positive planes. The ZnO active layer 38 and the p-type ZnO layer 39 constitute a light emitting section 34 . The n-type ZnO layer 33 is doped with a Group III element, such as aluminum, as a dopant, and exhibits low resistance. The p-type ZnO layer 39 is doped with a Group V element, such as P or As. Electrodes 35 and 36 are formed on the n-type ZnO layer 33 and the p-type ZnO layer 39 , respectively. A current flows via the electrodes 35 and 36 and excitons induce luminescence in the light emitting section 34 . Since the ZnO active layer 38 having the positive plane and the p-type ZnO layer 39 having the positive plane are formed on the n-type ZnO layer 33 having the positive plane, the light emitting section 34 has high crystallinity, and the light emitting device 31 exhibits high brightness and high luminous efficiency. The n-type ZnO layer 33 is provided on the c-plane sapphire substrate 32 in this embodiment. Alternatively, the positions of the n-type ZnO layer 33 and the p-type ZnO layer 39 may be exchanged to invert the conductivity type. That is, a p-type ZnO layer may be formed on the c-plane sapphire substrate 32 and an n-type ZnO layer may be formed on the ZnO active layer 38 . FIG. 9 is a schematic view of a light emitting device 41 in accordance with a fourth embodiment of the present invention. The light emitting device 41 is of an edge emitting type, such as a laser diode or an edge emitting type diode. The light emitting device 41 includes a sapphire substrate 42 , a low-resistance ZnO layer 43 formed on the sapphire substrate 42 , and a light emitting section 44 . The sapphire substrate 42 has a C-, R-, m-, or a-plane, or is a rotated Y-cut or double rotated plate sapphire substrate, and the low-resistance ZnO layer 43 has a positive plane as the upper surface. The light emitting section 44 includes a p-type ZnO layer 45 , a ZnO active layer 46 , and an n-type ZnO layer 47 . Each of these layers 45 to 47 has a positive plane as the upper face by the effect of the orientation of the low-resistance ZnO layer 43 . A SiO 2 film 48 having a slit thereon is provided on the light emitting section 44 , and an upper electrode 49 is provided on the SiO 2 film 48 to cover the slit. The light emitting section 44 is partly etched so as to partly expose the low-resistance ZnO layer 43 , and a lower electrode 50 is provided on the exposed low-resistance ZnO layer 43 . When a current flows in the light emitting device 41 via the upper electrode 49 and the lower electrode 50 , blue to violet light is emitted from a side face by exciton luminescence. Since each of the layers 46 to 47 of the light emitting section 44 has the positive plane, the light emitting section 44 has high crystallinity and the light emitting device 41 has high brightness and high luminescent efficiency.
The light emitting device comprises: a substrate; and a first piezoelectric film held on the substrate and having one of a positive plane and a negative plane, the first piezoelectric film functioning as a light emitting layer.
7
SUMMARY OF THE INVENTION An object of our invention is to save the installation charge made by a plumber who would normally have to connect the city water supply line to the part of the refrigerator that supplys water to the automatic ice maker and to the ice water dispenser. Also, another advantage is that with our refrigerator water reservoir assembly, when applied to the refrigerator, it does away with the necessity of placing the refrigerator near to a water pipe that carries city water at a predetermined water pressure. The refrigerator can be placed anywhere desired. No changes in the refrigerator need be made when applying our device to it. A further object of our invention is to provide a device of the type described which is simple in construction and makes use of a single manually operated valve that can be swung into "REFILL" position for adding water to the reservoir and then can be swung into automatic or normal position where the device will automatically feed water at the proper pressure to either the ice maker or the ice water dispenser when it is needed. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of a standard refrigerator that has an automatic ice maker and an ice water dispenser. Our device is mounted on the top of the refrigerator and has a water conveying conduit extending from the reservoir to the standard water inlet to the two solenoid valves, one of the valves controlling the flow of water to the automatic ice maker and the other valve feeding water to the ice water dispenser when needed. FIG. 2 is an enlarged top plan view of the motor and pump and shows the connections between the pump and the multiple valve. This Figure further shows the adjacent portion of the water reservoir with the cover for the reservoir removed. FIG. 1 illustrates the cover lifted and the section line 2--2 in this Figure indicates the portion of the reservoir and operative mechanism being shown in FIG. 2. FIG. 3 is a vertical transverse section taken along the line 3--3 of FIG. 2 and shows the multiple valve housing and motor in elevation. FIG. 4 is a horizontal section taken along the line 4--4 of FIG. 3 and shows the valve housing in section but the valve body is not shown in section. FIG. 5 is an enlarged horizontal section through the valve body and is taken along the section line 5--5 of FIG. 3. The valve body has been moved into REFILL position for replenishing the reservoir with water. FIG. 6 is a horizontal section through the valve body and is similar to FIG. 5 excepting that the valve body is now in automatic or normal position where water will be automatically transferred from the reservoir to the automatic ice maker or to the ice water dispenser as needed. FIG. 7 is a vertical transverse section through the valve body and is taken along the line 7--7 of FIG. 5. DESCRIPTION OF THE PREFERRED EMBODIMENT In carrying out our invention we make use of a standard refrigerator indicated generally at A in FIG. 1, and has a standard automatic ice maker, shown by dotted lines at B, and a standard ice water dispenser shown at C. Our device includes a reservoir D that is preferably placed on top of the refrigerator and is large enough in capacity to hold about six gallons of water. A water gage 1 is applied to the front wall of the reservoir and will indicate the level of water in the reservoir. If desired, the water gage may have its tube calibrated for indicating the actual volume of water in the reservoir. A cover 2 normally closes the top of the reservoir but we have shown the cover lifted above the top of the reservoir so that the compartment 3 disposed at the rear of the reservoir can be viewed. We will first describe what is mounted in the compartment 3 and then will mention the water conveying conduits that lead from the multiple valve in the compartment to the auxiliary water supply E and to the water inlet 4 at the back of the refrigerator that connects with the two standard solenoid valves F and G already provided in the refrigerator, see FIG. 1. An enlarged top view of the compartment 3 at the rear of the reservoir D is shown in FIG. 2 and a front view of the compartment with the front wall removed is shown in FIG. 3. The multiple valve is indicated generally at H in both of these Figures and it consists of a housing H1 and a slidable valve body H2. Directly in back of the multiple valve H there is a water pump J, see FIG. 4, and mounted on top of the pump is an electric motor K, see FIGS. 2 and 3, that is operatively connected to the pump. In FIG. 4 the housing H1 of the multiple valve H is shown in horizontal section while the valve body H2 is shown in elevation. The pump J has a rotor 5 that rotates in a counter clockwise direction. An inlet pipe 6 for the pump J communicates with the valve housing H1 and with an L-shaped passage 7 in the valve body H2 when the valve body is in REFILL position. Both FIGS. 4 and 5 illustrate the valve body H2 in REFILL position which means that water will be withdrawn from the auxiliary source of water as shown by the five gallon jug of water E and delivered to the reservoir D for replenishing it. The transverse sectional view in FIG. 7 illustrates the L-shaped passage 7 in the valve body H2 in communication with the pump inlet pipe 6 and with a conduit 8 that leads to the auxiliary water source E, see also FIGS. 1, 2 and 3. The pump J draws water from the auxiliary source E through the conduit 8, the passage 7 in the valve body H2, the pipe 6 to the pump. From here the water is forced through the pump outlet pipe 9 to the valve housing H1 where the pipe communicates with a horizontal passage 10 in the valve body H2 when the valve body is in REFILL position, see FIG. 5. The water flows through the valve body passage 10 and then through a stub pipe 11 that extends from the valve housing H1 and into the reservoir D. A separate switch, not shown, may be used for connecting the motor K to a source of current when the valve body H2 is in REFILL position. The longitudinal movement of the valve body into REFILL position could cause the end of the extension 12 on the valve body to close an electric switch, now shown, for activating the motor and self-priming pump and then the switch would automatically open when the valve body H2 was moved into automatic or normal position. In FIGS. 1, 2, 3, 4, 5 and 6 we show one mechanism for moving the valve body H2 in a longitudinal direction between REFILL and AUTO (standing for the word automatic) position. A valve body actuator L includes a rod 13 that underlies the bottom of the reservoir D, see FIG. 2, and extends beyond the front wall 14 of the reservoir with the front portion being bent at right angles to the rod to constitute a handle 15, see FIG. 1. The rod 13 is mounted in bearings, not shown, so that the rod will rotate on its longitudinal axis when the handle 15 is swung from REFILL position to AUTO position and vice versa. The rear end of the rod 13 is formed into a crank 16 whose end is slidably received in an elongated vertical slot 17 in the valve body extension 12, see FIG. 3. The valve body actuator L is shown in REFILL position in FIGS. 1 to 5 inclusive. The operator watches the gage 1 at the front of the reservoir D and when the water level in the gage reaches a predetermined point he actuates the handle 15 and swings it to the AUTO position. This will move the valve body H2 in the direction of its length to the left from the REFILL position shown in FIGS. 2 to 5 inclusive into the AUTO position shown in FIG. 6. The AUTO position of the handle 15 is the normal position for our device to feed water automatically to the ice maker or to the ice water dispenser as needed. When the handle 15 is moved into AUTO position the conduit 8 is removed from the auxiliary water E and if the source is the five gallon jug it can be put away until again needed. The conduit 8 can be coiled and placed in an out of the way position. The standard refrigerator shown in FIG. 1 is equipped with the ice maker B and with the ice dispenser C. The refrigerator also has the two solenoid valves F and G and with the water inlet 4 that is usually connected to the city water supply line and this requires a plumber to make such a connection. Our device has a conduit 18, see FIGS. 1, 2 and 3, that leads from the multiple valve H and connects with the water inlet 4 in the refrigerator for supplying water to both solenoid valves F and G. We will now describe the apparatus for feeding water to the ice maker when needed. FIG. 6 illustrates the position of the valve body H2 when the handle 15 has been swung into AUTO position. A water pressure sensitive switch indicated generally at M in FIGS. 2 and 3, has a conduit 19 leading from it and communicating with the water outlet pipe 9 from the water pump J, see FIGS. 2, 3 and 4. The pressure sensitive switch is set to automatically close an electric circuit to the motor K when the water pressure in the pipe 9 drops below a predetermined point. The pressure sensitive switch M is set to maintain a pressure in the pipe 9 at between ten to twenty pounds. It will be seen that in FIG. 6, when the valve body H2 has been moved into AUTO position, the pipe 9 from the water pump J, see also FIG. 4, is in communication with an L-shaped passage 20 in the valve body that in turn communicates with the conduit 18 that leads to the water inlet 4 for both the solenoid valves F and G. FIG. 1 shows a conduit 21 leading from the ice maker B to the solenoid valve F. The time fill sequence in an ice maker is eight ounces of water in a time period of about eleven seconds. In order to attain this rapid water flow, pressuring of the water is necessary because of the restrictors in the refrigerator that restrain normal city water pressure. In normal operation of the refrigerator A, when the ice maker B in the refrigerator operates, the solenoid valve F is opened and the water pressure in the water feed line 18 drops which causes the water pressure sensitive switch M to close because the conduit 19 is in communication with the pipe 9 and with the conduit 18 through the valve body passage 20, see FIG. 6. The pump J operates and feeds water from the reservoir D to the ice maker B, as long as necessary. When the valve body H2 is in AUTO position, as shown in FIG. 6, another passage 22 in the valve body H2 places the inlet pipe 6 for the pump in communication with a stub pipe 23 that communicates with the reservoir D. Therefore, water will flow from the reservoir through the pipe 23, valve body passage 22, pipe 6, pump J, pipe 9, L-shaped passage 20 in the valve body H2, conduit 18, inlet 4, solenoid valve F, and conduit 21 to the ice maker B. The pump continues operating as long as it is necessary to supply all of the water needed for the cycle and it will then shut off when the water pressure in the line 18 reaches the high limit shut-off point which could be ten pounds and not over twenty pounds. The pump will not remain inoperative so far as the ice maker is concerned until the next ice maker cycle is reached and the low pressure in the conduit 18 causes the pressure sensitive switch to restart the motor and pump to repeat the operation we have just described. We will now set forth the operation of our device when water is needed for the ice water dispenser. Referring again to FIG. 1, it will be seen that the standard refrigerator shown in that Figure has a conduit 23' extending from the solenoid valve G to a water cooling tank N, and a conduit 24 extends from the cooling tank to the ice water dispenser C. An electric switch 25 is positioned in back of the lever P in the water dispenser C and when this lever is manually depressed by placing a cup against it for receiving ice water from the dispenser, the switch is closed and will cause an electric current to open the solenoid valve G. The drop in water pressure in the conduits 23' and 24 caused by the water in the dispenser C flowing into the cup, not shown, will cause a similar drop in water pressure in the conduit 18 that also feeds water to the solenoid valve G. This water pressure drop will be carried to the pipe 9 through the L-shaped passage 20 in the valve body H2 and to the pressure sensitive switch M through the conduit 9 with the result that the switch M will be closed to start the motor K and the pump J. The pump will deliver water to the cooling tank N, and will cause ice water to flow from the tank and out the dispense C. As soon as the lever P is freed the switch 25 will open and the solenoid valve G will close. The water pressure in the conduit 18 will build up to a point where it will open the pressure sensitive switch M and stop the motor and pump from operating. We have already mentioned that the installation of our device on a standard refrigerator requires no plumbing changes and can easily be installed by the buyer. The electric motor K can be connected to any house electrical outlet by the wires 26, shown in FIG. 1. The reservoir is placed on top of the refrigerator or any other convenient location near the refrigerator and the conduit 18 is connected to the water inlet 4 for the refrigerator. The operation for filling or refilling the reservoir D has been described and so has the operation for delivering water under pressure from the reservoir D to the ice maker B, or the ice water dispenser C. These last two operations take place automatically when needed as soon as the operator swings the handle 15 to AUTO position in FIG. 1. Our device can be used to eliminate inconvenient installations such as: an inside wall; in apartments where plumbing changes are not permitted; and places where water is not readily available for the ice maker B. Other possible uses are where colored ice cubes are to be used for a party. Colored water would be placed in the water source E and pumped into the reservoir D, as already explained. Where the water quality is poor, the water source E could contain water of the desired quality. Our device can be economical for persons who move a great deal and do not wish recurring plumbing charges. The refrigerator can be moved more readily because there is no permanent plumbing fixture. On one filling of the reservoir with water our device would function from one week to several months, this depending how often ice cubes are needed and how often ice water is drawn from the dispenser C.
A refrigerator water reservoir that takes the place of connecting the refrigerator to the city water supply, the reservoir being connected to the automatic ice maker and to the ice maker dispenser for automatically delivering water to either unit as soon as the ice maker starts operating or when the ice water dispenser is actuated. No alterations are necessary to be made in a standard refrigerator that is already equipped with the automatic ice maker and with the ice water dispenser. The water reservoir assembly is equipped with a motor driven pump and with a water pressure sensitive switch so that the water in the conduit leading from the reservoir to the two solenoid valves, which in turn control the flow of water to the ice maker and to the ice water dispenser, will be maintained at a desired water pressure at all times. The device also has manually controlled means for refilling the reservoir when needed.
5
FIELD OF THE INVENTION This invention relates generally to an antenna apparatus, system and method for receiving and transmitting cellular telephone signals. More particularly, the invention relates to a dipole antenna coupled to a transmission line that is printed on a vehicle window. BACKGROUND A number of apparatus and methods exist for an antenna that utilizes the surface of a glass. For example, one type of antenna has been used exclusively for reception in the VHF band, having a low gain and an unfavorably high voltage standing wave ratio (VSWR). For practical reasons, pole or rod antennas have been used for portable communications services such as cellular telephones and for receiving global positioning satellite (GPS) signals. Rod and pole antenna typically extend outward from the automobile, and generally create noise at high speed, interfere with washing of the vehicle, can be snagged on low branches, and adversely affect the overall aesthetics of the vehicle. Dipole antennas typically appear as a metal rectangle on the end of a short mounting beam, and is the basic antenna for fixed point communications. Dipole antennas are omni-directional when vertically polarized and have relatively low gain. It is not common to use a dipole antenna in a horizontally polarized system because other antennas having higher gain and lower cost are readily available. As depicted in FIG. 1, shielded dipole antennas 10 are also known, for example, U.S. Pat. No. 4,746,925. The coaxial cable 12 must run across a window glass 14 , which is aesthetically unappealing and obscures driver or passenger visibility. Moving the antenna 10 closer to pillars or trim area 16 degrade performance as the dipole radiation pattern is severely distorted by the proximity of the surrounding metal, as well as significantly radiating into the vehicle. Consequently, there is a need for a dipole antenna that provides improved antenna performance and as well as improved aesthetic qualities. SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide an antenna system for the reception of cellular telephone signals and transmission of the cellular telephone signals to a cellular receiver, as well as the transmission of cellular signals from a cellular transmitter to external cellular receivers over a transmission line having an improved omni-directional antenna pattern when mounted on a vehicle window. Another object of the invention is to provide a dipole antenna mounted on the surface of a vehicle window that is in a clear path RF environment. Another object of the invention utilizes two sets of dipole antennas with a modified feed length, each antenna positioned on opposite sides of the vehicle providing enhancement of the radiation pattern. The present invention is directed to an automotive on glass antenna having parallel tuned feeders. Two sets of antenna elements are printed on a vehicle window and are tuned to an upper part of the desired frequency band and to a lower part of the desired frequency band. The antenna elements can be printed on the glass using techniques known in the art for printing rear defogger elements and AM/FM radio antennas onto glass. For example, in a cellular telephone application having a bandwidth of approximately 70 MHz, a VSWR of less than 2:1 can be maintained. Each tuned dipole antenna employs three elements to broad band the dipole antenna. A parallel tuned feeder for each antenna is a multiple electrical half wavelength to transfer the approximately 50 Ohm impedance of the dipole. Parallel tuned feeders transform the impedance of the coaxial cable to match the impedance of the antenna. The parallel tuned feeder allows for the placement of the printed modified dipole antenna in a clear path RF environment, resulting in a well-defined omni-directional antenna pattern. The printed antenna elements are connected to one end of a coaxial cable, which forms a coaxial transmission line. This coaxial transmission line has an impedance of approximately 75 Ohms and odd multiple electrical quarter wavelengths. One hundred-ohm transmission line combines in parallel to 50 ohms, feeding into a 50-ohm transmission line matching the impedance of the transmitter. This results in the power supplied at the feed point to be split and each antenna receives one-half of the input power. A relatively symmetrical radiation pattern is achieved by placing one of these dipoles on each side window of a vehicle having stationary window glass, resulting in space diversity. Additionally, by splitting the power equally between the antennas, the field strength is also divided, and the amount of RF exposure to the interior of the vehicle is reduced. One advantage of using two dipoles with space diversity is an improved radiation pattern versus a single dipole pattern. Use of window mount dipole antenna of this invention virtually eliminate rain leakage, are less costly that roof installed antennae, improves vehicle appearance, and can be utilized on all vehicles having a stationary or partially stationary window. Vehicle appearance is also improved by concealing the coaxial transmission line going to the transmitter, for example, beneath the roof liner. These and other features and advantages of this invention are described in or are apparent from the following detailed description of the preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiments of this invention will be described in detail, with reference to the following figures, wherein: FIG. 1 is a planar view of a single dipole antenna of the prior art; FIG. 2 is a perspective view of a dipole antenna of the invention on a side window of a vehicle; FIG. 3 is a close-up planar view from the outside of the vehicle of the antenna shown in FIG. 2 attached to the window; FIG. 4 is a diagram depicting a passive diversity antenna system with parallel tuned feeders of the invention; FIG. 5 depicts the min-max horizontal directional diagram of a prior art collinear antenna taken at 0 degrees with respect to the bottom of the antenna; FIG. 6 depicts the average gain of a prior art collinear antenna taken at 0 degrees with respect to the bottom of the antenna; FIG. 7 depicts the min-max horizontal directional diagram of a prior art collinear antenna taken at 20 degrees with respect to the bottom of the antenna; FIG. 8 depicts the average gain of a prior art collinear antenna taken at 20 degrees with respect to the bottom of the antenna; FIG. 9 depicts the min-max horizontal directional diagram of a prior art collinear antenna taken at 30 degrees with respect to the bottom of the antenna; FIG. 10 depicts the average gain of a prior art collinear antenna taken at 30 degrees with respect to the bottom of the antenna; FIG. 11 depicts the min-max horizontal directional diagram of a prior art collinear antenna taken at 40 degrees with respect to the bottom of the antenna; FIG. 12 depicts the average gain of a prior art collinear antenna taken at 40 degrees with respect to the bottom of the antenna; FIG. 13 depicts the min-max horizontal directional diagram of a passive diversity antenna system with parallel tuned feeders of the invention taken at 0 degrees with respect to the bottom of the antenna; FIG. 14 depicts the average gain of a passive diversity antenna system with parallel tuned feeders of the invention taken at 0 degrees with respect to the bottom of the antenna; FIG. 15 depicts the min-max horizontal directional diagram of a passive diversity antenna system with parallel tuned feeders of the invention taken at 20 degrees with respect to the bottom of the antenna; FIG. 16 depicts the average gain of a passive diversity antenna system with parallel tuned feeders of the invention taken at 20 degrees with respect to the bottom of the antenna; FIG. 17 depicts the min-max horizontal directional diagram of a passive diversity antenna system with parallel tuned feeders of the invention taken at 30 degrees with respect to the bottom of the antenna; FIG. 18 depicts the average gain of a passive diversity antenna system with parallel tuned feeders of the invention taken at 30 degrees with respect to the bottom of the antenna; FIG. 19 depicts the min-max horizontal directional diagram of a passive diversity antenna system with parallel tuned feeders of the invention taken at 40 degrees with respect to the bottom of the antenna; and FIG. 20 depicts the average gain of a passive diversity antenna system with parallel tuned feeders of the invention taken at 40 degrees with respect to the bottom of the antenna. Throughout the drawing figures, like reference numerals will be understood to refer to like parts and components. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As seen if FIGS. 2-4, which depict various details of the antenna assembly 20 of this invention, the antenna assembly 20 has two tuned dipole antenna 22 , 24 , each antenna 22 , 24 having at least two wires 26 mounted on a vehicle window 28 , and a parallel tuned feeder 30 , 32 electrically connected at a first end to each of the antenna 22 , 24 . Each parallel tuned feeder 30 , 32 is electrically connected at a second end to a coaxial cable 34 , 36 at combining points 38 , 40 . Both coaxial cables 34 , 36 are combined together at a combining point 42 , where another coaxial cable 44 electrically connects the two tuned dipole antenna 22 , 24 to a transceiver 46 . In the preferred embodiment, the dipole antenna 22 , 24 utilize three antenna wires, or elements 26 to broad band the dipole antenna. This method of broad banding is also known in the art as diversity feed, and two or mores wires are typically used to broad band. In FIG. 3, the two sets of antenna elements 26 are tuned for the upper and lower part of the desired frequency band. For a cellular telephone, when the bandwidth is 70 MHz, a VSWR of less than 2:1 can be maintained. The antenna 22 , 24 are preferably omni-directional in an elevation plane between 0 degrees and 60 degrees from the horizontal. The voltage standing wave ratio, VSWR, preferably has a value of 2 or less, where 1 is a perfect 50 ohm antenna. Parallel tuned feeders 30 , 32 are multiple electrical half wavelengths used to transfer the 50 Ohm impedance of the dipole at the combining points 38 , 40 . The dipole antennas 22 , 24 and the parallel tuned feeders 30 , 32 are preferably printed on the vehicle window 28 using existing technology, for example, printing automobile rear defogger elements and AM/FM radio antennas on glass. Coaxial transmission lines 34 , 36 have an impedance of 75 Ohms each and are odd multiple electrical quarter wavelengths. The coaxial transmission lines 34 , 36 combine at the combining point 42 at 100 ohms each, combining in parallel to 50 ohms. The parallel tuned feeders 30 , 32 transforms the impedance of the coaxial cables 34 , 36 to match the impedance of the antenna. The coaxial transmission line 44 , located inside the vehicle 54 , is connected to a transceiver 46 , transferring the RF signals to the transceiver 46 for conversion to audio. The coaxial transmission line 44 is 50 ohms to match the impedance of the transceiver 46 . In this manner, the power supplied at the transceiver feed point 48 is split at the combining point 42 and each dipole antenna 22 , 24 receives one-half of the power input. The transceiver 46 can be any radio frequency transceiver. In the preferred embodiment, the transceiver 46 is a cellular telephone, either analog, digital, or PCS, using any frequency assigned for the service. In the preferred embodiment, the transceiver 46 is a cellular telephone operating in the frequency range of approximately 820 to 900 MHz. In this manner, a relatively symmetrical radiation pattern is achieved by placing one of the dipole antennas 22 , 24 on each side window 50 , 52 of a vehicle 54 where the glass on the side windows 50 , 52 is stationary. Additionally, since the power is split equally, the field strength at each antenna 22 , 24 is also divided. On the reciprocal, the received signal can be added or subtracted at the combining point 42 . A total received signal of plus or minus 3 dB over a single dipole antenna 22 , 24 is possible, due to the combinations of instantaneous phase relationship at the antennas 22 , 24 . This equates to an amount equal to or slightly less than the received signal at the transceiver 46 when compared to a traditional roof mount antenna. The use of two dipole antennas 22 , 24 have the advantage of seeing both sides of the vehicle without obstruction versus a single dipole antenna on one side window. This is also known as space diversity. As depicted in FIGS. 2 and 3, the antennas 22 , 24 are attached to the vehicle side windows 50 , 52 near the center of the viewing area 56 . This effectively places the antennas 22 , 24 farthest away from any metal that can interfere with the operation of the antennas 22 , 24 , such as door trim 56 . The coaxial cables 34 , 36 , 44 are located beneath the headliner, not shown, for improved vehicle aesthetics. Alternatively, the coaxial cables 34 , 36 , 44 can be concealed beneath any interior panel, carpet, trim, and the like to effectively conceal and route the cables to the transmitter. FIGS. 5 to 12 show antenna patterns and average gain plots for a collinear antenna mounted on a vehicle known in the art. FIGS. 13-20 show antenna patterns and average gain plots for a dipole antenna of the present invention. The reported angle is with respect to the horizon, but referenced to the bottom of each antenna. Measurements were taken at 0 degrees, 20 degrees, 30 degrees and 40 degrees. All measurements were taken with vertical polarization. Antenna gain is a measure of how well the antenna will send or receive an RF signal. Gain is typically measured in decibels-isotropic, dBi, or in decibels-dipole, dBd. When using dBi, performance is a determination of how much better the antenna is compared to an isotropic radiator. An isotropic radiator is an antenna that sends signals equally in all directions. A true isotropic antenna has a 0 dBi gain. The higher the decibel figure, the higher the gain. For example, an antenna having a 6 dBi gain will receive a signal better than a 3 dBi antenna. Dipole antennas typically have a 2.4 dBi gain as dipole antennas are better than isotropic radiators. Additionally, dipole antennas are omni-directional when vertically polarized. The average gain for each antenna at each elevation angle is given as average gain and linear average gain. The average gain is determined as the average measured gain. The linear average gain is determined by taking the average gain values in dBi, converting those values to linear equivalent, averaging the linear values, and converting back to dBi. When the antenna pattern is perfectly symmetrical, the average gain and the linear average gain will be identical. When the antenna pattern is not symmetrical, the linear average gain will always be higher than the average gain. This in a result of the average gain not being indicative of the actual power under the curve. As seen in FIGS. 5 and 13, the prior art collinear antenna performed better than the dipole antenna of this invention at 0 degrees. In contrast, as seen in FIGS. 11 and 19, the dipole antenna of this invention performed better than the collinear antenna of the prior art as the angle increased. It will be readily understood, for example, that the dipole antenna of this invention performs better than the collinear antenna in hilly areas because the radiated energy approaches the antenna from elevated transmitters, resulting in an increased elevation angle. While advantageous embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention, as defined in the appended claims. For example, the parallel tuned feeder is not limited to the broadband dipole antenna, as many different types of antennas could be placed in the center area of a window while concealing the coaxial cable. Other antenna designs also using a tuned feeder could be used to steer the radiation pattern is desired. The transceiver can be any two-way communications device, including a wireless modem.
A glass antenna assembly for receiving and transmitting cellular telephone signals includes a two pair of dipole antennas, each pair mounted on a vehicle window. Space diversity is achieved by placing the vehicle windows with the antenna pair on opposite sides of the vehicle. This results in an improved omni-directional antenna pattern. Each dipole antenna is tunes, and employs at least three elements to broad band the dipole antenna. Coaxial feeders leading from the antenna assembly can be concealed under the roof lining for improved aesthetics.
7
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clothes dryer, and more specifically, to a housing for a lint filter in a dryer. 2. Description of the Prior Art Clothes dryers, in particular, automatic clothes dryers, generally include lint filtering screens provided in an air flow path downstream of a dryer tumbling drum so that lint and other particulate matter entrained in the air stream is filtered therefrom prior to the air being exhausted from the dryer unit. Generally, it is recommended that lint filters and screens be cleaned after each dryer load. However, cleaning of the lint filter is often neglected, allowing a quantity of lint to be deposited on the filter. Also, when certain types of articles are dried, greater quantities of lint than normal are produced, causing a heavy build-up on the lint filter. In any case, once the lint build-up has occurred, it impairs the operation of the dryer and, when the filter is removed for cleaning the lint tends to rub on the filter housing and fall off. For dryers having a lint screen at the dryer drum openings, lint falling from the lint screen usually drops into the dryer drum into the area occupied by the clothes load which undesirably redeposits the lint onto the clothes load. An attempted solution to the problem of lint falling from a lint screen into the dryer drum is disclosed in Steward U.S. Pat. No. 2,722,751 wherein a lint trap 104 is mounted in an air flow duct 63 to trap lint and water vapor entrained in the air flow. The lint trap 104 includes a pair of inwardly directed bent arms 113 on an inner surface of grip elements 109 which prevent accumulated lint from sliding or rolling off the lint trap should the operator fail to clean the lint trap for an extended period of time. Assignees copending application, Ser. No. 836,297 filed Mar. 5, 1986, utilizes a cover to solve this problem. SUMMARY OF THE PRESENT INVENTION An object of the present invention is to prevent accumulated lint on a lint filter screen from becoming dislodged and falling therefrom, such as when the lint filter is removed from the dryer unit. Another object of the present invention is to provide a high capacity lint filter with controlled lint build-up. These and other objects are accomplished by a shaped lint filter housing having a distended midportion and confined edge regions for accommodating and controlling the build-up on a lint filter removably mounted within the housing. Edge portions of the housing are relatively closely spaced from the accumulating face of the lint filter as it is disposed within the housing and the midportions of the housing are spaced relatively farther from the lint filter. During operation of the dryer, lint is first uniformly deposited over the entire collecting surface of the filter. As more lint is accumulated it reaches the edge portions of the housing thereby limiting further lint build-up on the filter around the peripheral edge of the filter. Any additional lint accumulation, thus, occurs in the region of the distended midportion of the housing. It has been found that by limiting lint build-up at the edges of a lint filter, the likelihood of the lint mat becoming dislodged as the filter is removed is significantly reduced. Having the midportion of the housing spaced further from the filter also provides an unhindered air flow path so that there is less impairment of the dryer operation when cleaning of the filter has been neglected for several loads. Thus, more lint can be accumulated on the present screen, particularly as a result of the shaped housing. Therefore, a significant accumulation of lint on the lint screen can be withdrawn from the lint screen housing of the present invention without risk of the lint dropping onto a freshly laundered load of clothes. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a clothes dryer unit including the lint filter assembly of the present invention; FIG. 2 is an enlarged cross section along the line II--II of FIG. 1 showing the lint filter duct portion of the lint filter assembly; FIG. 3 is an enlarged cross section along line III--III of FIG. 1 showing the lint filter housing and grill mounted to the lint filter duct; FIG. 4 is a cross section along line IV--IV of FIG. 3 showing the lint filter assembly; FIG. 5 is a cross section along line V--V of FIG. 3 showing the mounting method for the lint filter assembly; FIG. 6 is a cross section along line VI--VI of FIG. 2 showing the top of the lint filter assembly; FIG. 7 is a cross-section along line VII--VII of FIG. 2 through the lint filter assembly; and FIG. 8 is an elevational view of the lint filter housing and duct removed from the dryer. DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, there is shown an automatic clothes dryer at 10 having an exterior cabinet 12 with a top panel 14 having a control console 16 along the rear portion thereof incorporating a plurality of controls 18 for selecting an automatic programmed series of drying steps. The dryer cabinet 12 has a front openable door 20 providing access to the interior of a rotatable drying drum 22 which rotates about a horizontal axis and has a non-rotating rear bulkhead 24 with air inlets (not shown) connected to a heater 26, as well as a non-rotating front bulkhead 28 having air outlets 30 therein, for charging the interior of the drum 22 with heated air and for exhausting moisture-laden air, respectively. An electric motor 32 is provided to rotate the drum 22 through a pulley arrangement 34 and a belt 36, the drum 22 being rotated on a plurality of rollers 38. The motor 32 also drives a blower 40 which draws air through the air outlets 30 and through a lint filter 42 in a lint filter assembly 44 and, thus, provides an air flow stream through the interior of the drum 22 and the lint filter assembly 44. Referring to FIG. 2, the front bulkhead panel 28 is shown from the front with the cabinet 12 removed. The lint filter assembly 44 is mounted to the front bulkhead 28 and to the blower 40, which is connected to an exhaust conduit 46 through a blower housing 48. The lint filter assembly 44 channels air flowing from the front bulkhead 28 to the blower 40 so that the blower can force the air through the blower housing 48 and out the exhaust conduit 46. The lint filter assembly 44 is made up of a lint filter duct 50 at the front and a lint filter housing 52 at the back as shown in FIG. 3. The filter housing 52 is joined to the filter duct 50 by a crimped connection at edges 54. The filter duct 50 is mounted to the bulkhead panel 28 by a pair of bolts 56. Above the filter duct 50 is a housing outlet panel 58, also mounted to the bulkhead panel 28 by bolts 60 extending through lateral tabs 62. In FIG. 3, a view of the front bulkhead 28 and filter assembly 44 as seen generally from inside the dryer is shown. A grill 70 is provided over an opening in the bulkhead panel 28 to form the air outlets 30 from the drum, which are also the air inlets to the filter assembly 44. Behind the grill 70 is the filter 42 which includes a filter handle 72. The grill 70 includes a curved recess 74 adjacent the handle 72 to provide access to the handle 72. The lint filter 42, which is preferably a screen, fits into the filter housing 52, which has a general pocket shape extending below the grill 70. As shown generally at 76, a deformation is included in the lint filter housing 52 spanning the center thereof below the grill 70. The deformation 76 is spaced further from the screen 42 than the balance of the housing 52. Referring now to FIG. 4, the grill 70 is shown affixed to the bulkhead 28 by a screw 78, the grill 70 providing air access to and being upstream of the screen 42. The lint filter 42 includes a frame 80 with an upstream edge 81 within which is stretched the screen or other filter element that forms a lint collecting surface 82 on its upstream side. Peripheral edge portions 84 of the filter housing 52 are spaced from the lint collecting surface 82 only by the depth of the frame 80, while the distended midportion 76 of the housing 52 is spaced relatively further away from the lint collecting surface 82 of the lint screen 42 to provide additional space for the lint to accumulate. In FIG. 5 the connection to the dryer bulkhead 28 of an imperforate frame 85 of the grill 70 by the screw 60 is shown. The tab 62 is also fastened by the same screw 60. The crimped edge 54 can be seen in line with the fastening bolt 56 for the filter assembly 44. In the top view of FIG. 6, the grill 70 and a portion of the outlet panel 58 define a slot S through which the filter 42 is slidably inserted and removed. The width of the slot S, and particularly the distance from the lint accumulating face 82 of the filter 42 to a forward edge E of the grill 70, permits removal of the lint filter 42 without dislodging the lint mat thereon. In FIG. 7 a cross section through the lint filter assembly 44 reveals the lint screen 42 in position and its relationship to the front lint duct 50 and the rear lint housing 52. The peripheral edge regions 84 of the housing 52 define a distance A from the lint collecting surface 82, while the midportion 76 defines a greater distance B from the surface 82. The upstream edge 81 of the frame 80 rides against and abuts the peripheral edge regions 84 of the housing 52. Thus, lint can accumulate on the edge regions of the screen 42 to a depth A, further build-up being limited by the edge regions 84, yet the lint can continue to accumulate at the center of the screen 42 to a depth B. As can be seen by comparison of FIGS. 7 and 3, the deformed midportion 76 includes a lesser spaced sub-region 86 at a distance C to accomodate the roller 38 on which the dryer drum 22 rotates. The screen 42 slidably moves within the filter assembly 44, portion of the frame 80 being received between the duct 50 and the housing 52 as shown at the right side of FIG. 7. Other portions of the frame 80 are held against the housing 52 by a channel 88 as shown at the left of FIG. 7. In FIG. 8, the disembodied lint filter assembly 44 is shown, including two mounting tangs 90 by which the entire assembly 44 can be mounted in the dryer 10 by the bolts 56. The channel 88, shown in dotted outline, extends in a J-shape along the inside surface of the housing 52 to hold a portion of the filter frame 80 when the filter 42 is slidably received into the lint assembly 44. The region 84 of the housing 52 extends around nearly all of the filter 42 that is within the assembly 44 to limit lint build-up to the depth A. A greater build-up is permitted at the regions 76 and 86 without affecting the ability to remove the lint-loaded filter 42 and without having the lint accumulation undesirably come off. The regions 76 and 86 are generally of the same shape as the filter 42 which fits therein, but are of a smaller size. Although the present invention has been disclosed in conjunction with a flow-through type dryer, the use of a similarly shaped lint filter housing is contemplated in other types of dryers as well. Thus, the present invention provides a housing for a lint filtering screen with restricted edges portions to limit lint build-up thereat and a distended midportion to permit a greater depth of lint to accumulate. As is apparent from the foregoing specification, the invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. It should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art.
An automatic clothes dryer includes a lint screen mounted within a lint screen assembly to filter lint entrained in an air flow stream during the drying operation. The lint screen assembly includes a shaped housing spaced close to the peripheral edges of the screen's lint collecting surface, yet spaced further from the screen's midportion to enable quantities of lint to accumulate on the screen and still be removed from the dryer without the risk of the lint falling from the lint screen. The lint screen assembly is held within the dryer only by a pair of fastening screws.
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CROSS-RELATED APPLICATION This application is a continuation-in-part of copending application Ser. No. 324,075 (now abandoned) filed Jan. 16, 1973 and claiming the priority of the applications filed in France on Jan. 4, 1972 and Dec. 7, 1972. BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to an apparatus for the production of covered warp yarns for textile fabrics, and to the fabric produced thereby. 2. Description of the Prior Art In order to weave, on high output shuttleless looms, tapes and other textile fabrics wherein covered yarns are used, it is necessary before weaving to carry out the covering operation, i.e. to wrap about the yarns to be covered coverings of textile material. Such covering is conventionally effected by helically winding a covering yarn about each yarn to be covered. For this purpose, it is necessary to utilize costly equipment. Taking account of the labor necessary, of the space occupied in the mill, and of the various manipulations and handling operations required, it appears that the covering currently doubles the basic price of the yarn to be covered, particularly when the yarn is a rubber filament. Such known covering, despite the precautions taken, also results in differences in tension in the covered yarns, in particular if these yarns are elastic filaments, and consequently snarling, kinking and undulation effects in the woven articles. SUMMARY OF THE INVENTION According to one aspect of the present invention, there is provided a method of producing a textile fabric, comprising covering warp yarns with covering yarns while said warp yarns are in a loom, and weaving the thus covered warp yarns with weft yarns while said warp yarns are in the loom. According to another aspect of the present invention, there is provided apparatus for producing a textile fabric, comprising a loom, covering means in said loom for covering the warp yarns with covering yarns, and weaving means in said loom for weaving the thus covered warp yarns with weft yarns. According to a further aspect of the present invention, there is provided a device for covering warp yarns with covering yarns, comprising a longitudinally reciprocable row of yarn guides for the respective warp yarns, a reciprocable row of needles extending substantially parallel to said row of yarn guides, and a longitudinally reciprocable row of covering yarn displacing members extending substantially parallel to said row of yarn guides for cooperating with said row of needles to cover said warp yarns with said covering yarns in the form of rows of loop stitches. According to a yet further aspect of the present invention, there is provided a woven fabric comprising weft yarns, warp yarns and covering yarns covering said warp yarns, said covering yarns being in the form of rows of loop stitches which were applied to said warp yarns prior to weaving of said weft yarns and said warp yarns. By means of the invention, it is possible to obtain articles of improved strength, greater stability and neat appearance. Moreover, they may incorporate surface effects of various kinds. BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may be clearly understood and readily carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: FIG. 1 is a diagrammatic perspective view illustrating a method of production of a woven tape, FIG. 2 is a perspective view illustrating, to an extremely large scale, a warp yarn covered by a covering yarn, FIG. 3 is a diagrammatic perspective view of the rear of a loom including a covering device, FIG. 4 shows a detail of FIG. 3, and in particular the covering device, FIG. 5 is a diagrammatic sectional view of the covering device, FIG. 6 is a diagrammatic plan view of a modified version of the covering device, FIG. 7 is a diagrammatic sectional view of the modified version, FIG. 8a and 8b are diagrammatic sectional views of a second modified version of the covering device in different positions of operation, and FIG. 9 is a fragmentary plan view of this second modified version. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The woven tape R shown in FIG. 1 comprises warp yarns 1 each covered with a covering yarn 2, which covering yarn 2 surrounds the warp yarn in chain stitches. The warp yarns 1 are rubber filaments. The formation of tape R is effected in a high-output shuttleless loom, in this case a loom having one or more sickle-shaped weft inserters, for example of the kind disclosed in British Patent Specification No. 1274546. However, it is not excluded that the method could be performed on a shuttle loom. The tape R is woven on the loom which at the rear thereof includes a covering device. FIG. 3 shows lateral frame members 3 of the loom which carry a weftwise bar 4 which supports yarn-displacing members in the form of yarn guides 5 for the covering yarns 2. The bar 4 is angularly displaceable to-and-fro as indicated by the arrows F, and is longitudinally reciprocable as indicated by arrows F1. For the sake of clearness, only one block of yarn guides 5 for one tape is shown in FIGS. 3 to 5. A weftwise bar 6, carried by the frame members 3 of the loom, mounts eyed yarn guides 7, only one block of which is shown in the drawings, for the warp yarns to be covered. The bar 6 is longitudinally reciprocable as indicated by arrows F2. The yarns 1 are disposed, provisionally sized, in the form of a band, in a container C. Before travelling to the bar 6 and the yarn guides 7, the yarns 1 pass through a positive feed means 8, the rollers of which rotate at greatly reduced speed imparted, through optional intermediate means, by the driving mechanism of the loom. The lateral frame members 3 of the loom also carry a weftwise bar 9 on which is secured a needle-clamping plate 10. Positioned in slots 10a of the plate are latch needles 11 each terminating at its upper end in a hook 11a and having a latch 11b. The bar 9 is reciprocable lengthwise of the needles as indicated by arrows F3. A weftwise bar 12 which extends proximate the upper ends of the needles 11, is carried by the lateral frame members 3. A guiding and retaining plate 12a secured to the bar 12 above that bar serves with the bar as a guide for feeding covered warp yarns 1a from the covering device to the weaving means of the loom. As already noted, the weaving means of the loom includes a sickle-shaped weft inserter system. There are as many groups of needles and yarn guides as there are tapes. Save for the bar 12, which is fixed, the weftwise bars 4, 6 and 9 are fitted with the necessary clearance or play in sliding and/or pivoting bearings in the frame members 3 of the loom. In order to achieve the various displacements indicated in respect of the bars 4, 6 and 9, movement take-off is effected from the driving mechanism of the loom via a take-off shaft 13. There is driven from a counter shaft 13a, itself driven from the take-off shaft 13, a cam 14, which acts to displace vertically a connecting rod 15. The latter periodically urges a lever 16, keyed on the end of the bar 4, against the action of a spring so as to produce the angular to-and-fro displacements of the bar 4. To the other end of the bar 4 there is imparted, by a cam 17, the longitudinal reciprocation of that bar, and return is provided by a return spring (not shown). The cam 17 is driven from the counter shaft 13a. The longitudinal reciprocation of the bar 6 is produced by a cam 18 acting under driving means similar to those of the cam 17 and having a return spring (not shown). The reciprocation of the bar 9 lengthwise of the needles 11 is obtained by means of cams 19, only one of which is shown, acting at the ends of the bar, against respective followers 20. A shaft upon which the cams 19 are mounted is driven by means of a chain 21 from the counter shaft 13a. These various displacements are, of course, appropriately synchronized and coordinated so as to form the chain stitches in covering yarns 2 about the elastic filaments 1. The velocity of the displacements may be varied in such a manner as to obtain more or less tight covering of the warp yarns 1. In this way, it is possible to modify the appearance of the covered yarns and of the woven article, thereby imparting to them a thicker, more considerably "bulked" or more costly appearance, even if the covering yarns are extremely fine. Upon leaving the covering device, the covered yarns 1a pass around a roller 22, thus to be directed, as indicated by arrow F4, towards the weaving means of the loom where the covered warp yarns are woven with the weft threads. The articles thus woven are, furthermore, neater and more uniform, owing to the uniformity of the rubber filaments which are covered simultaneously, starting from the same initial tension, such tension not being substantially modified during the operations. There is substantially no deformation, buckling or snarling in the articles produced by considerable variations in the tension in the covered filaments. Referring to the modified form of covering devices shown in FIGS. 6 and 7, the weftwise bar 6 and the yarn guides 7 of the above described covering device are replaced by a single angle member 23 which is formed with a series of orifices 23a for the passage of the warp yarns 1. The member 23 is disposed between a row of needles 24, mounted on a weftwise bar 31, and a row of yarns guides for the covering yarns. These guides are arranged in blocks 25 mounted on a weft-wise bar 33. The rows of needles 24 and the yarn guides of the blocks 25 are oppositely aligned, the needles and the guides extending at an angle of approximately 30° relative to the horizontal, so as to promote closure of the needle latches. The various means 23, 24 and 25, involved in the covering method, are controlled from a main shaft 26 receiving its rotarty drive from a motor (not shown) via pulleys 27 and a belt 28 which connect the main shaft 26 to a 1/1600 speed-reducing assembly 29. Mounted on the main shaft 26 are two eccentric members 30 which impart reciprocatory movement to the bar 31 lengthwise of the needles 24. A further eccentric member 32 mounted on the main shaft 26 imparts to the bar 33 an angular to-and-fro movement. The main shaft 26 transmits drive, through bevel gears 34 and 35 having a 1:2 reduction ratio, to a secondary shaft 36 on which is mounted eccentric member 37. The member 37 imparts to the angle member 23 longitudinal reciprocation. A second eccentric member 38, mounted on the shaft 36, imparts longitudinal reciprocation to the bar 33. As with the previously described device, the various displacements are appropriately synchronized and coordinated so as to form the chain stitches in the covering yarns 2 about the filaments 1. According to a further modified version of the covering device (see FIGS. 8 and 9), covering is effected by means of two rows of needles 39 positioned approximately at 30° relative to the horizontal and disposed opposite each other, the warp yarns to be covered travelling between the needles through orifices 40a formed in a tapered support member 40. There is imparted to member 40 longitudinal reciprocation, and to the rows of needles 39 both longitudinal reciprocation and reciprocation lengthwise of the needles. The two needles cooperate with a yarn guide 25' similar to that as shown in FIG. 7, this yarn guide undergoing rocking movement and cooperating with the needles successively so that a chain stitch cover is formed on the warp filament. As is seen in FIGS. 8a and 8b when one needle is retracted and its latch is closed so that it engages the cover yarn 2, the other needle is extended and its latch is open so that the cover yarn is released. The needles reciprocate in the manner as shown in FIG. 8a and 8b and successively engage the cover yarn to form chain stitches around the warp yarn. It is also possible for each row of needles to be associated with a respective yarn guide and cover yarn in which case the warp yarn can be covered with two separate cover yarns. It is not excluded in the case of any of the embodiments of the covering devices, as above described, to cover with more than two covering yarns per warp yarn. To do this, the needles are arranged in fan-like arrays on opposite sides of the warp yarns. It is also possible to combine a plurality of rows of needles with a plurality of yarn guides, thereby making it possible to diminish the operating velocities and accelerations of the moving parts. It should also be noted that, although the various embodiments of covering device are generally mounted on the loom so as to feed covered warp yarns directly to the weaving means thereof, it is nevertheless possible to provide an independent covering device which could be fitted on a loom or function independently thereof. In either of the latter cases, the device requires an amount of space which is small relative to that required by conventional covering devices. It should be noted that the covering of warp yarns by successive chain or other loop stitches tends to prevent deterioration if the warp is accidently cut, since the covered yarns retain the warp yarns and prevent them from being withdrawn from the cut portion if the warp yarns are resilient, whereas in conventional i.e. helical covering, it is the warp yarns which retain the covered yarns and, if the warp yarns are cut, the covering rapidly deteriorates. It should be further noted that the covered warp yarns have a predetermined degree of roughness and that they are more bulky in cross-section then yarns covered by helical winding. This means that woven fabric is of improved strength. The filaments which are covered may be of natural or synthetic elastomeric or non-elastic material.
Covered warp yarns or cords are produced by feeding to a warp-knitting device thick warp yarns, especially of elastomeric material, and thin yarns which are knitted around the respective thick warp yarns as rows of chain or other loop stitches. The warp cords so produced are woven as warp threads in a conventional manner with weft threads in a loom which preferably includes the warp-knitting device.
3
CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 62/026,251, filed Jul. 18, 2014, the disclosure of which is hereby incorporated by reference thereto in its entirety. BACKGROUND [0002] The invention relates to an airbag system and, more particularly, to an airbag rescue or safety system and, more particularly, an airbag system employed as a life-saving system to enable a person using such system to survive an avalanche, or analogous situation, such as to facilitate a water rescue, e.g., as well as an airbag system for attachment to, and for recovering, equipment of the person, such as a snowmobile. In these regards, the invention relates to such systems disclosed in U.S. Pat. No. 8,876,568, the disclosure of which is hereby incorporated by reference thereto in its entirety. The system of US '568 employs a battery-powered electric motor to turn the blower, i.e., the fan, turbine, or impeller, e.g., to inflate the airbag. However, the invention also encompasses an airbag rescue or safety system that relies upon a compressed gas or air cartridge to inflate the airbag. [0003] More particularly, the invention relates to a triggering device for an airbag rescue system. [0004] A system of the aforementioned type can be used when activated (either remotely or manually by the user) to maintain the user or the user's equipment buoyant during an avalanche, or analogous situation, and to maintain the user or equipment on the surface of the avalanche, or as close to the surface as possible, thereby enabling the user to survive the avalanche or to facilitate recovery of the user's equipment. [0005] In a further particular implementation, the field of invention relates to an airbag system utilized with a harness or backpack to be worn by a skier, snowboarder, snowmobiler, hiker, or a person engaged in another activity, who risks being exposed to an avalanche. SUMMARY [0006] The invention includes an airbag system and, particularly, an avalanche airbag system, and a triggering device therefor, whether such system is of the compressed air or gas cartridge type or another type, such as one that utilizes an electrically powered blower to inflate the airbag. More particularly, the invention relates to components of a triggering device for such an airbag system for initiating the inflation of the airbag, particularly while the airbag is supported on a person by means of a backpack or a harness. [0007] An airbag rescue system encompassed by the invention includes: an inflatable airbag designed to be in a non-deployed position or a deployed and inflated position; an air movement device comprising at least one of the following: a source of compressed gas or air or an electrically powered air mover that includes a bladed rotor; a supporting apparatus comprising a harness or a backpack designed to support the inflatable airbag and the powered air movement device on the user in a ready position of the airbag rescue system; a base plate fixed to the supporting apparatus; a triggering device designed to be manipulated by the user according to at least first and second manipulations to initiate inflation of the inflatable airbag, the triggering device comprising: a base fixed in relation to the base plate, the base including a blocking part; a trigger handle designed for movement by the user, in relation to the base, from a non-airbag-inflation-initiation position to an airbag-inflation-initiation position; a safety lock designed for movement by the user, in relation to the base, from a locked position and an unlocked position; said movement of the safety lock comprising the first manipulation of the triggering device, and said movement of the trigger handle comprising the second manipulation of the triggering device; and in the locked position of the safety lock, the safety lock engages the blocking part and blocks the movement of the trigger handle, and, in the unlocked position of the safety lock, the safety lock is not blocked by the blocking part of the base. [0018] According to a particular embodiment, the supporting apparatus comprises a shoulder strap and the base plate is fixed in relation to the shoulder strap. [0019] In one embodiment, the safety lock is mounted over the base and the movement of the safety lock is transverse in relation to the base. [0020] In one embodiment, the safety lock is mounted over the base and the movement of the safety lock is rotational in relation to the base. [0021] Further, according to the invention, the triggering device further comprises a cable extending between the trigger handle and the supporting apparatus. [0022] According to another particular embodiment, the base has a tubular shape and extends from the base plate in a direction to the trigger handle, the trigger handle slidably mounted on the tubular base. Further, the cable of the triggering device is fixed in relation to the trigger handle and extends through the tubular base and the cable and a cable housing extend between the base plate and the supporting apparatus. [0023] In a particular embodiment in which the air movement device is an electrically powered air mover, the invention further includes an electric power switch designed to activate the electrically powered air mover, and the cable is connected to the electric power switch. [0024] A particular feature of the invention relates to the trigger handle being externally accessible and includes no pocket or cover so as to maintain the trigger handle in a ready position. More particularly, according to a particular embodiment, the trigger handle is suspended from the base plate. [0025] In a particular embodiment of the invention, the supporting apparatus comprises a closeable airbag compartment containing the airbag in the non-deployed position, and the airbag compartment includes an opening system to allow the airbag to emerge from an opening in the compartment upon the initiation of the inflation of the airbag by the triggering device. [0026] More particularly, the opening system can comprise a readily burstable slide fastener that releasably closes the opening of the airbag compartment and is designed to open upon inflation of the airbag. The aforementioned cable is operably connected to the air movement device to activate either the source of compress air or the electrically powered air mover upon initiation of the inflation of the airbag by the triggering device. [0027] In another particular embodiment of the invention, the air movement device is an electrically powered air mover comprising a power switch, and the cable is operably connected to the power switch to activate the electrically powered air mover upon initiation of the inflation of the airbag by the triggering device. [0028] As an alternative to a readily burstable slide fastener to releasably close the airbag compartment, the opening system can include a lid and a latch mechanism to releasably secure the lid over the opening. The latch mechanism comprises a latch fixed to one of a surface of the compartment or a surface of the lid and a post fixed to a second of the surface of the compartment or the surface of the lid, and whereby the cable is operably connected to the air movement device to activate either the source of compress air or the electrically powered air mover. [0029] An airbag rescue system encompassed by the invention also includes: an inflatable airbag designed to be in a non-deployed position or a deployed and inflated position; an gas or air movement device comprising at least one of the following: a source of compressed gas or air or an electrically powered air mover that includes a bladed rotor; a supporting apparatus comprising a harness or a backpack designed to support the inflatable airbag and the air movement device on the user in a ready position of the airbag rescue system, the supporting apparatus comprising first and second shoulder straps; a base plate fixed in relation to the first shoulder strap; a triggering device designed to be manipulated by the user to initiate inflation of the inflatable airbag, the triggering device comprising: a base fixed in relation to the base plate; a trigger handle designed for movement by the user, in relation to the base, from a non-airbag-inflation-initiation position to an airbag-inflation-initiation position; a supplemental triggering mechanism comprising a lanyard having a first end fixed in relation to the trigger handle and a second end having a releasable clip; the lanyard having a length designed to allow the releasable clip to removably fasten the lanyard to a second location spaced apart from the trigger handle. [0039] According to the invention as described above, the second location can be the second shoulder strap and the lanyard can extend between the first and second shoulder straps. [0040] With further regard to the invention as described above, the base plate is removably fixed in relation to the first shoulder strap to allow relocating the base plate to be fixed in relation to the second shoulder strap. [0041] An airbag rescue system encompassed by the invention also includes: an inflatable airbag designed to be in a non-deployed position or a deployed and inflated position; an air movement device comprising at least one of the following: a source of compressed gas or air or an electrically powered air mover that includes a bladed rotor; a supporting apparatus comprising a harness or a backpack designed to support the inflatable airbag and the air movement device on the user in a ready position of the airbag rescue system, the supporting apparatus comprising at least one shoulder strap; a base plate fixed in relation to the shoulder strap; a triggering device designed to be manipulated by the user to initiate inflation of the inflatable airbag, the triggering device comprising: a base fixed in relation to the base plate and having a length extending from the base plate; a trigger handle slidably mounted along the length of the base for movement by the user from a non-airbag-inflation-initiation position to an airbag-inflation-initiation position; at least one detent, or detent recess fixed at a predetermined position along the length of the base to engage a portion of the trigger handle during the movement of the trigger handle but before the trigger handle reaches the airbag-inflation-initiation position to thereby provide physical feedback to the user of an impending triggering of the inflation of the airbag. [0050] According to the invention as described above, the at least one detent or detent recess and the portion of the trigger handle are made of materials and are arranged in relation to each other to require a force between 50 and 150 Newtons to be applied to the trigger handle to move the portion of the trigger handle beyond the detent or detent recess to enable the trigger handle to the airbag-inflation-initiation position. [0051] With further regard to the invention as described above, at least one of the detents or the portion of the trigger handle comprises an elastically deformable material. [0052] With further regard to the invention as described above, there are two detents or detent recesses spaced apart from each other. BRIEF DESCRIPTION OF THE DRAWINGS [0053] Other features and advantages of the invention will be better understood from the following description, with reference to the annexed drawings illustrating, by way of non-limiting embodiments, how the invention can be implemented, and in which: [0054] FIG. 1 is a perspective view of an airbag rescue system according to the invention in the form of a pack being worn by a user and in a ready position, the triggering device being positioned for activation; [0055] FIG. 2 is a front view of a pack according to the invention, having a different trigger handle from that of the rescue system pack of FIG. 1 ; [0056] FIG. 2A is a view of the pack of FIG. 2 being worn, with the airbag being stowed, non-deployed, within a compartment of the pack; [0057] FIG. 2B is a view of the pack of FIG. 1 being worn, with the airbag being inflated in the deployed position; [0058] FIG. 3 is partial view of a pack of the invention employing a lanyard connected to a left shoulder strap with an end clipped thereto; [0059] FIG. 4 is a partial view like that of FIG. 3 , with the end of the lanyard clipped to the right shoulder strap to provide additional triggering options in the event access to the trigger handle itself were to be difficult during an avalanche situation; [0060] FIG. 5 is a partial view of a shoulder strap to which the triggering device is affixed, showing the trigger handle in the non-airbag-inflation-initiation position; [0061] FIG. 6 is a partial view like that of FIG. 5 , showing the trigger handle in the airbag-inflation-initiation position and showing a recess/detent on the base of the triggering device that had engaged a portion of the trigger handle as it had been pulled longitudinally away from the base plate of the triggering device, the base plate being fixed to the shoulder strap; [0062] FIG. 7 is a partial view of a pack according to an embodiment, showing a lid closed on a top opening of the airbag compartment of the pack; [0063] FIG. 8 is a partial view of the pack according to FIG. 7 in a front view; [0064] FIG. 9 is partial view of the pack of FIG. 7 , showing the post (fixed to the lid) of a latch mechanism having been released from the latch (fixed to an upper portion of the pack); [0065] FIG. 10 is a partial view of the pack of FIG. 9 , showing the airbag beginning to emerge from its compartment of the pack; [0066] FIG. 11 is a partial view of the pack of FIG. 10 in a front view; [0067] FIG. 12 is a partial view of the pack of FIG. 11 , showing the lid more widely open and the airbag further expanding from its compartment; [0068] FIG. 13 is a partial view of the pack of FIG. 12 , in perspective, showing the airbag having expanded further from its compartment; [0069] FIG. 14 is an exploded perspective view of a triggering device according to the invention, with the trigger handle of FIG. 1 ; [0070] FIG. 14A is a cut-away side view of the triggering device of FIG. 14 ; [0071] FIG. 14B is a perspective cut-away view of the triggering device of FIG. 14 ; [0072] FIG. 15 is a schematic exploded view of a latch mechanism and associated portions of a pack and pack lid according to an embodiment of the invention; [0073] FIG. 16 is an exploded view of the latch mechanism, showing interior components of the latch case of the mechanism of FIG. 15 ; [0074] FIG. 16A is a top view of the latch case of FIGS. 15 and 16 , assembled; [0075] FIG. 16B is a cross-sectional view taken along line 16 B- 16 B of FIG. 16A ; [0076] FIG. 16C is a cross-sectional view taken along line 16 C- 16 C of FIG. 16A ; [0077] FIG. 17 is a top view of a trigger handle of the triggering device of an embodiment of the invention shown in FIG. 2 , showing a slide lock thereof in an unlocked position, allowing the trigger handle to be pulled away from the base plate along the base of the triggering device; [0078] FIG. 17A is a cross-sectional view of the trigger handle of FIG. 17 taken along line 17 A- 17 A of FIG. 17 ; [0079] FIG. 17B is an enlargement of a portion of the trigger handle of FIG. 17 , taken around the line 17 B- 17 B of FIG. 17 , showing the handle in the unlocked position; [0080] FIG. 18 is a top view of a trigger handle of the triggering device shown in FIG. 17 , showing the slide lock thereof in a locked position, preventing the trigger handle to be pulled away from the base plate along the base of the triggering device; [0081] FIG. 18A is a cross-sectional view of the trigger handle of FIG. 18 ; [0082] FIG. 18B is an enlargement of a portion of the trigger handle of FIG. 18 , showing the handle in the locked position; [0083] FIG. 19 is an exploded perspective view of a significant components of triggering device, showing the base plate, retaining flange, and base, which are designed to be fixed to a shoulder strap, as well as movable components, such as the trigger handle, safety lock, and cable. [0084] FIG. 20 is an exploded perspective view of the latch mechanism, similar to the view of FIG. 15 , showing components of the latch mechanism in place within the latch case, with the cable of the triggering device attached to the latch; [0085] FIG. 21 is an exploded longitudinal cut-away perspective view of the latch mechanism of FIG. 20 ; [0086] FIG. 22 is a further exploded longitudinal perspective view of the latch mechanism of FIG. 20 , with the post of the latch mechanism cut-away through its center; [0087] FIG. 23 is an exploded transverse cut-away perspective view of the latch mechanism of FIG. 20 ; [0088] FIG. 24 is a view of a pack according to the invention having a readily burstable slide fastener, rather than a non-locking closure for the airbag; [0089] FIG. 25 is a view of the pack of FIG. 24 , showing the airbag in a deployed and inflated position; [0090] FIG. 26 is an exploded perspective view of the handle, base, cable, and rotatable safety lock components of the triggering device shown in FIG. 19 ; [0091] FIG. 26A is a top view of the components of FIG. 26 , with the rotatable safety lock in the unlocked position; [0092] FIG. 26B is a longitudinal cross-sectional view taken along lines A-A of FIG. 26A ; [0093] FIG. 26C is an enlarged detail of FIG. 26B ; [0094] FIG. 27 is a perspective view of the handle, base, cable, and rotatable safety lock components of the triggering device shown in FIG. 19 , assembled in the locked position of the lock; [0095] FIG. 27A is a top view of the components of FIG. 27 , with the rotatable safety lock in the locked position; [0096] FIG. 27B is a longitudinal cross-sectional view taken along lines A-A of FIG. 27A ; [0097] FIG. 27C is an enlarged detail of FIG. 27B ; [0098] FIG. 28 is a perspective view of the handle, base, cable, and rotatable safety lock components of the triggering device shown in FIG. 19 , assembled in a “pulled” position of the trigger handle, that is, in the airbag-inflation-initiation position; [0099] FIG. 28A is a top view of the components of FIG. 28 ; [0100] FIG. 28B is a longitudinal cross-sectional view taken along lines A-A of FIG. 28A ; and [0101] FIG. 28C is an enlarged detail of FIG. 28B . DETAILED DESCRIPTION [0102] The following description makes reference to FIGS. 1-28C , which illustrate exemplary embodiments and features of the invention. The description and drawings are presented for the purpose of explanation and understanding, but the particular structures, details, and features that are shown and described are not intended to limit the invention unless otherwise expressed herein. [0103] The invention encompasses a triggering device, such as for use in an avalanche rescue system, and, more particularly, in a system that employs a backpack or harness that carries an inflatable airbag. A triggering device according to the invention includes structural components designed to initiate the activation of the means used to inflate the airbag, such as an electric motor that turns a fan/turbine/impeller or that activates inflation via a compressed gas or air canister/cartridge/container. [0104] FIG. 1 illustrates a pack 1 worn on the back of a user, the pack being supported by at least one shoulder strap 2 , or a pair of shoulder straps 2 , 2 ′, one of which is shown in FIG. 1 . In the embodiment shown in FIG. 1 , the top of the pack includes a hinged lid 3 , shown in a closed position beneath which an uninflated or underinflated airbag, or balloon, is housed within a compartment of the pack 1 . The top of the pack can be designed differently, such that, for example, the pack is closed by means of a structural configuration that utilizes a mechanical latch or no latch. As described in greater detail below with reference to other drawing figures, once the user activates the triggering device, the latch is moved to a position that allows the stowed airbag to emerge from within the pack as it is inflated. As also described below, alternatively, an airbag compartment can be closed with a readily burstable slide fastener, such as a burst zipper, which opens from the force of the inflating airbag. [0105] The trigger handle 4 of the triggering device 30 , described in greater detail below and with reference to additional drawing figures (see FIG. 4 , for example), is shown in FIG. 1 in the non-airbag-inflation-initiation position. According to the invention, the triggering handle 4 is designed to be easily accessible to the user, no pocket or cover designed to stow it away, but being difficult to trigger accidentally. A cable 5 or, more particularly, a cable in a housing 36 , extends from the triggering handle 4 to an actuator that activates inflation of the airbag. This actuator can be coupled to a latch, as further described below. [0106] For example, the trigger handle 4 is constantly available on, or just off, a shoulder strap and not, for example, in a closed pocket, perhaps zipped away. FIG. 1 shows the trigger handle 4 conveniently located at a generally mid-torso height, or slightly above the mid-torso, and at a left-of-center position on or proximate the left shoulder strap, the latter location being particularly convenient for grasping the handle with the right hand. For left-handed grasping of the trigger handle, the trigger handle is releasably fixed in placed so that it can be relocated on or proximate the right shoulder strap. As shown in FIG. 1 , the trigger handle 4 is constantly available. [0107] FIG. 2 is a front view of a pack 1 ′ according to the invention, having a trigger handle 6 with a shape different from that of the trigger handle 4 of FIG. 1 . The trigger handle 6 is shown in an unlocked position (indicated by a solid circle on the lock 12 ′) and in a locked position (indicated by an “X” on the lock 12 ′). The pack of FIG. 2 shows an optional waist belt 7 for additional support on the wearer, as well as a leg strap 8 , both of which can be employed in the pack of FIG. 1 . [0108] In addition, sternum strap 9 extends between the left and right shoulder straps 2 , 2 ′. An optional feature of the invention is a lanyard 10 , in the form of a cross-chest cable, as shown in FIGS. 3 and 4 , having one end fixed to the trigger handle 4 , such as through a hole 25 (see FIG. 14A ) or hole 25 ′ (see FIG. 26A ). In FIG. 3 , the opposite end of the lanyard 10 is releasably clipped to the left shoulder strap 2 , that is, the same shoulder strap to which the triggering device and trigger handle 4 is connected. In FIG. 4 , the releasable clip 11 is released from the right shoulder strap 2 and is secured to the left shoulder strap 2 ′. When the lanyard 10 is positioned to extend as shown in FIG. 4 , the user is provided with a supplemental triggering mechanism to provide additional triggering possibilities in the event access to the trigger handle 4 (or handle 6 of FIG. 2 ) were to be difficult in an avalanche situation. That is, in certain avalanche situations, when one is caught in an avalanche slide before the airbag can be triggered, it can become difficult or impossible to reach the trigger handle so as to pull and activate the airbag. In such a case, the wearer would have the option of swiping either hand downward along the torso between the shoulder straps and catch the lanyard 10 and pull it downward, thereby also pulling the trigger handle 4 or 6 downward to initiate airbag inflation. This supplemental triggering mechanism/lanyard thereby provides the possibility of accomplishing triggering of inflation of the airbag with a larger and less precise movement than grasping the trigger handle. Alternatively, the lanyard 10 , when not connected across the user's chest, can also be allowed to hang below the trigger handle such that it can be caught with a simple swipe of the thumb. Such lanyard can be used with either blower or compressed air or gas systems. In fact, according to the invention, a lanyard can be attached to any trigger for any airbag rescue system generally. This would include airbag rescue systems other than those disclosed herein, including such systems with or without safety locks, for example. Further, the releasable clip 11 can be any of many types, such as snap hooks, detachable buckles, and others. [0109] Accidental triggering is prevented by virtue of certain precautionary measures. First, a trigger lock is incorporated into the trigger handle 4 , 6 . FIGS. 5 and 6 schematically illustrate two respective positions of a first embodiment of the lock, in the form of a slide trigger lock 12 , retained in place by lock retainer 19 with fasteners 47 . This first embodiment and a second embodiment of such a lock are further described below and are illustrated in other drawing figures. The slide trigger lock 12 , similar to a gun safety, is easily moved by one's finger selectively between an engaged and locked position (shown in FIG. 5 ), and a disengaged and unlocked position (shown in FIG. 6 ), the trigger lock being secure and stable in each position. FIG. 18B also illustrates the trigger lock 12 in the locked (engaged) position, and FIG. 17B illustrates the trigger lock 12 in the unlocked (disengaged) position. These respective positions are visible to the user by virtue of the position of the slide trigger lock 12 in relation to the length of the remainder of the trigger handle 12 . More specifically, when the slide lock 12 is in the unlocked position, the width of the lock 12 is centered, or substantially centered, in relation to the length of the handle 12 , as shown in FIG. 17 . When the slide lock 12 is in the locked position, the width of the lock 12 is offset in relation to the length of the handle 6 , as shown in FIG. 18 . Still further, the cross-sectional enlarged detail views of FIGS. 17B and 18B show different engagements of surfaces of the base 13 slide lock in the unlocked and locked positions, respectively. In the unlocked slide lock position of FIG. 17B , the lower profile wedge 52 of the inside of the lock 12 is positioned in the recess, that is, detent recess 14 of the base 13 only partially and, when the user pulls on the handle along the base, the engagement between the handle 12 and base 13 is overcome upon exertion of a sufficient longitudinal pulling force, whereby the cable is pulled and inflation of the bag is initiated. If, however, the slide lock 12 were to be moved in its offset, locked, position of FIG. 18 , a wider profile wedge 53 comes into play, as shown in FIG. 18B , that has a shape that more fully engages the recess of the base, that is, the detent 14 of the base or, more specifically, the detent recess of the base. Herein, the expression “detent recess” is used to refer to a recess that is designed to be engaged with a detent or other wedge, projection, or surface. Such engagement effectively blocks, or at least effectively blocks, any effort by the user to pull the handle 12 longitudinally to an airbag-inflation-initiation position. The slide trigger lock 12 is also shown in the exploded diagrams of FIGS. 14 , 14 A, and 14 B. The slide trigger lock 12 , and a rotatable, or twistable, trigger lock 12 ′, are further described below. The invention encompasses airbag systems generally, including ones that rely upon a compressed air or gas cartridge, that have a triggering device that requires a pulling of a handle for actuation, inasmuch as such pulling can be provided to be locked against movement or unlocked for movement. [0110] A second measure to prevent accidental triggering is a requirement for a certain threshold force to be exerted for triggering the activation of the inflation of the airbag. For example, a pull force within a range of 50 N to 150 N, for example, can be set to release the airbag, i.e., a good firm pull. This range is in the proposed CE standard (such as in the February 2014 draft Norm prEN 16716 “Mountaineering equipment—Avalanche airbag systems—Safety requirements and test methods).” For example, a force of 100 N can be set. [0111] As shown in FIG. 6 , as well as in FIGS. 14 , 14 A, and 14 B, the trigger handle 4 is movable longitudinally in relation to the base 13 of the triggering device, the base 13 being fixed with respect to a base plate 15 , the base plate being fixed in relation to the shoulder strap 2 . The base 13 is raised from the surface of the shoulder strap and the interior of the trigger handle 4 slidably receives the longitudinally projecting base. The cable 5 extends from the pack through the base 13 and is fixed to the trigger handle 4 by means of a cable end stop 17 and a stopper 18 . On the outer surface of the base 13 is at least one detent recess 14 , although two additional detent recesses 14 ′ are shown in the drawing, which detents become frictionally engaged with an inner surface of the trigger handle 4 when the handle is pulled in a direction to trigger airbag inflation. The detent recess(es) 14 and 14 ′ and the interior of the handle 4 are structured and made of materials, such as one or more elastically deformable materials or shapes so as to require the aforementioned force of 50-150 N to be exerted by pulling on the trigger handle 4 , by means of the interior of the handle 4 passing over the detent recess 14 , the additional detent recesses 14 ′ providing a lesser force, yet providing physical feedback to the user. The required force 50-150 N could be settable and/or designed differently, for instance, by using elastic means, a spring, rubber, or the like. The total pull travel of the trigger handle 4 , 6 is approximately 45 to 50 mm in accordance with a non-limiting embodiment and beyond the frictional sliding of the handle over the detent recesses 14 , 14 ′, thereby providing an opportunity to stop pulling in the event of an unintentional triggering attempt. [0112] The foregoing description is also applicable to the second triggering device embodiment 30 ′ illustrated in exploded perspective in FIG. 19 , which includes handle 6 , lock 12 ′, lock retainer 19 ′, and base 13 ′. The handle 4 , as shown in FIGS. 14 , 14 A, 14 B, is comprised of front and rear parts secured together. Likewise, the handle 6 , shown in FIG. 19 , is comprised of front and rear parts 6 A, 6 B which are secured together by means of fasteners 47 . [0113] After the minimum pull force is reached and the trigger handle 4 , 6 has moved longitudinally beyond the base 13 or 13 ′, the handle can pivot and move at an indirect angle in relation to the length of attached cable 5 to cover multiple pull angles, as the handle 4 , 6 is then merely tethered to the shoulder strap 2 by means of the cable 5 . [0114] Next, the latch mechanism 20 , if used in any particular embodiment, and, for an electrically powered inflation embodiment, the triggering of a power switch 32 , that corresponds to the actuator that activates the airbag, are described with reference to relevant figures of the drawing. [0115] When a completed pull of the handle 4 or 6 is accomplished, the locking post 21 of the latch mechanism 20 (see FIGS. 10 and 16 , for example), fixed to the lid 3 at the top of the pack 1 , by means of fasteners 26 extending through the post plate 55 , and projecting downward from the lid, is pushed out of the latch 22 . The ramp 23 of the latch (see FIG. 16 , for example), as it is pulled by the cable 5 , ensures enough force so that the post 21 can be pushed out even in the event it had become frozen in place). An electrical switch 32 , fixed together with the latch 22 within the latch case comprised of the case top 28 and case bottom 29 (see FIGS. 15 and 16 , for example), is incorporated within the latch mechanism 20 such that the post 21 must be released from the latch 22 before the electric motor can be activated (see FIGS. 15 , 16 , for example) by means of the plunger 34 engaging the power switch 32 . FIG. 15 illustrates a surface plate 31 , mounted to the fabric of the pack 1 by means of fasteners 26 connecting the plate 31 to the latch case 28 , 29 , with the switch 32 and latch 22 positioned within the thusly mounted case. The compression spring 35 biases the latch 22 to return to its initial position within the latch case after separation of the post 21 and the latch 22 . [0116] The latch mechanism 20 of FIG. 16 also shows the cable housing 36 , a compression nut 37 against which a collet 40 is positioned, the nut being engaged with the threaded sections 38 , 38 ′ that are formed on the respective top and bottom 28 , 29 of the latch case. A protection tube 39 is provided for the electrical cable 41 to which the switch 32 is connected. The perspective and cross-sectional exploded views of FIGS. 20-23 show the latch mechanism 20 in greater detail. [0117] After the post 21 is clear of the hook 24 of the latch 22 (that is, nothing holding the airbag compartment within the pack 1 closed, as shown in FIGS. 9-13 ), the motor is powered on to inflate the airbag 33 , such as for a seven-second blower activation. That is, the motor cannot be activated until the post 21 has been released from the latch 22 . [0118] Once the latch 22 and post 21 of the latch mechanism 20 are released from each other, the lid 3 of the airbag compartment is completed unfettered to open (see FIGS. 9 , 10 ), such that the inflation of the airbag 33 itself forces it from the compartment of the pack 1 to a deployed position. The post/latch combination 21 , 22 is the single locking point of closure. The airbag 33 is stowed purely by being folded (such as by “origami” style or any non-restricting fold(s), but not by being rolled, for example), which allows the airbag to release, during inflation, in all directions (into a more than a full hemisphere), rather than “funneling” through a narrow door, for example. [0119] The releasable latching embodiment described above is not the only closure that is encompassed by the invention, inasmuch as a non-locking closure for the airbag can be employed. For example, a separating sliding fastener, such as a readily burstable slide fastener, such as a burst zipper 42 shown in FIG. 24 , can be employed. As known in the art, a burstable zipper has a number of teeth removed or omitted from one or more of the stringers of the zipper. If a burst zipper is employed, it can be positioned to extend across the top of the pack and, optionally, down the sides, as shown in FIG. 24 , as the airbag is inflating, whereby the burst zipper automatically opens from the force generated by the inflating airbag, thereby allowing the airbag to emerge from the airbag compartment to the deployed position shown in FIGS. 2B and 25 . The burst zipper can be re-zipped for further use, after the airbag is deflated and re-stowed in its compartment. With a readily burstable slide fastener, the cable system is used for activating the power switch 32 , there being no need to open a latching mechanism as well. Optionally, with the use of a burstable slide fastener, a Velcro® tab could be employed across the length of the fastener and it would be designed to release at the time of airbag inflation. [0120] Any time after inflation of the airbag, such as shown in FIGS. 2B and 25 , the trigger handle 4 or 6 can be pulled again to activate another seven-second blower cycle, or a cycle having an appropriate duration for a given application. In addition, upon inflation of the airbag and deployment during use, the blower can be automatically pulsed repeatedly to maintain inflation or a predetermined level of inflation. [0121] After having deployed the airbag, the airbag can be returned to the non-deployed position within the pack (as shown in FIGS. 2 , 2 A, and 24 ), the trigger handle 4 or 6 must be physically pushed back into the closed position, that is, in the non-airbag-inflation-initiation position (see FIG. 3 , showing the closed position, FIG. 4 showing the open position, that is, the airbag-inflation-initiation position) to re-enable the latching mechanism 20 , if used, for stowing the airbag in its compartment. This ensures that the latch 22 cannot be accidentally re-fastened to the post 21 . Alternatively, a detent recess can be provided within the switch/latch case 28 , 29 that holds the latch 22 in an open position once it has been deployed. The locking post 21 being forcefully re-inserted into the socket 43 (see FIG. 16 ) engages with the ejector ramp 23 on the latch plunger 34 and snaps the latch 22 back past the detent recess. In this way, the ramp is used to the exact opposite effect as when it is used to eject the post initially. The trigger handle 4 or 6 , in either event, is to be re-docked, if the cable length is set to do so, but it is not required. [0122] Once the airbag is deflated, that is, purged of air, it can be easily packed back into the compartment of the pack (origami-style, for example, or otherwise using non-restricting folds) and quickly latched securely. [0123] The cable mechanism, comprising the cable 5 extending between the trigger handle 4 or 6 and the latch mechanism 20 or burstable zipper 42 , at the top of the pack, as well as associated parts, such as the housing 36 , the compression nut 44 that engages with the threaded extension 46 attached to the flanged connector 16 , or retaining flange, and the collet 45 , is similar to the type of cable mechanism like that used in a bicycle brake cable system, for example. [0124] The latch mechanism 20 (post in keyhole) is a solid structural component when closed (see FIGS. 7 , 8 , and 9 ) and is the only closure point on the compartment containing the airbag. The sides of the airbag compartment are folded in and are secured along with the top of the compartment at the latch point (see FIG. 11 ). [0125] Features of the invention, relating to the foregoing description, include the following: An easily accessible exposed handle with a secure yet easily operated safety lock; Travel of the trigger handle over one or more detent recesses for additional warning of impending activation; Action at end of travel of the trigger handle to ensure a mechanical failsafe for proper sequence to (1) release the latch and (2) power on the motor; mechanical release also ensures release in wet, cold, icy conditions; Inability to re-latch without first repositioning the trigger handle; Clippable lanyard to provide additional activation surface in difficult situations; Airbag compartment folded so that it has a single latch point and, once unlatched, is completely free to open in any direction (except where it is attached to the pack). [0133] In an alternative embodiment (not shown), the airbag compartment and the latch mechanism are different. The opening is on the upper back side of the pack top, that is, away from the wearer and in about the same orientation as in FIGS. 7 and 13 but facing the other way. It is secured by a hook-and-loop fastener, rather than the latch mechanism extending through holes in the fabric, as in the illustrated embodiment described above. In such a version, the cable runs over the top of the pack and allows the wearer to pull the hook-and-loop fastener open with the cable. It also features a switch for the motor that cannot be activated until the fastener has been opened. [0134] A particular feature of the triggering handle 4 or 6 is that it is very easy for the user, that is, the person wearing the avalanche airbag and pack, to locate and grab the handle. To this end, the handle is always externally accessible, in contrast to systems whose components are stowed in a pouch, such as a zippered pouch, on a shoulder strap to prevent an accidental release that might be caused by being caught/snagged on something or an ill-timed or accidental manipulation. For systems in which the handle is kept in a pouch, the user can forget to unzip the handle and have it accessible when it is taken out. Also, they tend to move around within the pouch, so the handle is not in the same position all the time. [0135] As mentioned above, the triggering device of the invention includes at least two features to avoid accidental triggering, while maintaining the triggering handle permanently exposed and easily accessible. One is that which is described above that includes the detent recess 14 , particularly, over which the trigger handle 4 or 6 is engaged as the handle is pulled and a force of 50-150 N is required to completely pull the trigger handle for triggering activation. [0136] The second feature relates to a safety lock mechanism, such as that which includes a slidable lock 12 illustrated in FIGS. 17 , 17 A, 17 B (unlocked) and FIGS. 18 , 18 A, 18 B (locked). The slide lock 12 is designed to be moved between locked and unlocked positions with a single finger or thumb. In an emergency situation, the user might want to have the handle unlocked in a critical area. The motion that is required to unlock the slide lock safety triggering device is similar to that required for a gun safety lock. The locking mechanism is simply movable transversely, with a snap action, between the locked and unlocked positions. [0137] The second feature can be realized differently, by a second embodiment of a pack 1 ′ as illustrated in FIGS. 26 , 26 A, 26 B, and 26 C. The triggering device 30 ′ has an alternative safety lock mechanism, particularly, one having a twistable lock 12 ′, rather than a slide lock, that is, a lock that is rotatable about the base 13 ′ that allows the user to flip the lock 180 degrees, i.e., with the remainder of the handle, around the base between locked and unlocked positions, the latter position allowing the handle 6 to be pulled longitudinally to initiate airbag inflation. That is, for accomplishing airbag inflation, the user moves the triggering device according to two manipulations. First, the safety lock 12 ′ must be rotated from the locked position (shown in FIGS. 27 and 27A ) to the unlocked position (shown in FIG. 26A ). Second, the trigger handle 6 must be pulled in relation to the base 13 ′ to the position shown in FIGS. 28 , 28 A, and 28 B. FIG. 28C illustrates an enlarged detail of FIG. 28B , showing the trigger handle stopper 18 having reached a restricted position in relation to the trigger handle 6 such that the stopper 18 , secured in place by the wire cable 5 end stop 17 to thereby release the post 21 from the latch 22 , for embodiments having both a latch mechanism 20 (see FIG. 16 , for example) and actuating the electrical switch 32 , as explained above. [0138] In the unlocked position of the twist lock 12 ′, whereby the handle 6 had been twisted 180° around the base 13 ′, a lower profile wedge 48 projecting from the interior of the handle 6 , shown in FIG. 26C , provides a certain level of resistance, such as within the range of 50-150 N, for disengagement of the lock from the detent recess 14 during the pulling of the handle 6 to the pulled position shown in FIG. 28 . An indication on the handle 6 , in the form of a green circle 51 , alerts the user to the handle being in the unlocked position. Other forms and shapes can be used for the same purpose. [0139] A red “X” 50 , or other indication, is shown in FIGS. 27 and 27B as an indication that the handle 6 is in the locked position, after the handle had been rotated from the unlocked position. As shown in FIG. 27C , the higher profile wedge 49 of the handle 6 provides a positive lock against longitudinal displacement of the handle 6 in the locked position. While the detent recess 14 is shown on the base 13 ′ (or base 13 , for the slide lock embodiment), the detent recess could be located on the handle and a complementary wedge or projection could be formed on the base. [0140] The aforementioned locked and unlocked positions of the “twist” trigger handle 6 are also indicated in FIG. 2 , with an “X” and “O”, respectively, for the two positions of the safety lock 12 ′. In this example, the indication of the state of the handle (locked or unlocked) is visible, which means this indication is not oriented toward the user, but outwardly. [0141] The triggering device 30 , 30 ′ can also comprise means for maintaining the trigger lock 12 , 12 ′ in an expected position, locked/unlocked. These means may be clips, plastic deformation, tightening, for example. [0142] For manufacturing airbag rescue systems and triggering devices in particular, the use of various materials are within the scope of the invention and various manufacturing processes are within the scope of the invention, such as injection molding. Various components of the triggering device, such as the handle and the lock, as well as the base, for example, can be made of any of various synthetic polymers such as particular thermoplastics, including nylon and, more particularly, polyoxymethylene (POM), for example, the latter being self-lubricating and offers favorable characteristics for use in cold and wet conditions, has a low coefficient of friction, low water absorption, excellent dimensional stability, and high tensile strength, for example. In this regard, variations of components are embraced by the invention, such as making the base plate 15 and retaining flange 16 as one piece. Other components, such as cables, screws, nuts, etc. can be made of stainless steel or other materials that have characteristics that perform well in outdoor environments, particularly in wet and cold environments. [0143] The invention is not limited to the particular embodiments shown and described, but extends to all embodiments covered by the following claims. [0144] Lastly, at least because the invention is disclosed herein in a manner that enables one to make and use it by virtue of the disclosure of particular exemplary embodiments of the invention, the invention can be practiced in the absence of any additional element or additional structure that is not specifically disclosed herein.
An airbag rescue system employed as a life-saving system to enable a person to survive an avalanche or other situation, such as a water rescue. The airbag system includes an air movement device that takes the form of a source of compressed air or an electrically powered air mover, such as one that includes a bladed rotor for inflating the airbag with ambient air, such as 100% ambient air, for example. The system further includes a supporting device, such as a harness or a backpack, for supporting the inflatable airbag and the powered air movement device on a user in a ready position of the airbag rescue system. The system also includes triggering device that includes a trigger handle configured and arranged to initiate inflation of the inflatable airbag by being manipulated by the user. In the ready position of the airbag rescue system, while the airbag is not yet in a deployed position, the trigger handle is conveniently externally accessible for the user to trigger the inflation of the airbag.
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FIELD OF INVENTION [0001] This invention relates generally to the field of video analysis and indexing, and more particularly to video event detection and indexing. BACKGROUND OF THE INVENTION [0002] Current video indexing systems are yet to bridge the gap between low-level features and high-level semantics such as events. A very common and general approach relies heavily on shot-level segmentation. The steps involve segmenting a video into shots, extracting key frames from each shot, grouping them into scenes, and representing them using hierarchical tress and graphs such as scene transition graphs. However since accurate shot segmentation remains a challenging problem (analogous to object segmentation for still images), there is a mismatch between low-level information and high-level semantics. [0003] Other video indexing systems tend to engineer the analysis process with very specific domain knowledge to achieve more accurate object or/and event recognition. The kind of highly domain-dependent approach makes the production process and resulting system very much ad-hoc and not reusable even for a similar domain (e.g. another type of sports video). [0004] Most event detection methods in sports video are based on visual features. However, audio is also a significant part of sports video. In fact, some audio information in sports video plays an important role in semantic event detection. Compared with research done on sports video analysis using visual information, very little work has been done on sports video analysis using audio information. A speech analysis approach to detect American football touchdowns has been suggested. Actual keywords, spotting and cheering detection were applied to locate meaningful segments of video. Vision-based line-mark and goal-posts detection were used to verify the results obtained from audio analysis. Another proposed solution is to extract highlights from TV baseball programs using audio-track features alone. To deal with an extremely complex audio track, a speech endpoint detection technique in noisy environment was developed and support vector machines were applied to excited speech classification. A combination of generic sports features and baseball-specific features were used to detect the specific events. [0005] Another proposed approach is to detect a cheering event in a basketball video game using audio features. A hybrid method was employed to incorporate both spectral and temporal features. Another proposed method to summarizes sports video using pure audio analysis. The audio amplitude was assumed to reflect the noise level exhibited by the commentator and was used as a basis for summarization. These methods tried to detect semantic events in sports video directly based on low-level features. However, in most sports videos, low-level features cannot effectively represent and infer high-level semantics. [0006] Published US Patent Application US 2002/0018594 A1 describes a method and system for high-level structure analysis and event detection from domain-specific videos. Based on domain knowledge, low-level frame-based features are selected and extracted from a video. A label is associated with each frame according to the measured amount of the dominant feature, thus forming multiple frame-label sequences for the video. [0007] According to Published EP Patent Application EP 1170679 A2, a given feature such as color, motion, and audio, dynamic clustering (i.e. a form of unsupervised learning) is used to label each frame. Views (e.g. global view, zoom-in view, or close-up view in a soccer video) in the video are then identified according to the frame labels, and the video is segmented into actions (play-break in soccer) according to the views. Note that a view is associated with a particular frame based on the amount of the dominant color. Label sequences as well as their time alignment relationship and transitional relations of the labels are analyzed to identify events in the video. [0008] The labels proposed in US 2002/0018594 A1 and EP 1170679 A2 are derived from a single dominant feature of each frame through unsupervised learning, thus resulting in relatively simple and non-meaningful semantics (e.g. Red, Green, Blue for color-based labels, Medium and Fast for motion-based labels, and Noisy and Loud for audio-based labels). [0009] Published US Patent U.S. Pat. No. 6,195,458 B1 proposes to identify within the video sequence a plurality of type-specific temporal segments using a plurality of type-specific detectors. Although type-related information and mechanism are deployed, the objective is to perform shot segmentation and not event detection. SUMMARY OF THE INVENTION [0010] In accordance with a first aspect of the present invention there is provided a method for use in indexing video footage, the video footage comprising an image signal and a corresponding audio signal relating to the image signals, the method comprising extracting audio features from the audio signal of the video footage and visual features from the image signal of the video footage; comparing the extracted audio and visual features with predetermined audio and visual keywords; identifying the audio and visual keywords associated with the video footage based on the comparison of the extracted video and visual features with the predetermine audio and visual keywords; and determining the presence of events in the video footage based on the audio and visual keywords associated with the video footage. The method may further comprise partitioning the image signal and the audio signal into visual and audio sequences, respectively, prior to extracting the audio and visual features therefrom. [0011] The audio sequences may overlap. The visual sequences may overlap. [0012] The partitioning of visual and audio sequences may be based on shot segmentation or using a sliding window of fixed or variable lengths. [0013] The audio and visual features may be extracted to characterize audio and visual sequences, respectively. [0014] The extracted visual features may include one or more of measures related to motion, color, texture, shape, and outcome of region segmentation, object recognition, and text recognition. [0015] The extracted audio features may include one or more of measures related to linear prediction coefficients (LPC), zero crossing rates (ZCR), mel-frequency cepstral coefficients (MFCC), and spectral power. [0016] To effect the comparison, relationships between audio and visual features and audio and visual keywords may be previously established. [0017] The relationships may be previously established via machine learning methods. The machine learning methods used to establish the relationships may be unsupervised, using preferably any one or more of: c-means clustering, fuzzy c-means clustering, mean shift, graphical models such as an expectation-maximization algorithm, and self-organizing maps. [0018] The machine learning methods used to establish the relationships may be supervised, using preferably any one or more of: decision trees, instance-based learning, neural networks, support vector machines, and graphical models. [0019] The determining of the presence of events in the video footage may comprise detecting video events according to a predefined set of events based on a probabilistic or fuzzy profile of the audio and video keywords. [0020] To effect the determination, relationships between the audio and visual keyword profiles and the video events may be previously established. [0021] The relationships between the audio and visual keyword profiles and the video events may be previously established via machine learning methods. [0022] The machine learning methods used to establish the relationships between audio-visual keyword profiles and video events may be probabilistic-based. The machine learning methods may use graphical models. [0023] The machine learning methods used may be techniques from syntactic pattern recognition, preferably using attribute graphs or stochastic grammars. [0024] The extracted visual features may be compared with visual keywords and extracted audio features are compared with audio keywords independently of each other. [0025] The extracted audio and visual features may be compared in a synchronized manner with respect to a single set of audio-visual keywords. [0026] The method may further comprise normalizing and reconciling the outcome of the results of the comparison between the extracted features and the audio and visual keywords into a probabilistic or fuzzy profile. [0027] The normalization of the outcome of the comparison may be probabilistic. [0028] The normalization of the outcome of the comparison may use the soft max function. [0029] The normalization of the outcome of the comparison may be fuzzy, preferably using the fuzzy membership function. [0030] The outcome of the results of the comparison between the extracted features and the audio and visual keywords may be distance-based or similarity-based. [0031] The method may further comprise transforming the outcome of determining the presence of events into a meta-data format, binary or ASCII, suitable for retrieval. [0032] In accordance with a second aspect of the present invention there is provided a system for indexing video footage, the video footage comprising an image signal and a corresponding audio signal relating to the image signals, the system comprising means for extracting audio features from the audio signal of the video footage and visual features from the image signal of the video footage; means for comparing the extracted audio and visual features with predetermined audio and visual keywords; means for identifying the audio and visual keywords associated with the video footage based on the comparison of the extracted video and visual features with the predetermine audio and visual keywords; and means for determining the presence of events in the video footage based on the audio and visual keywords associated with the video footage. BRIEF DESCRIPTION OF THE DRAWINGS [0033] FIG. 1 is a schematic diagram to illustrate key components and flow of the video event indexing method of an embodiment. [0034] FIG. 2 depicts a three-layer processing architecture for video event detection based on audio and visual keywords according to an example embodiment. [0035] FIGS. 3A to 3F show key frames of some visual keywords for soccer video event detection. [0036] FIG. 4 shows a flow diagram for static visual keywords labeling in an example embodiment. [0037] FIG. 5 is a schematic drawing illustrating break portions extraction in an example embodiment. [0038] FIG. 6 is a schematic drawing illustrating a computer system for implementing the method and system in an example embodiment. DETAILED DESCRIPTION OF THE INVENTION [0039] A described embodiment of the invention provides a method and system for video event indexing via intermediate video semantics referred to as audio-visual keywords. FIG. 1 illustrates key components and flow of the embodiment as a schematic diagram. [0040] The audio and video tracks of a video 100 are first partitioned at step 102 into small segments. Each segment can be of (possibly overlapping) fixed or variable lengths. For fixed length, the audio signals and image frames are grouped by fixed window size. Typically, a window size of 100 ms to 1 sec is applied to audio track and a window size of 1 sec to 10 sec is applied to the video track. Alternatively, the system can perform audio and video (shot) segmentation. In case of audio segmentation, the system may e.g. make a cut when the magnitude of the volume is relatively low, for audio shot segmentation. For video segmentation, shot boundaries can be detected using visual cues such as color histograms, intensity profiles, motion changes, etc. [0041] Once an audio or video tracks have been segmented at step 102 , suitable audio and visual features are extracted at steps 104 and 106 respectively. For audio, features such as linear prediction coefficients (LPC), zero crossing rates (ZCR), mel-frequency cepstral coefficients (MFCC), and spectral power are extracted. For video, features related to motion vectors, colors, texture, and shape are extracted. While motion features can be used to characterize motion activities over all or some frames in the video segment, other features may be extracted from one or more key frames, for instance first, middle or last frames, or based on some visual criteria such as the presence of a specific object, etc. The visual features could also be computed upon spatial tessellation (e.g. 3×3 grids) to capture locality information. Besides low level features as just described, high-level features related to object recognition (e.g. faces, ball etc) could also be adopted. [0042] The extracted audio and video features of the respective audio and video segments are compared at steps 108 and 110 respectively to compatible (same dimensionality and types) features of audio and visual “keywords” 112 and 114 respectively. “Keywords” as used in the description of the example embodiments and the claims refers to classifiers that represent a meaningful classification associated with one or a group of audio and visual features learned beforehand using appropriate distance or similarity measures. The audio and visual keywords in the example embodiment are consistent spatial-temporal patterns that tend to recur in a single video content or occur in different video contents where the subject matter is similar (e.g. different soccer games, baseball games, etc.) with meaningful interpretation. Examples of audio keywords include: a whistling sound by a referee in a soccer video, a pitching sound in a baseball video, the sound of a gun shooting or an explosion in a news story, the sound of insects in a science documentary, and shouting in a surveillance video etc. Similarly, visual keywords may include those such as: an attack scene near the penalty area in a soccer video, a view of scoreboard in a baseball video, a scene of a riot or exploding building in a news story, a volcano eruption scene in a documentary video, and a struggling scene in a surveillance video etc. [0043] In the example embodiment, learning of the mapping between audio features and audio keywords and between visual features and visual keywords can be either supervised or unsupervised or both. For supervised learning, methods such as (but not limited to) decision trees, instance-based learning, neural networks, support vector machines, etc. can be deployed. If unsupervised learning is used, algorithms such as (but not limited to) c-means clustering, fuzzy c-means clustering, expectation-maximization algorithm, self-organizing maps, etc. can be considered. [0044] The outcome of the comparison at steps 108 and 110 between audio and visual features and audio and visual keywords may require post-processing at step 116 . One type of post-processing in an example embodiment involves normalizing the outcome of comparison into a probabilistic or fuzzy audio-visual keyword profile. Another form of post-processing may synchronize or reconcile independent and incompatible outcomes of the comparison that result from different window sizes used in partitioning. [0045] The post-processed outcomes of audio-visual keyword detection serve as input to video event models 120 to perform video event detection at step 118 in the example embodiment. These outcomes profile the presence of audio-visual keywords and preserve the inevitable uncertainties that are inherent in realistic complex video data. The video event models 120 are computational models such as (but limited to) Bayesian networks, Hidden Markov models, probabilistic grammars (statistical parsing) etc as long as learning mechanisms are available to capture the mapping between the soft presence of the defined audio-visual keywords and the targeted events to be detected and indexed 122 . The results of video event detection are transformed into a suitable form of meta-data, either in binary or ASCII format, for future retrieval, in the example embodiment. [0046] An example embodiment of the invention entails the following systematic steps to build a system for video event detection and indexing: 1. The video events to be detected and indexed are defined; 2. The audio and visual keywords that are considered relevant to the spatio-temporal makeup of the events are identified. 3. The audio and visual features that are likely to be useful for the detection of the audio-visual keywords, that is those that are likely to correspond to such audio and visual keywords, are selected; 4. The mechanism to extract these audio and visual features from video data, in a compressed or uncompressed format, is determined and implemented. The mechanism also has the ability to partition the video data into appropriate segments for extracting the audio and visual features; 5. The mechanism to associate audio and visual features extracted from segmented video and the audio and visual keywords obtained from training data, based on supervised or unsupervised learning or both, is determined and implemented. The mechanism may include automatic feature selection or weighting. 6. The mechanism to map the audio and visual keywords to the video events, based on statistical or syntactical pattern recognition or both, is determined and implemented. The post-processing mechanism to normalize or synchronize the detection outcome of the audio and visual keywords is also included; 7. The training of the audio and visual keyword detection using the extracted audio and visual features is carried out and the computer representation of these audio-visual keyword detectors is saved. This is the actual machine learning step based on the learning model determined in step 5 ; 8. The training of video event detection using the outcome of the audio and visual detectors is carried out and the computer representation of these video event detectors is saved. This step carries out the recognition process as dictated by step 6 . [0055] The above steps in the example embodiment provide a V-shape process: top-down then bottom-up. The successful execution of the above steps results in an operational event detection system as depicted in FIG. 1 , ready to perform detection and indexing of video events. A schematic diagram illustrating the processing architecture for video event detection is shown in FIG. 2 , for the example embodiment. There are 3 layers: features 300 , audio and visual keywords (AVK) 302 , and events 304 . Features extracted from video segments are fed into learned models (indicated at 306 ) of AVK 302 where matching of video features and model features may take place and other decision making steps. Computational models such as probabilistic mapping (indicated at 308 ) are then used between the AVK 302 and events 304 . [0056] To illustrate the example embodiment further, an example processing based on a soccer video is described below with reference to FIGS. 3 to 5 . [0057] A set of visual keywords are defined for soccer videos. From the focus of the camera and the moving status of the camera point of views, the visual keywords are classified into two categories: static visual keywords (Table 1) and dynamic visual keywords (Table 2). [0000] TABLE 1 Static visual keywords defined for soccer videos Keywords Abbreviation Far view of whole field FW Far view of half field FH Far view of audience FA View from behind the goal GP post Mid range view (whole MW body visible) Close-up view (inside field) IF Close-up view (edge field) EF Close-up view (outside OF field) [0058] FIGS. 3A to 3F show the key frames of some exemplary static visual keywords, respectively: far view of audience, far view of whole field, far view of half field, view from behind the goal post, close up view (inside field), and mid range view. [0059] Generally, “far view” indicates that the game is playing and no special event happens so the camera captures the field from far to show the whole status of the game. “Mid range view” typically indicates the potential defense and attack so that the camera captures players and ball to follow the actions closely. “Close-up view” indicates that the game might be paused due to the foul or the events like goal, corner-kick etc so that camera captures the players closely to follow their emotions and actions. [0000] TABLE 2 Dynamic visual keywords defined for soccer videos Keywords Abbreviation Still camera ST Moving camera MV Fast moving FM camera [0060] In essence, dynamic visual keywords based on motion features in the example embodiment intend to describe the camera's motion. Generally, if the game is in play, the camera always follows the ball. If the game is in break, the camera tends to capture the people in the game. Hence, if the camera moves very fast, it indicates that either the ball is moving very fast or the players are running. For example: given a “far view” video segment, if the camera is moving, it indicates that the game is playing and the camera is following the ball; if the camera is not moving, it indicates that the ball is static or moving slowly which might indicate the preparation stage before the free-kick or corner-kick in which the camera tries to capture the distribution of the players from far. [0061] Three audio keywords are defined for the example embodiment: “Plain” (“P”), “Exciting” (“EX”) and “Very Exciting” (“VE”) for soccer videos. For a description of one technique for the extraction of the audio keywords, reference is made to Kongwah Wan and Changsheng Xu, “Efficient Multimodal Features for Automatic Soccer Highlight Generation”, in Proceedings of International Conference on Pattern Recognition (ICPR 2004), 4-Volume Set, 23-26 Aug. 2004, Cambridge, UK. IEEE Computer Society, ISBN 0-7695-2128-2, pp. 973-976, the contents of which are hereby incorporated by cross-reference. [0062] For the first step of processing in the example embodiment, conventional shot partitioning using a colour histogram approach to the video stream to segment video stream into video shots is performed. Then, shot boundaries are inserted within shots whose length is longer than 100 frames to further segment the shot into shorter segments evenly. For instance, a 150-frame shot will be further segmented into 2 video segments, 75-frame each. In the end, each video segment is labeled with one static visual keyword, one dynamic visual keyword and one audio keyword. With reference to FIG. 4 , for static visual keyword classification, first all the P-Frames 400 in the video segment are converted into edge-based binary maps at step 402 by setting all the edge points into white points and other points into black points. Also, all the P-Frames 400 are converted into color-based binary maps at step 404 by mapping all the dominant color points into black points and non-dominant color points into white points. Then, the playing field area is detected at step 406 and the Regions of Interest (ROIs) within the playing field area are segmented at step 408 . Finally, two support vector machine classifiers and some decision rules are applied to the position of the playing field and the properties of the ROIs such as size, position, texture ratio, etc at step 410 to label each P-Frame with one static visual keyword at step 412 . [0063] Each P-Frame 400 of the video segment is labeled with one static visual keyword in the example embodiment. Then, the static visual keyword that is labeled to the majority of P-frames is taken as the static visual keyword labeled to the whole video segment. For details of the classification of static visual keywords reference is made toYu-Lin Kang, Joo-Hwee Lim, Qi Tian, Mohan S. Kankanhalli, Chang-Sheng Xu, “Visual Keywords Labeling in Soccer Video”, in Proceedings of Int. Conf. on Pattern Recognition (ICPR 2004), 4-Volume Set, 23-26 Aug. 2004, Cambridge, UK. IEEE Computer Society, ISBN 0-7695-2128-2, pp. 850-853, the contents of which are hereby incorporated by cross-reference. [0064] Similarly, by calculating the mean and standard deviation of the number of motion vectors within different direction regions and the average magnitude of all the motion vectors, each video segment is labeled with one dynamic visual keyword in the example embodiment. [0065] For the audio keywords, the audio stream is segmented into audio segments of same intervals. Next, the pitch and the excitement intensity of the audio signal within each audio segment are calculated. Then, since the length of the audio segment is typically much shorter than the average length of the video segments, the video segment is used as the basic segment and the average excitement intensity of the audio segments within each video segment is calculated. In the end, each video segment is labeled with one audio keyword according to the average excitement intensity of the video segment. [0066] In the example embodiment a statistical model is used for event detection. More precisely, Hidden Markov Models (HMM) are applied to AVK sequences in order to detect the goal event automatically. The AVK sequences that follow the goal events share similar AVK pattern. Generally, after the goal, the game will pause for a while (around 30-60 seconds). During that break period, the camera may first zooms into the players to capture their emotions and people cheer for the goal. Next, two to three slow motion replays may be presented to show the actions of the goalkeeper and shooter to the audience again. Then, the focus of the camera might go back to the field to show the exciting emotion of the players again for several seconds. In the end, the game resumes. [0067] Generally, a long “far view” segment indicates that the game is in play and a short “far view” segment is sometimes used during a break. With reference to FIG. 5 , play portions are extracted in the example embodiment by detecting four or more consecutive “far view” video segments e.g. 500 . For break portions e.g. 502 , the static visual keyword sequence is scanned from the beginning to the end sequentially. When a “far view” segment, e.g. 504 is spotted in the brake portion 502 , a portion that starts from the first non-“far view” segment 506 thereafter and ending at the start of the next play portion is extracted and regarded as a break portion 508 . [0068] After break portions extraction, audio keywords are used to further extract exciting break portions. For each break portion, the number of “EX” and “VE” keywords that are labeled to the break portions are computed, denoted as EX num and VE num . The excitement intensity and excitement intensity ratio of this break portion is computed as: [0000] Excitement=2 ×VE num +EX num   (1) [0000] Ratio = Excitement Length ( 2 ) [0000] where Length is the number of the video segments within the break portion. [0069] By setting thresholds for excitement intensity ratio (T ratio ) and excitement intensity (T Excitement ) respectively, the exciting break portions are extracted. [0070] For each video segment, one static visual keyword, one dynamic visual keyword and one audio keyword are labeled in the example embodiment. Including the length of the video segment, a 13-dimensions feature vector is used to represent one video segment. Defining 12 AVKs in total, the first 12-dimensions correspond to the 12 AVKs. Given a video segment, only the dimensions that correspond to the AVKs labeled to the video segment are set to one and, other dimensions are all set to zero. The last dimension is used to describe the length of the video segment by a number between zero and one, which is the normalized version of the number of the frames of the video segment. [0071] Hidden Markov Model is used for analyzing the sequential data in the example embodiment. Two five-state left-right HMMs are used to model the exciting break portions with goal event (goal model) and without goal event (non-goal model) respectively. Goal model likelihood is denoted with G and non-goal model likelihood with N hereafter. Observations sent to HMMs are modeled as single Gaussians in the example embodiment. [0072] In practice, HTK is used for HMM modeling. Reference is made to S. Young, G. Evermann, D. Kershaw, G. Moore, J Odell, D. Ollason, D. Povey, V. Valtchev and P. Woodland, “ The HTK book” version 3.2 , CUED, Speech Group, 2002, the contents of which are hereby incorporated by cross-reference. The initial values of the parameters of the HMMs are estimated by repeatedly using Viterbi alignment to segment the training observations and then recomputing the parameters by pooling the vectors in each segment. Then, Baum-Welch algorithm is used to re-estimate the parameters of the HMMs. For each exciting break portion, we evaluate its feature vector likelihood under both two HMMs and we say the goal event is spotted within this exciting break portion if its G is bigger than its N. [0073] Six half matches of the soccer video (270 minutes, 15 goals) from FIFA 2002 and UEFA 2002 are used in an example embodiment. The soccer videos are all in MPEG-1 format, 352×288 pixels, 25 frames/second. [0074] AVK sequences of four half matches are labeled automatically. Since these four half matches have 9 goals only, we manually label two more AVK sequences of two half matches with 6 goals. For the purpose of cross validation, for each one of the four automatically labeled AVK sequences, the other five AVK sequences are used as training data to detect goal event from current AVK sequence. [0075] Exciting break portions are extracted from all the six AVK sequences automatically by different sets of threshold settings. In the example embodiment, best performance was achieved when the thresholds of T Ratio and T Excitement are set to 0.4 and 9 respectively (Table 3). [0000] TABLE 3 Result for goal detection (T Ratio = 0.4, T Excitement = 9) Video Goal Correct Miss False Alarm Precision Recall GER vs 3 3 0 0 100% 100% ENG LEV vs LIV 4 4 0 0 100% 100% LIV vs LEV 1 1 0 0 100% 100% USA vs 1 1 0 1  50% 100% GER Total 9 9 0 1  90% 100% [0076] The method and system of the example embodiment can be implemented on a computer system 800 , schematically shown in FIG. 6 . It may be implemented as software, such as a computer program being executed within the computer system 800 , and instructing the computer system 800 to conduct the method of the example embodiment. [0077] The computer system 800 comprises a computer module 802 , input modules such as a keyboard 804 and mouse 806 and a plurality of output devices such as a display 808 , and printer 810 . [0078] The computer module 802 is connected to a computer network 812 via a suitable transceiver device 814 , to enable access to e.g. the Internet or other network systems such as Local Area Network (LAN) or Wide Area Network (WAN). [0079] The computer module 802 in the example includes a processor 818 , a Random Access Memory (RAM) 820 and a Read Only Memory (ROM) 822 . The computer module 802 also includes a number of Input/Output (I/O) interfaces, for example I/O interface 824 to the display 808 , and I/O interface 826 to the keyboard 804 . [0080] The components of the computer module 802 typically communicate via an interconnected bus 828 and in a manner known to the person skilled in the relevant art. [0081] The application program is typically supplied to the user of the computer system 800 encoded on a data storage medium such as a CD-ROM or floppy disk and read utilising a corresponding data storage medium drive of a data storage device 830 . The application program is read and controlled in its execution by the processor 818 . Intermediate storage of program data maybe accomplished using RAM 820 . [0082] It is noted that this example embodiment is meant to illustrate the principles described in this invention. Various adaptations and modifications of the invention made within the spirit and scope of the invention are obvious to those skilled in the art. Therefore, it is intended that the appended claims cover all such variations and modifications as come within the true spirit and scope of the invention.
A method for use in indexing video footage, the video footage comprising an image signal and a corresponding audio signal relating to the image signals, the method comprising extracting audio features from the audio signal of the video footage and visual features from the image signal of the video footage; comparing the extracted audio and visual features with predetermined audio and visual keywords; identifying the audio and visual keywords associated with the video footage based on the comparison of the extracted video and visual features with the predetermine audio and visual keywords; and determining the presence of events in the video footage based on the audio and visual keywords associated with the video footage.
6
FIELD OF THE INVENTION This invention pertains to doors for motor vehicles and in particular, to truck doors and a method of manufacturing them. BACKGROUND OF THE INVENTION Utility truck bodies often have a box-like, non-aerodynamic appearance. This box-like appearance lends itself to relatively simple manufacturing processes for making doors for the truck bodies. However, a trend in the manufacture of trucks today is to provide the truck body with aesthetically pleasing lines, which calls for some curved body panels. The process of manufacturing curved body panels increases the cost and complexity of the truck door construction. Curved truck door panels are typically formed by a metal-forming process that requires the use of special dies. These dies are provided with a shaped surface for pressing the sheet metal into a desired shape, and greatly increase the cost of the truck body. Thus, there is a need for an inexpensive method for producing curved vehicle door panels. U.S. Pat. No. 5,239,753 to Kalis Jr. et al., which is incorporated herein by reference in its entirety, relates to a method that employs a jig having curved supports for imparting a curvature to an outer door panel. An inner door panel is fastened to the outer door panel by aligning openings in tabs of the outer door panel with openings in ribs of the inner door panel and by riveting the tabs to the ribs. This method of joining the inner and outer door panels increases the complexity and thus the expense of the door manufacturing process. SUMMARY OF THE INVENTION The present invention relates to sheet metal vehicle doors and a method of making them efficiently and inexpensively. In the present invention inner and outer door panels are fastened together in a manner that avoids the complexity of the prior art. The invention relates to a vehicle door including first and second sheet metal door panels. The first door panel includes fastening portions at a peripheral portion of the first door panel. Each of the fastening portions has at least a portion that extends at a first angle of less than 90 degrees with respect to a body of the first door panel. The second door panel includes flange portions at a peripheral portion of the second door panel. Each of the flange portions extends transverse to a body of the second door panel. The flange portions of the second door panel are disposed adjacent the fastening portions of the first door panel. A fastener connects at least two of the fastening portions to their associated flange portions. In a preferred embodiment, the first door panel is an outer door panel and the second door panel is an inner door panel. The first angle at which each of the fastening portions extends is about 45 degrees with respect to the body of the first door panel. The flange portions each extend from the second door panel at an angle of about 90 degrees with respect to the body of the second door panel. The fastening portions and their associated flange portions are preferably welded together. Because the fastening portions extend at an angle such as 45° with respect to the outer door panel body and are preferably welded to the flange portions, the method of the present invention is more efficient than that disclosed in the U.S. Pat. No. 5,239,753. The present invention does not require carefully aligning openings in tabs and ribs and riveting the tabs to the ribs. Moreover, by extending the fastening portions from the body portion of the outer door panel by a predetermined angle such as 45°, the inner and outer door panels may be welded together without any substantial warpage or distortion. A method of making a vehicle door according to the present invention generally includes the step of providing the first door panel with the peripheral fastening portions that each has at least a portion that extends from the body of the first door panel by the first angle of not greater than 90 degrees. The second door panel is provided with a plurality of the peripheral flange portions extending transverse to the body of the second door panel. The second door panel is connected to the first door panel by fastening the flange portions of the second door panel to the fastening portions of the first door panel preferably by welding. In a preferred method of the present invention the first door panel is an outer door panel and the second door panel is an inner door panel. The method includes the step of compressing the first door panel edgewise to provide the first door panel with a curvature. The fastening portions each extend preferably by about 45 degrees with respect to the body of the first door panel. At least two of the fastening portions are each fastened to their associated flange portion preferably by welding. Another preferred method of making a vehicle door according to the present invention includes the step of positioning the outer door panel in a jig having a curved surface portion. The outer door panel is compressed edgewise to provide the outer door panel with a curvature conforming to a curvature of the curved surface portion of the jig. The inner door panel is connected to a concave side of the outer door panel by engaging the inner door panel flanges with the outer door panel fastening portions. At least two of the fastening portions are each fastened to their associated flanges preferably by welding. The connected inner and outer door panels are removed from the jig. Other embodiments of the invention are contemplated to provide particular features and structural variants of the basic elements. The specific embodiments referred to as well as possible variations and the various features and advantages of the invention will become better understood from the detailed description that follows, together in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing the outside of a door assembly constructed in accordance with the present invention; FIG. 2 is a perspective view showing the inside of the door assembly of FIG. 1, in which inner and outer door panels are shown; FIG. 3 is an elevational view showing the inside of an outer blank from which the outer door panel shown in FIG. 1 is formed; FIG. 4 is an elevational view showing the inside of an inner blank from which the inner door panel shown in FIG. 2 is formed; FIG. 5 is an elevational view of the inside of the door assembly shown in FIG. 2; FIG. 6 is a top plan view of the door assembly shown in FIG. 5; FIG. 7 is an enlarged partial cross-sectional view as seen along the plane designated by lines 7--7 in FIG. 5; and FIG. 8 is an enlarged partial cross-sectional view as seen along the plane designated by lines 8--8 in FIG. 5. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Turning now to FIGS. 1 and 2 of the drawings, there is shown a door assembly 10 for a vehicle such as a truck. The door assembly 10 includes an outer door panel 12 and an inner door panel 14. The inner and outer door panels 14, 12 are preferably formed of sheet metal such as 20 gauge steel. The door assembly 10 is preferably used for a compartment formed in the side of a truck, which can hold tools, equipment and the like. The outer door panel 12 is formed from an outer sheet metal blank 16 shown in FIG. 3. The outer blank 16 includes a first door latch cutout 18, a generally rectangular central body portion 20 as defined by dotted margin lines 25 and four margins surrounding the body portion. The margins include a first side margin 22, a second side margin 24, a third end margin 26 and a fourth end margin 28. The fourth end margin 28 includes first hinge cutouts 30. The outer blank 16 also includes four fastening portions 32 that are each located within a region of one of the margins. Reference to a margin herein means a peripheral region of a sheet metal blank or panel located outside of the body portions 20, 36. The regions of the margins are each encompassed or bounded by solid lines 29 at the periphery of the blank and by the dotted margin lines 25, 27 as shown in FIGS. 3 and 4. For example, the margin 26 is defined as the area outside the body portion 20 that is bounded by margin line 25 and the entire outer edge designated by solid line 29 that intersects the line 25. The inner door panel 14 is formed from an inner blank 34 shown in FIG. 4. The inner blank 34 includes a second door latch cutout 35, a generally rectangular central body portion 36 defined by dotted margin line 27 and four margins surrounding the body portion 36. The margins include a first side margin 38, a second side margin 40, a third end margin 42 and a fourth end margin 44. The fourth end margin 44 includes second hinge cutouts 46. The first and second door latch cutouts 18, 35 have shapes such that when aligned they may receive a door latch 48 (shown in FIG. 2). The first and second hinge cutouts 30, 46 have shapes for receiving a hinge 50 when they are aligned. The inner and outer blanks 34, 16 are preformed into the shapes shown in FIGS. 3 and 4 by a process known to those skilled in the art such as by a sheet metal rolling and punching process. The inner and outer blanks 34, 16 are formed into the shape of the inner and outer door panels 14, 12 shown in FIGS. 1 and 2 by bending their margins and fastening portions in a manner known to those skilled in the art, such as by using a press break die. With respect to the outer blank 16 shown in FIG. 3, the fastening portions 32 are bent downward into the page preferably by about 45 degrees with respect to the body portion 20. The fastening portions 32 may be bent at any angle and in any configuration so long as when the door panels 12, 14 are connected together, the welding locations adjacent the flanges 38, 40, 42, 44 and their associated fastening portions 32 is far enough away from the outer door panel 12 to inhibit warpage and distortion of the panel 12 caused by heat produced during welding. The angle of each of the fastening portions 32 with respect to the outer blank body 20 is preferably selected such that when the door panels 12, 14 are connected, the peripheral edges of the fastening portions 32 are spaced by at least 1/8 inch from the outer door panel 12. This prevents substantially all warpage and distortion of the outer panel 12 as a result of welding. The outer blank margins 22, 24, 26 and 28 are then bent preferably by about 180 degrees out of the page with respect to the body portion 20 so that the margins 22, 24, 26 and 28 are substantially doubled over onto the body portion 20. This provides the outer blank 16 with reinforcement and blunt edges 52, thus adding an element of safety to the door assembly 10 by eliminating sharp edges. As shown in FIG. 4, the inner blank 34 is formed into the shape of the inner door panel 14 by bending the first and second side margins 38, 40 and the third and fourth end margins 42, 44 preferably by an angle of about 90 degrees into the page with respect to the body portion 36. As shown in FIGS. 2 and 4 this forms two flanges or ribs 54 extending transverse to the body portion 36 each having an arcuate end portion 56 and two flanges or ribs 58 extending transverse to the body portion 36. This forms the inner door panel 14 as best shown in FIGS. 2 and 5. The outer blank 16 is then preferably placed in a jig such as that described in U.S. Pat. No. 5,239,753. The outer blank 16 is preferably placed lengthwise in the jig so that the edges 52 at the bent first and second side margins 22, 24 are located between stop members and pusher members of the jig. The outer blank 16 is positioned adjacent a curved portion of the jig, so that the fastening portions 32 face away from the jig curved portion. The pusher members are advanced against one of the edges 52 at one of the bent first and second side margins 22, 24 to compress the outer blank 16 edgewise into the configuration of the curved surface of the jig. The side margins 22, 24 of the outer blank 16 are preferably crimped by an angle of about 25° with respect to the body portion 20 as shown in FIG. 2. This stiffens the outer door panel 12 and assists in maintaining its shape. This process forms the outer door panel 12, best shown in FIG. 1. The inner and outer door panels 14, 12 are aligned as shown in FIGS. 2 and 5. The flanges 54 and 58 of the inner door panel 14 are disposed adjacent and preferably in contact with their associated fastening portions 32 of the outer door panel 12. The arcuate end portions 56 of the inner door panel ribs 54 engage a concave surface of the body portion 20 of the outer door panel 12 that was created by the curved surface of the jig. The inner and outer door panels 14, 12 are preferably fastened together by welding near the locations of the intersection of the fastening portions 32 with their associated flanges 54 and 58. The welds are shown in FIGS. 7 and 8 and not in the other Figures to improve the clarity of the other Figures. The manner of welding between the fastening portions 32 and the flanges 54 and 58 is within the purview of those of ordinary skill in the art. For example, in FIGS. 7 and 8 spot welds 33 are made between the fastening portions 32 and their associated flanges 54 and 58. A hinge support may be welded to the interior of the door assembly 10 and a suitable sealant (not shown) may be applied to the hinge support. Joints 60 in the door assembly 10 are preferably sealed by caulking with a suitable material. Once the door assembly 10 is completely assembled, the latch 48 and the hinge 50 are mounted to it. The latch 48 preferably includes threaded studs for engaging threaded holes formed in the door assembly 10. The hinge 50 is preferably welded to the inner door panel 14. Although the invention has been described in its preferred form with a certain degree of particularity, it will be understood that the present disclosure of the preferred embodiments has been made only by way of example and that various changes may be resorted to without departing from the true spirit and scope of the invention as hereafter claimed.
A vehicle door is made by providing a first sheet metal door panel with fastening portions at a peripheral portion of the first door panel. The fastening portions each have at least a portion that extends at a first angle of not greater than 90 degrees with respect to a body of the first door panel. A second sheet metal door panel is provided with flange portions at a peripheral portion of the second door panel. The flange portions extend transverse to a body of the second door panel. The vehicle door is formed by fastening each of at least two of the fastening portions of the first door panel to an associated one of the flange portions of the second door panel.
1
FIELD OF THE INVENTION The invention relates to a method for tracking a mono- or stereo-laparoscope in connection with minimally invasive surgery. BACKGROUND OF THE INVENTION A method for performing operations is known from WO 87/06353, wherein a moving object present in a monitored room is detected by means of two cameras. The method merely determines the space coordinates of marked points. Minimally invasive surgery is gaining increased importance as an alternative to open surgery. It is already employed today in many hospitals in routine operations, for example the resection of the gall bladder. Up to now the camera guidance was performed by an assistant surgeon in cases where the surgery is performed laparoscopically in connection with an electronic image transmission to a monitor. However, such camera assistance is subject to a number of problems. The camera guidance can become unsteady because of the operator becoming tired and his or her concentration being reduced. Furthermore, instructions from the operating surgeon are misinterpreted time and again. In addition, independent actions by the assisting surgeon, which interfere with the course of the surgery, can quite often result in hard feelings between the operating surgeon and the assistant. The surgeon may feel psychologically hampered. Also, the job of camera assistant does not require the high-quality medical training of an assistant surgeon, so that it is basically too highly paid; and young doctors understandably do not like to do it. Holding devices which can be quickly removed and fixed in place have been used in guidance systems employed up to now. Examples of these are multi-link arms with ball and socket joints and joint locks, as well as the so-called "C bow" and a "scissors joint" of KFK-Karlsruhe. Furthermore, a robot with six degrees of freedom developed particularly for laparoscopic use is sold by the Computer-Motion company, which is equipped with a manual operating device as well as with a foot switch for controlling the operation. Although the known holding devices relieve the assistant surgeon of physical stress, they still have the disadvantage that they do not make a camera assistant unnecessary. This also applies, analogously, to the manually operated robot. Although the robot control can be operated by the surgeon himself by means of a foot switch, its operation distracts the surgeon from the actual surgical work. SUMMARY OF THE INVENTION Accordingly, the present invention has an object, among others, to overcome deficiencies in the prior art such as noted above. It is therefore the object of the invention to create a method for tracking a mono- or stereo-laparoscope in connection with minimally invasive surgery in which, on the one hand, an assistant surgeon is no longer necessary for tracking with a camera and, on the other hand, the operating surgeon is also relieved of additional control work, such as controlling a robot. In accordance with this and other objects apparent from the following description, the invention provides a method for tracking a mono- or stereo-laparoscope in connection with minimally invasive surgery. In accordance with a preferred embodiment of the invention, the surgical instruments are color-coded so that they can be identified by the image provided by one laparoscopy camera. In accordance with the invention, signals for controlling the robot are then derived from the position of the color-coded surgical instruments in the image generated by the laparoscopy camera. By means of evaluating this signal, the robot is then capable of automatically placing the laparoscope into such a position that the color-coded surgical instruments are continuously shown in the central area of the observing monitor. In addition, if a stereo-laparoscope having two cameras is used the distance between the laparascope head and the surgical instrument can also be controlled automatically. Thus, the method of the invention makes it possible for an appropriately controlled robot to align the cameras of a stereo-laparoscope automatically with the surgical instruments as soon as the operating surgeon issues a command to do this. The position of the camera in relation to the surgical instruments is thus determined according to the invention and in case of a possible misalignment the camera(s) automatically track(s) with the aid of the robot. The camera signals, which are provided anyway, are used for this and by means of them the surgical instruments or the markings on the surgical instruments are identified by means of the applied color. With the invention the signal source therefore is a marker or a marking in a suitable color, which is applied or provided in the vicinity of, or on the tip of, an instrument. The realization of this signal source is extremely simple and its cost negligible. In addition, every existing set of surgical instruments can also be provided with appropriate color marks later (i.e. retro-fitted), so that the object of the invention can also be employed extremely economically in respect to already existing, highly valuable surgical instruments. Furthermore it is also possible to embody the handle of an instrument, which as a rule was black up to now, in a suitable color. In this case the application of a marker could be omitted. On top of everything, such a signal source does not need space and it also does not affect the mechanical structure or the design of the instruments in any way. In the same way, an applied marking or applied marker does not interfere with the manipulation of the surgical instruments. This type of signal source, in the form of a colored marking, also does not require a special energy source, which is particularly advantageous because of the fact that, in any event, light supplied from the outside is urgently needed by the surgeon. Coding of the instruments can also be carried out by the provision of different colors, so that it is possible to apply the method in accordance with the invention selectively to different instruments. A color differentiation in video images can be quickly and cost-effectively realized by means of modern image processing devices. The method in accordance with the invention is furthermore designed in such a way that it can be realized with the aid of commercially available devices and components. The method of the invention operates in real time, and a high degree of safety in actual use is also dependably assured. Thus, by means of the method in accordance with the invention an operating surgeon is given a very comfortable and reliable method for guiding the laparoscope without having to lay the laparoscopy instrument aside. In accordance with a preferred embodiment of the invention the laparoscope always follows the color-coded surgical instruments in the so-called "continuous model". In this case the control is laid out in such a way that it acts only weakly in the central image area and strongly in its edge area. By means of this it is also assured that no interfering image movements occur during work in the operating area, for example when incising tissue. On the other hand it is also assured that the surgical instruments are not lost in the monitor image because of larger movements. The above and other objects and the nature and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments taken in conjunction with drawings, wherein: FIG. 1 is a schematic block diagram of a device for executing the method in accordance with the invention; FIG. 2 is a block circuit diagram of a classifier used in the device in FIG. 1; and DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the components used for executing the method in accordance with the invention will be described. Commercially available stereo-laparoscopes have a rigid tube with a diameter on the order of magnitude of 10 mm. On the end which is to be inserted into the site of the operation, a lens is provided if it is a mono-laparoscope, and two lenses are provided if it is a stereo-laparoscope. At the other end is a camera head into which one and two CCD cameras respectively have been integrated. The image provided by the camera(s) are available as video signals, for example in the RGB signal format. A robot with an appropriate robot control, for example from the Computer-Motion company, Goleta, Calif., USA, has six degrees of freedom, two of which are passive. By means of this the danger of injury to the patient by lateral forces, i.e. forces which extend transversely in respect to the laparoscope axis, is avoided. In this case a library is available for controlling such a robot, the preset commands move left(speed), move right(speed), move up(speed), move down(speed), zoom in(speed) and zoom out(speed) refer to the movements of an image on a monitor and generate the required control sequences for the robot joints. Furthermore, a commercially available video color digitizer, for example from the firm DataCube, Inc., Danvers, Mass., USA, is used for digitizing the recorded analog video signals. Such a digitizer has a multiplexer on the analog side, by means of which it is selectively possible to switch back and forth between two cameras, and on the digital side it has a module for color space conversion. In addition, a so-called pipeline processor for real time image processing, such as is offered by the DataCube company for example, is connected with a digitizer, such as the one from the DataCube company, by means of a 10 MHz data bus. A look-up table (LUT), stabilizing processors, a convolution module and additional modules are, for example, contained in such a processor. Such a processor has the required modules for image storage and processing; user- or use-specific initialization of this processor; and its wiring can be programmed. A central unit (CPU) is simultaneously used for administering the image processing hardware and as an interface for the robot control. As can be see from FIG. 1, the basic structure for executing the method in accordance with the invention is a control loop. A robot 1 holds a laparoscope, of which only the two CCD cameras 2 1 and 2 2 are represented in FIG. 1. The camera is optional for lateral control. Images recorded by means of the cameras 2 1 and 2 2 are transmitted in the RGB (red-green-blue) format to an image processing unit 3. The images present in the RGB format are applied to a multiplexer 30 of the image processing unit 3, which optionally switches back and forth between the two cameras 2 1 and 2 2 in a preset sequence of 25 Hz, for example, so that stereo images can be evaluated with only one image processing unit. However, it is intended that such image processing should differentiate pixels which come from a color marker or marking of a laparoscope (not represented in FIG. 1) and all the other pixels of the scene. Furthermore, the HSV (hue-saturation-value) color space is considerably better suited for a classification than the RGB color space, because in the HSV color space the color is represented by the two components "H" and "S", which are independent of intensity, and by the component "V", which is independent of color. For this reason an RGB-to-HSV color space conversion takes place in a converter 31 downstream of the multiplexer 30. Thus, the converter outputs a data stream including pixels from both camera images. Data words of the data stream correspond to the hue and saturation of the pixels. A classifier 32 is connected downstream of the converter 31, whose particular structure will be described below in reference to FIG. 2. In FIG. 2, the central component of the classifier 32 is a (16×16) bit look-up (LU) table 32. A 16-bit word is formed from respectively 8 bits of the color components "H" and "S" and is used as the address for the LU table 32-1. In this case the LU table 32-1 is pre-allocated in such a way that color values which are part of a marker receive the highest logical value of 255 (logical "1"), while all others receive the value zero (logical "0"). The LU table can be read at a rate of 20 MHz. Erroneous classifications can occur because of camera noise and saturation effects, causing marker pixels to be erroneously included with non-marker pixels, or vice versa. This danger is particularly great at a low signal level. For this reason the classification results obtained by means of the LU table are post-treated with the aim of correcting all pixels which were erroneously marked with the value 255 (those classified as marker pixels). It is acceptable in this case that pixels which are part of a color marker or marking are also given the value zero. All those pixels, which because of noise were assigned to a very low signal level or because of saturation to a very high signal level, are set to zero with the aid of the signal component "V". To this end the signal component "V" is passed through the bidirectional threshold value generator 32-2 and is multiplied with the output signal of the LU table 32-1 in a multiplication unit 32-3. The remaining residual errors are individual pixels or small groups of pixels in rapidly changing locations. In contrast, the marker image (the useful signal) is an extended area which moves very slowly. Based on this difference in the spatial and time behavior of the actual marker signal and the spurious signals, it is therefore possible to drastically reduce residual errors very efficiently by means of time and subsequent spatial low-pass filtering in a time low-pass filter 32-4 and a spatial low-pass filter 32-5 connected downstream of it. Following these, an appropriate threshold value operation is performed in a unidirectional threshold value generator 36-2, by means of which efficient non-linear filtering is realized. If filtering is performed by the addition of sequential frames and convolution with an evenly allocated mask, for example of the size (7×7), an error reduction by factors between 50 to 100 per classification error is achieved. A subsequent statistical evaluation in a statistics processor 33 1 downstream of the classifier provides the marker image center (SP). An additional statistics processor 33 2 , provided in parallel with processor 33 1 , finds the so-called circumscribing rectangle BB (bounding box) of the image of the marker or marking. Even if a considerable percentage of the pixels of the marker or marking are missing, it interferes only a little with the result compared with background pixels erroneously classified as marker pixels. The control loop 3 represented in FIG. 1 in the form of block diagrams finally terminates via the statistics processor 33 1 following the classifier 32. A controller 34 and a robot control 11 are connected downstream of the processor 33 1 . The center and the disparity are then determined from the image centers SP of the markers or markings in two successive images from the cameras 2 1 and 2 2 . A deviation of the center from its set position in the center area of the monitor image is used for a lateral control (move up-down-left-right), and the deviation of the disparity from every set value is used for a transverse control (zoom in-out). In all cases the restoring speed is proportional to an amount of deviation. In other words, the robot moves the laparoscope laterally (left/right, up/down) to keep the marker in the center of the images; and it moves optionally the laparoscope in and out (transverse or zooming direction) to keep the distance between the laparoscope-head and the surgical instrument. The two cameras are both aimed at a single convergence point at a certain distance from their lenses at the end of the laparoscope; if the marker is not at that distance, the center SP in the two stereo images will not correspond in position, but the images will be superimposed in position if the marker is at the convergence point. The stability of the controlled system is assured by the lateral and transverse feedback control. Furthermore, the system is quiet in the vicinity of the working point, which is very important for the surgeon; but the system is rapidly restored in case of large amounts of deviation. That is (for example in the lateral control), the system corrects weakly or not at all for small deviations between the marker center point SP and the screen center; but if the marker starts to move close to the edge of the screen, then the degree of correction is increased. The effect for the surgeon is that the instrument can be moved freely in a limited space without the viewing pictures jiggling, but the viewing picture automatically tracks the marker when the marker moves too far away from the center of the viewing picture. To increase the system dependability, the confidence in the measurements is continuously checked in a unit 36 performing confidence tests and a program control. For this purpose a contour data processor 35 is connected in parallel with the two statistics processors 33 1 and 33 2 connected downstream of the classifier 32. In the unit 36 performing the confidence tests and a program control, so-called regions of interest ROI (Region Of Interest), in which the image of a marker or marking is expected, are determined with the aid of the circumscribing rectangle BB delivered by the statistics processor 33 2 and the contour formed by the contour processor 35, and are applied by the unit 36 to the controller 34 as well as to the two statistics processors 33, as shown by the arrows in FIG. 1. Pixels located outside the ROI are not evaluated. It is furthermore necessary for a practical use of the method in accordance with the invention to determine what color the markers or markings are to have and how the classifier must be laid out in connection with a given marker or marking. For this purpose it is particularly necessary to determine how the LU table is to be laid out. To solve these problems, the invention has been developed to include a color selection program with the aid of a graphics interface and in accordance with the principle of "monitored learning by means of examples". All that is required for applying this method is a computer with the capability of displaying color images in real colors and a mouse interface for drawing polygons on the monitor. The core of the color selection method developed by the present inventor is a calculation of two-dimensional histograms in polygonal areas and a graphic representation of the results. In the graphic representation it is necessary to represent similar colors on points closely located near each other, so-called compact clusters, and unlike colors on points which are far apart, so-called disjunctive clusters. A number of color images of typical scenes are taken from video tapes made of actual operations, in which all possible colors occurring in the course of such operations are contained. Each one of these images is stored in the RGB format, i.e. each pixel of the images has an RGB value representing a color. Since it is sufficient to represent each color by two values, each RGB value is projected on a two-dimensional plane, i.e. the HS plane, containing the shade of color (hue) and the color saturation (saturation). In the course of this the number of pixels which are projected on the same HS position is added together in each position of the HS plane. A two-dimensional color histogram is obtained by means of this, in which the frequency of occurrence of all colors in the scenes is represented. A color histogram is represented to provide users with a graphic visual impression of the colors; in this case the color of each HS point has the average color intensity of all pixels registered in this point. A user is able to directly find existing color gaps (i.e. colors which do not appear during operations and so do not appear on the histogram), which can be used for color-coding the surgical instruments. The user can give the manufacturer objective color measurements (H, S) for this. For the sake of safety, the marked instrument or surgical instruments are again color-analyzed in the course of a classification layout in a hardware implementation in case of a possible color change of the selected color by the camera. In regard to the layout of the classifier 32, a user will therefore select the area whose colors later constitute a class by marking the so-called circumscribing polygons by means of the mouse. The calculation of the color histogram is limited to the interior of the polygons and the result is graphically represented. The user can then recognize the layout of the color clusters in this representation and he can fix the class limits, again by circumscribing polygons. In the process it is also possible to combine different colors in one class. The LU table 32-1 in the classifier 32 therefore receives the entry 255 only for the selected colors, as already explained above, while it receives the entry zero for all other colors. Extensive research by the inventor has shown that the selection of a color exclusively in accordance with a subjective impression is difficult and can often lead to unsatisfactory results. The reason for this is that the color temperature of the illumination, the color reproduction of the camera and the color reproduction of the monitor lead to color shifts. In addition, the same color seems to be differently perceived in different brightness. The above-described color selection method solves this problem since it is independent of color shifts of the cameras and the monitor and in this way makes the color selection and the outlay of the classifier more objective. Furthermore, the above-described color selection method can be used for any type of color classification, for example for quality control of colored textiles. In this case it is then possible to tailor it to a defined color in order to control the course of the threads of this color or the printing of a pattern, for example. It is furthermore advantageous that the user does not have to deal with numbers in any way. He can operate the color selection method in a very comfortable manner and achieve reliable results very quickly. It is furthermore possible to adapt the selectivity of the classifier to the respective problem in a very simple manner. In contrast to analytical classifiers or neural nets, there are no restrictions in regard to the form of the class limits. The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without undue experimentation and without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. The means and materials for carrying out various disclosed functions may take a variety of alternative forms without departing from the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.
For tracking a mono- or stereo-laparoscope in connection with minimally invasive surgery, where the laparoscope is moved by a robot in respect to surgical instruments located in the operation area, surgical instruments are color-coded and are identified in images provided by the camera of the laparoscope. Signals for controlling the robot are derived from the position of the color-coded surgical instruments in images generated by both cameras. The robot automatically brings the laparoscope into such a position that the color-coded surgical instruments are continuously shown in the center area of the monitor device and hold the laparoscope distance to the surgical instrument in the case of stereo. To prevent interfering movements of an image when working with the surgical instruments, the laparoscope continuously tracks the color-coded surgical instruments in such a way that the tracking of the image is controlled relatively lightly in the central area of the monitor, but strongly in its edge area.
0
BACKGROUND [0001] 1. Field of the Invention [0002] The present invention relates generally to an electronic locking system to secure consumable items in an image forming device, and particularly to an electronic locking system for a media tray to secure media sheets in an image forming device. [0003] 2. Description of the Related Art [0004] Image forming devices generally use consumable items like toner, media sheets, etc., to execute printing. The image forming device generally includes containers to hold the consumable items, e.g., the image forming device includes a media tray to hold media sheets. The consumable item may include valuable media sheets like doctors' prescriptions, bankers' bearer bonds, etc. As can be seen, it is necessary to securely maintain such valuable media sheets inside the image forming device, so as to prevent the media sheets from being improperly used. Even rather modestly valuable consumable material such as toner or ink, when used in an environment in which a relatively large number of people have access to the consumable material, may need to be secured so as to prevent their theft. [0005] A mechanical locking system is well known in the art for locking the media trays. In prior mechanical locking systems, a mechanical key is used to lock the media tray within the image forming device. However, it may be impractical for one user to carry the mechanical key for each and every media tray. Further, if any of the mechanical keys are lost, the manufacturer has to make a new serialized key. The time consumed in making the new serialized key may cause an unnecessary interruption in printing. Moreover, an unlocked media tray may be easily opened at an inopportune time, e.g., while the image forming device is printing, which generally causes paper jams. [0006] It would therefore be desirable to provide an effective locking system that obviates the above-mentioned problems. SUMMARY OF THE INVENTION [0007] Disclosed herein is an electronic locking system to secure consumable items in an image forming device. The system includes a first member to hold the consumable item and which is and movable between an open position and a closed position; a receiving member configured to receive the first member, the receiving member including a locking member; and a controller for controlling the locking member to lock the first member to the receiving member when the first member is in the closed position and to unlock the first member from the receiving member so that the first member is movable to the open position. [0008] In some embodiments, the locking member includes a drive device and a plunger such that the drive device moves the plunger between a lock and an unlock position. The controller is configured to control the drive device to move the plunger to engage a portion of the first member in the lock position, and to move the plunger to disengage from the portion of the first member in the unlock position. [0009] In some embodiments, the image forming device includes an I/O interface for receiving codes such that when a correct code is received the controller controls the drive device to move the plunger to the unlock position. [0010] In other embodiments, the controller controls the drive device to move the plunger to the unlock position only when the image forming device is not printing. [0011] In some embodiments, the controller records the time the correct code is entered into the image forming device and stores the recorded time along with the corresponding correct code in a memory. [0012] In another embodiment, the first member comprises a media tray, the consumable item comprises one or more sheets of media, and the receiving member comprises a tray receiving member. [0013] In other embodiments, the tray receiving member includes a sensing member that detects the media tray disposed within the tray receiving member and, in response to detection by the sensing member, the controller controls the drive device to move the plunger to the lock position. [0014] In other embodiments, following the controller controlling the drive device to move the plunger to the unlock position, the controller controls the drive device to move the plunger to the lock position upon completion of a predetermined time period during which the media tray remains positioned inside the tray receiving member as sensed by the sensing member. [0015] Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein, including the detailed description which follows, the claims, as well as the appended drawings. [0016] It is to be understood that both the foregoing general description and the following detailed description of the present embodiments of the invention and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention and together with the description serve to explain the principles and operation of the invention. BRIEF DESCRIPTION OF THE DRAWINGS [0017] The above-mentioned and other features and advantages of the various embodiments of the invention, and the manner of attaining them, will become more apparent will be better understood by reference to the accompanying drawings, wherein: [0018] FIG. 1 is a block diagram of one embodiment of an electronic locking system to secure consumable items in an image forming device according to the present invention; [0019] FIG. 2 is an isometric view of an image forming device that may be used in the system of FIG. 1 , including a media tray electronically lockable inside a tray receiving member; [0020] FIG. 3 is a partial cross section view of a bidirectional solenoid including a plunger attachable to the tray receiving member of FIG. 2 ; [0021] FIG. 4 is a front elevational view of the tray receiving member of FIG. 2 , illustrating a sensing member to be used with the media tray; [0022] FIG. 5 is a perspective view of the media tray of FIG. 2 , including a depression; [0023] FIG. 6A is a partial perspective view of the plunger of FIG. 3 partially moved downward to engage the depression provided on the media tray of FIG. 5 ; [0024] FIG. 6B is a partial perspective view of the plunger of FIG. 3 moved upward to disengage from the depression provided on the media tray of FIG. 5 ; [0025] FIG. 7 is a flow chart illustrating the use of the system of FIG. 1 ; [0026] FIG. 8 is a perspective view of the image forming device of FIG. 2 including a front cover having a door electronically lockable according to the present invention; [0027] FIG. 9 is a perspective view of a latching assembly affixed to a housing of the image forming device and engaged with a locking member included inside the image forming device of FIG. 8 ; and [0028] FIG. 10 is a schematic diagram of a latching member disposed on the door of FIG. 8 that moves downward to engage a pin member disposed on the latching assembly of FIG. 9 . DETAILED DESCRIPTION [0029] Reference will now be made in detail to the exemplary embodiment(s) of the invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. [0030] FIG. 1 illustrates one embodiment of an electronic locking system 100 to secure consumable items in an image forming device 110 according to the present invention. The electronic locking system 100 includes a first member 120 to hold consumable items, a receiving member 130 to receive the first member 120 , and a controller 140 . The first member 120 is movable between an open and a closed position relative to the receiving member 130 . In the closed position, the first member 120 is positioned inside the receiving member 130 . The receiving member 130 includes a locking member 150 . The controller 140 controls the locking member 150 to lock the first member 120 to the receiving member 130 in the closed position. The controller 140 also controls the locking member 150 to unlock the first member 120 from the receiving member 130 so that the first member 120 is movable to the open position. In the open position, the first member 120 provides access to the consumable item. Generally, the receiving member 130 is an opening formed inside a housing 200 (shown in FIG. 2 ) of the image forming device 110 and the first member 120 is movably positioned within the receiving member 130 . [0031] The locking member 150 comprises a drive device 150 a and a plunger 150 b . Essentially, the drive device 150 a moves/drives the plunger 150 b between a locked and an unlocked position. The drive device 150 a may be a motor, a bidirectional solenoid, a servo, etc. When the first member 120 is positioned inside the receiving member 130 , the controller 140 controls the drive device 150 a to move the plunger 150 b to the locked position. In the locked position, the plunger 150 b engages a portion of the first member 120 preventing the first member from moving relative to the receiving member 130 . Thus, when the first member 120 is locked to the receiving member 130 , the consumable items in the first member 120 are inaccessible to a user or anyone who may try to remove them. [0032] In accordance with an exemplary embodiment of the present invention, in order to unlock the first member 120 a correct code is required to be entered into the image forming device 110 . The correct code is a predetermined code stored in memory 170 in the image forming device 110 . The image forming device 110 includes an interface 160 to receive the code from the user. The code is either directly entered by a user or is entered through a device on which the code is stored. The device may be one of an ID card, a credit card, a thumbnail or a flash drive, and a biometric scanner (not shown). The biometric scanner may include at least one of a fingerprint scanner, a palm scanner, and an eye scanner. Once a code is received, controller 140 compares the received code with the code stored in memory 170 to determine whether the received code is a correct code. [0033] When the correct code is entered into the image forming device 110 , the controller 140 controls the drive device 150 a to move the plunger 150 b to the unlocked position. In the unlocked position, the plunger 150 b is retracted and disengages from the portion of the first member 120 allowing the first member 120 to move to the open position. In the open position the consumable item is accessible to the user. [0034] The controller 140 may record the time the correct code (or even an incorrect code in order to monitor unsuccessful attempts) is entered into the image forming device 110 , i.e., when the first member 120 is unlocked. The recorded time, along with the corresponding correct code, is stored in a memory 170 associated with the image forming device 110 . The recorded code and time helps in tracing the person who unlocked the first member 120 and when it was unlocked. [0035] In one embodiment, as illustrated in FIG. 2 , the first member 120 is illustrated as a media tray 120 and the receiving member 130 is a tray receiving member. The media tray 120 is configured to hold one or more media sheets and the tray receiving member 130 is an opening in the image forming device 110 . The tray receiving member 130 includes the locking member 150 . The locking member 150 includes a bidirectional solenoid 300 and the plunger 150 b coupled thereto (see FIG. 3 ). The bidirectional solenoid 300 moves the plunger 150 b between the locked and the unlocked position. The controller 140 energizes the bidirectional solenoid 300 in a first direction to move the plunger 150 b to the locked position. In the locked position, the plunger 150 b engages a portion of the media tray 120 . The controller 140 energizes the bidirectional solenoid 300 in a second direction opposite the first direction to move the plunger 150 b to the unlocked position. In the unlocked position, the plunger 150 b disengages from the portion of the media tray 120 . [0036] The media tray 120 is also movable between the open and the closed position. In the closed position, the media tray 120 is positioned inside the tray receiving member 130 in the image forming device 110 . The tray receiving member 130 includes a sensing member 400 (see FIG. 4 ), which detects if the media tray 120 is positioned inside the tray receiving member 130 . The media tray 120 includes tray size sensing fingers 510 (see FIG. 5 ) that compresses the sensing member 400 when the media tray 120 is positioned inside the tray receiving member 130 . When the sensing member 400 is compressed, the controller 140 detects that the media tray 120 is positioned inside the tray receiving member 130 and the controller 140 then energizes the bidirectional solenoid 300 to move the plunger 150 b to the locked position. [0037] In the locked position, the plunger 150 b engages a portion of the media tray 120 . For example, the plunger 150 b engages a depression 500 provided on the media tray 120 . As shown in FIG. 5 , depression 500 may be formed along an upper surface of a side member of media tray 120 . The depression 500 may be an opening, a hole, a cut-out or any other concave surface to engage and/or receive the plunger 150 b when plunger 150 b is in the locked position and prevent the media tray 120 from being removed from the image forming device 110 . The plunger 150 b may be movable vertically in upward and downward directions but other directions are also possible and come within the scope of the present invention. When the bidirectional solenoid 300 is energized in the first direction the plunger 150 b moves downwardly to engage (mate with) the depression 500 provided on the media tray 120 . When the plunger 150 b engages the depression 500 the media tray 120 is locked within image forming device 110 and cannot be removed. FIG. 6A illustrates the plunger 150 b partially moved downward to lock the media tray 120 . Essentially, when the media tray 120 is positioned inside the tray receiving member 130 the controller 140 energizes the bidirectional solenoid 300 in the first direction to move the plunger 150 b downward to lock the media tray 120 . [0038] Alternatively, solenoid 300 and plunger 150 b may be mounted on the bottom of the tray receiving member 130 such that plunger 150 b moves upwardly to lock the media tray 120 by engaging with depression 500 formed along a bottom surface along a side of media tray 120 (not shown). Similarly, the solenoid 300 may be horizontally mounted on one side of receiving member 130 so that plunger 150 b moves in a horizontal direction to engage with depression 500 defined along a side surface of the media tray 120 . [0039] As explained above, in order to unlock the media tray 120 , a code is required to be entered into the image forming device 110 . When the code is entered into the image forming device 110 , the controller 140 determines if the code is the correct code. It is possible that there may be more than one correct code to assist in identifying the user or for other reasons. If the code is a correct code, the controller 140 energizes the bidirectional solenoid 300 in the second direction to move the plunger 150 b to disengage from the depression 500 (as shown in FIG. 6B ) to unlock the media tray 120 . In one embodiment, the controller 140 controls the bidirectional solenoid 300 to unlock the media tray 120 only when the image forming device 110 is not printing. In another embodiment, the controller 140 controls the bidirectional solenoid 300 to automatically unlock the media tray 120 when the media tray 120 is empty. The date and the time when the media tray 120 is unlocked and the corresponding correct code are stored in the memory 170 of the image forming device 110 , as mentioned above. [0040] In one embodiment, after the controller 140 controls the bidirectional solenoid 300 to move the plunger 150 b to the unlocked position, the controller 140 controls the bidirectional solenoid 300 to return the plunger 150 b to the locked position after a predetermined time period (a timeout period) if the media tray 120 remains positioned inside the tray receiving member 130 as sensed by the sensing member 400 . This prevents the media tray 120 from being accidentally left unlocked for a prolonged period of time while remaining within tray receiving member 130 . Controller 140 may include a timer or the like for monitoring the timeout period. In this regard, the timer may be activated following controller 140 causing plunger 150 b to be moved to the unlock position and remain activated until media tray 120 is removed from tray receiving member 130 . The timer may also be activated when media tray 120 is returned to the closed position within tray receiving member 130 . [0041] FIG. 7 is a flowchart illustrating a method for electronically locking and unlocking the media tray 120 . The controller 140 determines if the media tray 120 is locked and secured at S 101 . If the media tray 120 is secured, the controller 140 determines if a code is entered into the image forming device 110 at S 102 . At S 103 , the controller 140 determines if the code is a correct, predetermined code. If the code is the correct, predetermined code, the controller 140 determines whether the image forming device 110 is performing a printing operation at S 104 . If the image forming device 110 is performing the printing operation, the controller 140 delays the unlocking of the media tray 120 , i.e., keeps the media tray 120 locked until the printing operation is complete. If the image forming device 110 is not printing, the controller 140 energize the bidirectional solenoid 300 in the second direction to unlock the media tray 120 at S 105 . [0042] In one embodiment, if the media tray 120 is secured at S 101 , the controller 140 determines if the media tray 120 is empty at S 106 . If the media tray 120 is empty, the controller 140 determines if the image forming device 110 is configured to automatically open at S 107 . If the image forming device 110 is configured to auto open, the controller 140 confirms if the print job in process at S 104 . In case the print job is not in process, the controller 140 energizes the bidirectional solenoid 300 to unlock the media tray 120 at S 105 . However, if the media tray 120 is not empty, the controller 140 keeps the media tray 120 locked. [0043] Once the media tray 120 is unlocked and becomes unsecured at S 108 , the controller 140 detects if the predetermined time period occurred without media tray 120 being opened. This can be seen in blocks S 110 and S 111 . If the timeout period occurred without media tray 120 being opened, the controller 140 energizes the bidirectional solenoid 300 to lock the media tray 120 at S 109 . In case the media tray 120 is removed before the timeout period has elapsed, the controller 140 determines if the media tray 120 is reinstalled at S 112 . If the media tray 120 is reinstalled, the controller 140 energizes the bidirectional solenoid 300 to lock the media tray 120 at S 109 . In one embodiment, when the image forming device 110 is powered on at S 113 , the controller 140 energizes the bidirectional solenoid 300 to lock the media tray 120 . [0044] In another embodiment according to the present invention, as illustrated in FIGS. 8-10 , the first member includes a cover 120 ′ for accessing at least one cartridge containing toner or ink, and the receiving member includes a cover receiving member 130 ′ disposed within the housing 200 of image forming device 110 . The cover 120 ′ may be pivotally attached to the housing 200 via hinges 830 . A portion of cover 120 ′ forms a door 800 movable between an open and a closed position. When the door 800 is in the open position, the toner cartridge(s) is/are accessible. The door 800 is coupled to a latching assembly 810 . The latching assembly 810 is affixed to the housing 200 . The latching assembly 810 includes a button member 820 and a spring 840 coupled thereto. The button member 820 is horizontally movable along a frame portion of latching assembly 810 between a latched and an unlatched position. An external force, such as a user applied force, may be applied on the button member 820 to move the button member 820 towards the left in FIG. 9 (shown by arrow A) to the unlatched position. When the external force is released, the spring 840 urges the button member 820 towards the right in FIG. 9 (shown by arrow B) to the latched position. [0045] The button member 820 is coupled to a latch member 850 movable therewith. The latch member 850 may include a pin member 860 . The latch member 850 is engageble with a latching member provided on the door 800 . For example, the door 800 may include a latching member 870 resembling an inverted “4” shape (shown in FIG. 10 ) that is engageble with the pin member 860 of the latch member 850 . FIG. 10 (A, B, and C) illustrates a downward movement of the latching member 870 (shown by arrow Y) to engage the pin member 860 when door 800 is moved to the closed position and latched to housing 200 . [0046] Usually, when the door 800 is not latched with the latching assembly 810 , a spring (not shown) coupled to the door 800 urges it to the open position. In the open position, the toner cartridge is accessible. In order to latch the door 800 to the latching assembly 810 , the door 800 is closed and the door 800 is moved downward by applying an external, user applied force thereto. When the door 800 is moved downward, the door's latching member 870 (the inverted 4 shape) moves into engagement with the pin member 860 (as shown in FIG. 10 , A-C). Specifically, as the door 800 is moved further downward, the door's latching member 870 temporarily moves the pin member 860 along with the button member 820 towards the left (indicated by arrow A in FIG. 9 ) to the unlatched position, overcoming the spring force applied by the spring 840 . This temporary displacement of pin member 860 can be seen in as latching member 870 moves from position A to position B in FIG. 10 . However, once the door's latching member 870 engages with the pin member 860 (position C of FIG. 10 ), the spring 840 applies a force to move the button member 820 along with the pin member 860 towards the right (indicated by arrow B in FIG. 9 ) to the latched position. In the latched position, the door 800 is latched with the latching assembly 810 . [0047] In the latched position, the controller 140 energizes the bidirectional solenoid 300 in the first direction to move the plunger 150 b in a direction indicated by arrow R (see FIG. 9 ) to the locked position. In the locked position, the plunger 150 b engages a portion of the latching member 810 . For example, the plunger 150 b may engage the button member 820 . Once the plunger 150 b is so engaged, the button member 820 may not be moved from the latched position, thereby locking the door 800 in the closed position. In the closed position, the door 800 cannot be opened. [0048] In general terms, the operation of the locking mechanism of embodiment of FIGS. 8-10 follows the flow chart of FIG. 7 . In order to move the plunger 150 b to the unlocked position, a code is entered into the image forming device 110 . The I/O interface 160 provides an option for entering the code for unlocking the door 800 of the cover 120 ′. When the code is entered into the image forming device 110 , the controller 140 determines if the code is the correct code for unlocking the door 800 . If the code is the correct code the controller 140 controls the bidirectional solenoid 300 to move the plunger 150 b in a direction indicated by arrow L to the unlocked position. The controller 140 energizes the bidirectional solenoid 300 in the second direction to move the plunger 150 b to the unlocked position. In the unlocked position, the plunger 150 b is disengaged from the button member 820 . [0049] When the plunger 150 b is disengaged from the button member 820 , the button member 820 may be moved to the unlatched position by applying an external force. In the unlatched position, the pin member 860 disengages from the door's latching member 870 and the spring coupled to the door 800 urges the door 800 to the open position. In the open position, the toner cartridge(s) is/are accessible. [0050] In one embodiment, the controller 140 energizes the bidirectional solenoid 300 to unlock the door 800 only when the image forming device 110 is not printing. In another embodiment, the controller 140 automatically energizes the bidirectional solenoid 300 in the second direction to unlock the door 800 when the toner cartridge is consumed. [0051] It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
An electronic locking system to secure consumable items in an image forming device and a method therefore. In one embodiment of the invention, an electronic locking system to secure media sheets includes a media tray to hold media sheets, a tray receiving member for receiving the media tray, and a controller. The tray receiving member includes a drive device and a plunger. The plunger is moved by the drive device between a locked and an unlocked position. The controller is configured to control the drive device to move the plunger to engage a portion of the media tray in the locked position and to move the plunger to disengage from the portion of the media tray in the unlocked position. The electronic locking system, incorporating the controller, provides an effective and efficient way to lock/unlock the media tray and eliminates the use of mechanical keys.
1
This application is a continuation of application Ser. No. 08/213,692, filed on Mar. 15, 1994 U.S. Pat. No. 5,450,933. BACKGROUND OF THE INVENTION The invention relates to a locking device for securing against external forces two objects adapted for movement relatively to each other, in two opposite directions of movement, the locking device generating in both directions of movement a restraining force counteracting the initiation of movement and--smaller compared with the restraining force--a movement resistance counteracting continued movement, whereby this locking device is furthermore constructed with, adapted for movement relative to each other, two locking device sub-assemblies of which one is coupled to one of the objects and another is coupled to the other of the objects, whereby furthermore due to the relative movement of these locking device sub-assemblies at least two variable-volume working chambers containing a working fluid can in the size of their respective working volume, be so influenced that the volumetric ratio of these working chambers .changes in opposing senses as a function of the direction of movement, whereby furthermore these working chambers -are connected to each other by a fluid exchange system which allows an exchange of fluid between the two working chambers in both exchange directions, in fact so that the resistance to fluid through flow during a fluid exchange process is greater at the start thereof than during its further progress. STATEMENT OF THE PRIOR ART Such a locking device is known from DE-C-1 459 182, in particular for securing doors and windows. In the case of the known locking device, a piston rod is passed in sealing-tight manner through end of a cylinder which is closed at both ends. Inside the cavity in the cylinder, the piston rod is connected to a separating piston which separates two working chambers from each other. The two working chambers are connected to each other by two flow paths which extend inside the piston. Associated with each direction of movement is a non-return valve which can only open in one direction of flow. Each non-return valve comprises a valve body which is pretensioned by a pretensioning spring in the shut-off position so that it is biased against an incoming flow aperture, closing this off in respect of the cylinder when the piston rod is stationary. When the piston rod is moved in a specific direction of movement in respect of the cylinder, then an above-atmospheric pressure builds up in one of the working chambers. This over-pressure acts on one of the non-return valves, opening it. When the piston rod starts to move, this pressure acts initially on just a small area of the valve body which is determined by the cross-section of the inlet aperture associated with this valve body. By reason of the smallness of this cross-section of the inlet aperture, a considerable above-atmospheric pressure is needed in the working chamber in order to lift the valve body off the sealing position in respect of the inlet aperture. Only then can there be flow between the two working chambers. Once the valve body has lifted off the inlet aperture, then it offers to the pressure in the diminishing working chamber a greater surface area on which to act so that it can be maintained in the open position at a relatively small level of over-pressure in the working chamber concerned. For details of this, reference is made to the comments made on lines 42 to 67 of column 6 of DE-C-1 459 182. The prior art solution makes it possible to lock a door in a relatively stable fashion in any desired position between its open and its closed positions. A relatively considerable pushing force is needed for a door or the like which is secured in any desired position to start to move. Therefore, any unintentional shock will not cause the door to change its position. On the other hand, once the door has been set in motion, a relatively minor amount of effort is sufficient to open or close it further. This per se advantageous behaviour of the door is certainly achieved at the expense of considerable structural cost which has hitherto prevented a wider application of the principle. The structural expenditure is caused particularly because two flow paths have to be made between the two working chambers. The provision of these two flow paths requires a multiplicity of bores, including axial bores, needed for forming the flow paths and which have to be disposed eccentrically in the piston. With regard to the state of the art, reference may also be made to U.S. Pat. No. 4,099,602 which is also concerned with door stays, particularly on motor vehicles. Also where these door stays are concerned, the locking action is generated solely by hydraulic means. In order to maintain a constant volume inside a cylinder, i.e. in order to maintain a constant sum of the working spaces in the two working chambers, a piston-piston rod unit is provided, in which the piston rod consists of two piston rod portions emanating from the piston and in opposite directions and which are passed in sealing-tight manner through two oppositely disposed end walls of the cylinder. Also this construction is based on the use of two flow paths through the piston, each associated with one direction of movement between cylinder and piston rod, so that the construction is correspondingly involved. Furthermore, this construction has the disadvantage that even after initiation of a movement of the piston rod in relation to the cylinder the external pushing force needed to open the relative non-return valve has to be maintained for the movement to continue over a relatively great distance. Therefore, the only choice open is so to dimension the non-return valves that a relatively low pushing force is sufficient to open them. This results in the disadvantage that even relatively minimal and unintentional pushing forces suffice to set the door in motion unintentionally. If one wishes to prevent this, then the non-return valves can be so adjusted that they can only be opened by a relatively considerable pushing force. However, this entails the disadvantage that a resistance to movement corresponding to this pushing force has to be overcome over the entire intended path of movement. OBJECT OF THE INVENTION The invention is based on the problem of indicating a locking device which, while retaining the advantageous operating behaviour of a looking device according to the principle outlined in DE-C-1 459 182, i.e. an operating behaviour in which after a relatively stronger pushing force, further continuance of a door movement generates a relatively low resistance to movement, allows a simplified structural complication so that it is therefore suitable for mass production. SUMMARY OF THE INVENTION In order to resolve this problem, it is according to the invention proposed for a locking device as defined in the background of the invention that the fluid exchange system comprises a series connection of two throttle means which are pretensioned into a closed position and through which flow is possible in both directions, each throttle means with a first through flow connection in conjunction with an associated working chamber and with a second through flow connection in conjunction with the second through flow connection of whichever is the other throttle means. A first pressure value at the first through flow connection of a throttle means is sufficient to open both throttle means and a second lesser pressure value at the first through flow connection of this throttle means is sufficient to maintain both throttle means open with continued through flow. By virtue of the fact that in the case of the embodiment of fluid exchange system according to the invention the two throttle means are connected in series with each other, the disposition of the bores inside a fluid conducting body accommodating the bores and forming the fluid exchange system can be substantially simplified. The locking device according to the invention can be used for the most widely diverse purposes, including the securing of doors and windows on buildings and movable objects such as motor vehicles. In that case, not only linear movements but for instance also rotary movements are involved. In the case of arresting linear movements, whereas it is possible to work particularly with linearly movable cylinder-piston units, in which the cylinder constitutes one sub-assembly of the locking device while the piston rod and piston represent the other, it is readily conceivable for the principle of the invention also to be applicable to rotary piston units in which the working chambers in a stator-cylinder are separated from each other by a rotor-piston. It is possible to take symmetrical and asymmetrical working conditions into account by a corresponding design of the throttle means. For example, it is conceivable for the first pressure value to be the same for both throttle means; this means that the same degree of pushing force (a pushing moment of equal magnitude) is needed in order even to initiate a movement in either direction. It means furthermore than then the stability of whichever setting is selected is of equal magnitude in relation to an unintentional pushing pulse in both directions. On the other hand, if it is desired to maintain the stability against unintended pushing greater in one direction because for instance the risk of pushing pulses arising are substantially greater for this direction of movement than for the other, then it is also possible for the first pressure value to be varied accordingly for the two throttle means. This, then, provides the advantage that the danger of unintended displacement due to a pushing pulse in one direction is reduced, in other words particularly in that direction in which unintentional pushing pulses are expected with greater probability and on the other hand it offers increased operating convenience in so far as it is possible more easily to initiate an intentional movement in the other direction of movement in which an unintentional pushing pulse is less likely. Also the second pressure value can be the same or different for both throttle points. Consequently, this can be used for instance in order to influence the user behaviour. For example, if it is desired to cause the user to keep a door only sufficiently open in the direction of opening as is absolutely necessary in order for instance to minimize the possible effect of wind, and if on the other hand one wishes to induce the user to close the door again as far as possible "willingly", then the second pressure value for the throttle determining the resistance to movement in the opening direction of the door can be made greater than the throttle determining the second pressure value for the resistance to movement when closing the door. By the asymmetry of the first and second pressure values, it is possible also to allow for situations where the relative movement of the object in a specific direction of movement is assisted also by other permanently acting forces, in other words for example the force of gravity, in fact so that the restraining force countering the movement in the direction of the force of gravity and/or the resistance to movement counteracting the movement in the direction of the force of gravity are greater than restraining force and/or resistance to movement for the movement directed in opposition to the force of gravity. In accordance with a preferred connection solution as a means of carrying out the principle underlying the invention, a throttle means comprises a through flow chamber with a first and second through flow connection and, adapted for movement along a movement path and adjacent this through flow chamber a throttle member which seals the through flow chamber, whereby the throttle member is pretensioned into a closed position by the action of pretensioning means, in which closed position the second through flow connection is isolated from the through flow chamber, whereby furthermore the first through flow connection is constantly connected to the through flow chamber whereby further in the closed position of the throttle member this latter offers a smaller working surface to a fluid pressure prevailing at the second through flow connection and a larger working surface in the same direction of exposure to a fluid pressure prevailing in the through flow chamber, whereby a pressure drop path being provided between the through flow chamber of the throttle means and the associated working chamber which is connected thereto via the first through flow connection. Such a connection arrangement gives rise to the following behaviour: when the pressure in one working chamber is increased, then a pressure builds up in a through flow chamber which is constantly connected to this working chamber via a first through flow connection. This pressure acts on a relatively large operating surface area of the throttle member adjacent this through flow chamber. Therefore, at a relatively low pressure in the through flow chamber associated with it, this throttle member yields and opens the second through flow connection of this through flow chamber. Consequently, the pressure out of this through flow chamber is also transmitted to the second through flow connection of the through flow chamber of the other throttle means. However, it is still unable to lift the throttle member of this other throttle means off the second through flow connection of the through flow chamber of the other throttle means. Only when a predetermined movement initiating force is exerted does the pressure in the working chamber provided for diminution become sufficiently great that the pressure in the second through flow connection of the through flow chamber associated with the other throttle means is sufficient to lift the throttle member of the other throttle means off the second through flow connection of the associated through flow chamber. Then pressure is also applied to the larger operating surface area of the throttle member of the other throttle means and this application of pressure lasts as long as, due to a further movement, there is a drop in pressure on the way from the through flow chamber of the other throttle means to the then enlarging working chamber. The pressure drop path can for instance consist of the cross-sectional setting of whichever is the first through flow connection. In this way, simple dimensioning of a bore makes it possible to adjust the pressure drop in the pressure drop path in keeping with whatever operating pattern is desired. It serves the object of a simple construction fluid exchange system within a fluid conducting member if the second through flow connections of the two throttle means are formed by the ends of a connecting passage which connects the two throttle means in series with each other. The two throttle means can be accommodated in a common fluid connecting member, again with the object of achieving the simplest possible fluid conducting member which is suitable for mass production. In this respect, the through flow chambers of the two throttle means can be coaxially disposed in the fluid conducting member and separated from each other by a separating wall which is traversed by a connecting passage which connects the through flow chambers of the two throttle means. The mouths of the connecting passage into the through flow chambers are then formed by the second through flow connections of the two throttle means. According to a preferred application of the invention, one locking device sub-assembly is constructed as a cylinder while the other is constructed as a piston rod unit with a separating piston between the two working chambers. In this case, then, the fluid conducting member in which the throttle means are accommodated can be a part of the piston rod unit and in particular it can be at least partly constituted by the separating piston in which relatively considerable space is available to accommodate the bores of the fluid exchange system, even if the overall device which is the locking unit has to be situated in the minimum of space by virtue of the application. For example, it is possible to accommodate in one separating piston member of a separating piston throttle member accommodating chambers for each of the two throttle means substantially concentrically with each other. These chambers can be separated from each other by a one-piece separating wall of the separating piston member. In this respect, the remote ends of these throttle member accommodating chambers can each be occluded by a plug. The plugs are fixed in the separating piston member. At least one of the plugs may be constituted by a piston rod portion. In this way, the separating piston can be constructed on the basis of a simple rotary part, sealing of the throttle member accommodating chamber taking place at the same time as the connection is established between the separating piston and the piston rod. In the case of this embodiment, the inlet chamber of a throttle means inside the throttle member accommodating chamber is defined by the throttle member and the separating wall. The plugs can be inserted into extensions of the throttle member accommodating chambers and fixed therein for example in that the extensions of the throttle member accommodating chambers have a larger diameter than the throttle member accommodating chambers themselves and in that the plugs each abut in an axial direction a transition shoulder between a throttle member accommodating chamber and its extension. In this respect, the plugs can be fixed in the extensions of the throttle member accommodating chambers by a deformation of the separating piston member, possibly by a flanging-over process. In this way, it is possible to obtain a sealing-tight closure of the throttle member accommodating chamber by the respective plug. Such a seal may be essential in order to avoid pressurized medium being applied to the back of the throttle member which would cause disturbances in the working cycle. The first through flow connections of the through flow chambers may be formed by radial bores in the separating piston member; these radial bores can then open out into annular spaces formed between a respective end portion of the separating piston member and an inner peripheral surface of the cylinder. In order to prepare these annular spaces and provide favourable fitting conditions for the separating piston within the cylinder, the separating piston member can be made so that midway along it in the axial direction of the cylinder there is a thickened portion which bears on an inner peripheral surface of the cylinder, possibly through an interposed gasket arrangement. With an eye to achieving minimal overall size, the pretensioning means acting on a throttle member housed in the respective throttle member accommodating chamber can be at least partially accommodated within the respective plug. This is particularly true in cases where the pretensioning means consist of elongate coil thrust springs which can be easily housed within a bore in the respective plug or respective piston rod. In this way, relatively long coil thrust springs can be used which have a virtually linear characteristic. Such a linear characteristic can be easily obtained in that in order to generate a specific pretensioning force, there is not used a correspondingly strong coil thrust spring, i.e. one which even after the shortest deformation path exhibits a correspondingly great and then further increasing restoring force. Instead, a long and weak spring is used which in the non-tensioned state has a substantially lower spring constant than corresponds to the desired pretensioning force, this coil thrust spring then, during installation, being subject to a pretension which is always present in the shut-off position and which corresponds to the desired pretension on the throttle member. In this case, the spring force of the coil thrust spring changes only slightly when the throttle member is lifted out of the position which produces a closure of the second through flow connection, so that upon continued movement, the resistance to movement can be kept even less. The working chambers can be bridged in one or more portions of the relative path of movement by a fluid by-pass. Thus one obtains this peculiarity: by virtue of such a fluid by-pass, the fluid exchange system containing the series-connection throttle means is short-circuited, i.e. a fluid exchange can take place between the two working chambers without the flow resistance in the fluid exchange system becoming effective. This means that the movement can be performed with even less force than that which corresponds to the per se already reduced resistance to movement. When a door is closed, it may be necessary to apply a specific minimum approach speed in order to engage certain closure means such as are used for instance in the case of motor car doors in order to cause the locking means to engage. In order to be able to attain this minimum approach speed to the closed position without regard to the resistance to movement which still exists during continued movement of the door stay or locking device, particularly if the door had been secured in such a position that it was only open a short distance and from which only a minimal path is available in order to achieve the minimum approach speed, then the use of a fluid by-pass may be a great help. By reason of such a fluid by-pass, the arresting effect of the locking device is not essentially restricted, because this fluid by-pass can be confined to a partial path in which there is no need for the locking effect in any case. Furthermore, the locking device can be combined with an electrical switch intended and suitable for instance for switching a room lighting source on and off where the room is to be closed by a door provided with the locking device. This has the advantage that the switch can be mounted in the same structural unit as the locking device. Mounting it on the locking device at the workshop where the latter is manufactured, using the assembly means available there, is extremely simple and entails a favourable cost. On the other hand, the need to install the switch on the structure to be equipped with the locking device is avoided, i.e. one working operation can be dispensed with in a production stage in which it is very much more difficult to have available suitable mechanical aids to install a light switch. The relative area of movement can be limited by flexible abutment means at least at one end. In the case of a car door, in particular, a resilient end stop is provided to define the opening, since as the door approaches the closed position, the locking means may be expected to provide a damping action. Basically, the fluid may be liquid or gas. If the working medium used is liquid, then care must be taken to ensure that the total space available within the working chambers can be varied by the longer or shorter immersion length of a piston rod and to see that this variation is taken into account. In principle, it is possible by having a small piston rod cross-section to minimize the variations in volume as a function of the piston rod immersion length in the cylinder, making them in some cases even so small that a very slight under-filling of the working chambers is sufficient for compensation although in such a case a certain backlash must be anticipated in whichever position is selected. However, it is also possible to continue the piston rod unit beyond the two ends of the separating piston in which case the piston rod can then be passed in sealing-tight manner through respective bushings at both ends of the separating piston. In this way, the space available in the working chambers is constant regardless of the piston rod position. In that case, however, certain compensating means are needed in order to allow for fluctuations in temperature and any leakage losses. Such compensating means might be provided by bounding one of the working chambers by a closure wall braced by a hard springing means. A double piston rod with two passages through corresponding working chamber end walls is not absolutely vital. If one wishes to dispense with extending the piston rod through a second working chamber end wall, then the compensation of volume can also be achieved by providing adjacent at least one of the working chambers a flexible compensating space which may be separated from the liquid space by a partition. In such a case, a valve wall can be provided between the partition and the separating piston which sub-divides the respective working chamber into two partial working chambers and contains two oppositely poled non-return valves. Of these oppositely poled non-return valves, that which leads from the partial working chamber which is closer to the separating piston to the partial working chamber which is more remote from the separating piston is pretensioned by a relatively strong pretension in the direction of closure. This pretension then ensures that in the inoperative position of the device, considerable pushing force is needed in order to initiate the movement. Once the movement has been started, then only the piston rod has any volume-compacting effect. By reason of the hard sprung non-return valve, then, only a very small volumetric flow takes place. This small volumetric flow therefore suffers a relatively low resistance to through flow in the hard sprung non-return valve. In this way, once the movement has been initiated, the resistance to movement can always be kept sufficiently low. From another point of view, the invention refers to a system for fluid exchange between two working chambers, particularly of a locking device which is constructed as a cylinder-piston unit, locking device in question being in particular of the type described hereinabove. This fluid exchange system comprises a through flow chamber accommodated within a fluid conducting member, said through flow member being defined by a sealing piston disposed for movement within it, whereby furthermore this through flow chamber can be connected via a first connection to one working chamber, whereby furthermore a constantly open second connection of the through flow chamber leads to the other working chamber, whereby furthermore on the same side as the first connection, an end face of the sealing piston is pretensioned by a sealing piston pretensioning means into a closed position against the first connection, whereby furthermore the end face on the first connection side, when in the closed position, offers a smaller cross-section to the fluid acting on it through the first connection, and whereby the end face on the first connection side offers a larger fluid actuating cross-section to a fluid pressure prevailing in the through flow chamber. Such a fluid exchange system is in turn known from the already above-mentioned U.S. Pat. No. 4,099,602 in fact from FIG. 2 thereof. In the case of this known construction, there are two sealing pistons disposed inside the through flow chamber of the fluid conducting member. A closed spring chamber is constructed between these sealing pistons. This spring chamber accommodates a coil thrust spring which spreads the two sealing pistons apart from each other. Each of the two sealing pistons carries a ball on the side remote from the spring chamber. This ball co-operates with respective first connections and forms the smaller fluid-actuated cross-section of a respective end face on the same side as the first connection. Therefore, each ball co-operates with a first connection. The two sealing pistons have a diameter which exceeds the ball diameter so that a larger fluid exposed cross-section is available also at the respective sealing piston. The two first connections of each through flow chamber are respectively connected to a working chamber. Furthermore, the second connection of each through flow chamber is connected by a pipe to whichever is the other working chamber. When the pressure in one of the two working chambers rises, this increased pressure is on the one hand applied via the first connection to the associated small fluid-exposed cross-section of the sealing piston associated with this one through flow chamber and furthermore it is applied via the second connection to the other through flow chamber at the larger fluid-exposed cross-section of the other sealing piston associated with this other through flow chamber. Therefore, this over-pressure in one working chamber can open two mutually parallel flow paths in the direction of the other working chamber. The resulting resistance to through flow through these two parallel connected flow paths depends upon the spring force and furthermore upon the smaller fluid-exposed cross-section of one sealing piston and the larger fluid-exposed cross-section of the other sealing piston. With increasing pressure in one working chamber, firstly the sealing piston of the other through flow chamber will be lifted off its first connection. Identical circumstances arise when the pressure rises in the other working chamber. A locking device in the form of a cylinder-piston unit is known from DE-C-1 459 182. In this case, the fluid conducting member in the form of a separating piston unit is mounted on the piston rod of the cylinder unit, between two working chambers of the cylinder-piston unit. Upon displacement of the piston rod in respect of the cylinder of the cylinder piston unit, according to the direction of displacement, a pressure rise occurs in one or other of the working chambers. Now, once again, two through flow chambers are formed in the fluid conducting members and each of these two through flow chambers accommodates one throttle piston. Each of the working chambers is connected to an associated through flow chamber via a first connection. The relevant first connection can be occluded by the throttle piston so that the pressure in the respective working chamber acts via the first connection on the smaller fluid-exposed cross-section of whichever is the relevant throttle piston. Each throttle piston is pretensioned by a coil thrust spring in the direction of the first connection of the associated through flow chamber. The throttle piston does not seal the through flow chamber but allows a very restricted connection between the respective through flow chamber and a back of the respective throttle piston. If in one of the working chambers an over-pressure occurs due to its becoming smaller, then via the associated first connection, this increased pressure is transmitted via the associated first connection to the smaller fluid-exposed cross-section of the associated throttle piston so that this throttle piston lifts off the first connection. From that point on, the fluid of this working chamber acts on a substantially enlarged fluid-actuated cross-section of the throttle piston in fact because a pressure drop takes place between the respective through flow chamber and the other working chamber. This means that once the first connection has opened, the piston rod can be displaced smoothly in respect of the cylinder. Furthermore, this means that in the case of a use of the piston-cylinder unit as a locking device for a door, once the door has been pushed, it will move relatively easily against the action of the locking device. The symmetry of the separating piston unit ensures substantially symmetrical conditions so that the arresting or locking behaviour is substantially the same regardless of the direction in which the door is moved. The invention is based on the problem of, on the premise of the structural principle according to U.S. Pat. No. 4,099,602, obtaining a fluid exchange system which provides a similar flow characteristic to the fluid exchange system according to DE-C-1 459 182. In order to resolve this problem, it is according to the invention proposed to associate with the second connection a pressure drop path and that a flow path extending from the first connection towards a second connection is by-pass free when there is a flow in this direction so that for a predetermined minimum pressure acting on the smaller fluid-exposed cross-section the end face on the same side as the first connection lifts off the first connection and subsequently the large fluid-exposed cross-section inside the through flow chamber is exposed to a pressure which is dependent upon the flow rate through the through flow chamber and keeps the first connection open until there is a short fall on a predetermined minimum through flow rate. In accordance with a preferred embodiment, the fluid conducting member is accommodated within and substantially concentrically with a cylindrical cavity, the first connection, extending in the direction of the axis of the cylindrical cavity, communicating with a first connection chamber inside the cylindrical cavity, this first connection chamber being in turn connected to one working chamber or forming such a working chamber and whereby furthermore the second connection is disposed substantially radially in respect of the axis of the cylindrical cavity and being connected to a connecting line which--extending preferably annularly cylindrically between the fluid conducting member and an inner peripheral surface of the cylindrical cavity--leads to the other working chamber. In this respect, the pressure drop path may be constituted by the second connection itself which is constructed as a bore. This last-mentioned construction has over the construction according to DE-C-1 459 182 the great advantage that the pressure drop at the bore can be very accurately established by corresponding calibration of this bore so that also the behaviour of the fluid exchange system can be adjusted with corresponding accuracy and at a reasonable production cost. The first connection and the second connection can be separated from each other by an annular gasket which is formed between an outer peripheral surface of the fluid conducting member and an inner peripheral surface of the cylindrical cavity. In order to achieve a compact structural design, it is recommended to dispose the fluid conducting member inside a separating piston unit which is disposed within a cylindrical tube. The sealing piston pretensioning means can be formed at least partly by a coil thrust spring. The sealing piston pretensioning means can be accommodated in a closed chamber constructed inside the fluid conducting member. The pretension can however also be set up in that the sealing piston pretensioning means is at least partly derived from a fluid pressure in the other working chamber. In contrast to the fluid exchange system according to DE-C-1 459 182, the fluid exchange system according to the invention is suitable for through flow in opposite directions whereby in a first through flow direction the first connection acts as an input while the second connection serves as an output while in a second direction of through flow the second connection serves as an input and the first connection serves as an input of the fluid exchange system. If it is desired to achieve different flow conditions according to the direction of flow between the two working chambers, then it is possible for the flow from the first to the second working chambers to use a fluid exchange system described hereinabove and for a fluid flow in the opposite direction, i.e. from the other working chamber into the one working chamber, to use a simple differential pressure dependently opening non-return valve. The non-return valve can thereby be constructed as a slide valve, in which case the fluid conducting member may be constructed as a valve slide member within a cylindrical cavity being pretensioned into a closed position and being capable of being moved into an open position by a pressure derived from the pressure in the other working chamber. In particular, the fluid exchange system according to the invention can be accommodated within a separating piston unit of a cylinder-piston unit and may within the cylinder isolate two working chambers from each other. Care must be taken that already in the case of a single fluid exchange system of the aforementioned type a differing flow behaviour is achieved according to the direction of movement between piston rod and cylinder tube because in one direction of movement initially only the smaller fluid-exposed cross-section and only after opening of the first connection also the larger fluid-exposed cross-section will be acted upon whereas in the other direction of movement the larger fluid-actuated cross-section will be acted upon at the same time. According to a further embodiment of a cylinder-piston unit, it is envisaged that there are within the separating piston unit two fluid exchange systems between the working chambers of the cylinder-piston unit, being connected in series, in fact so that the first connections of the two fluid exchange systems are connected to each other while the second connections of the two fluid exchange systems are each connected to a working chamber of the cylinder-piston unit. With this configuration, for a corresponding dimensioning, the through flow behaviour is respected, according to the direction. The embodiment with two series-connected fluid exchange systems is preferably used in the case of cylinder-piston units in which the separating piston unit is accommodated inside a tubular cavity which is closed at both ends by a guiding and sealing unit, a piston rod connected to the separating piston unit being passed in sealing-tight manner through one of the guide and sealing units, a piston rod extension piece connected to the separating piston unit being passed through the other of the guide and sealing units. In the case of such an embodiment, it is possible to establish entirely symmetrical operating conditions in both directions of movement. In the case of another embodiment of cylinder-piston unit, the separating piston unit is disposed inside a tubular cavity sealed at one end over its entire cross-section while a guiding and sealing unit is only provided at the other end, a piston rod connected to the separating piston unit being passed through the guiding and sealing unit, measures being taken to compensate for the variation in the displacement volume of the piston rod inside the cylindrical cavity upon a displacement of the piston rod in respect of the tubular cavity, generating a push-out force which acts on the piston rod. With this embodiment, too, a single fluid exchange system or a series arrangement of fluid exchange systems may be used. As a way of compensating for the variation in the displacement volume of the piston rod inside the cylindrical cavity when there is a displacement of the piston rod in respect of the cylindrical cavity, it is possible for the fluid filling to be constituted entirely by a compressible gas. Furthermore, it is possible for the cylindrical cavity to be partly filled with pressurized gas whereby in this case a floating piston or a separating diaphragm may be provided between the pressurized gas and the fluid. Finally, it is also conceivable to dispose at a fluid-filled part of the cylindrical cavity a floating piston which acts against the fluid by spring pressure. In the case of a cylinder-piston unit with a piston rod lead-through at only one end, in a state of equilibrium there is a greater pressure in that working chamber of the cylinder cavity which is at the same end as the piston rod and a lower pressure in the working chamber which is remote from the piston rod, regardless of whether the cylinder cavity is filled with pressurized gas or with a liquid which is in turn subject to gas pressure or spring pressure. If it is desired to use approximately the same forces to push the piston rod in or out, as is frequently desirable for instance if the cylinder-piston unit is to be used as a locking device for securing motor car doors, then it must be borne in mind that during closure of the door, a push-out force acts on the piston rod which emanates from the gas pressure or the fluid pressure. This means that pushing it in, corresponding substantially to closing the door, means that a greater force must be exerted than that which is needed to push out or in fact open the door. Nevertheless, in order to achieve at least approximately compensated movement conditions during opening and closing, when there is only a single fluid exchange system inside the separating piston unit its first connection can be connected to a working chamber of the cylinder cavity which is on the piston rod side--this working chamber on the piston rod side will be referred to hereinafter as the rod chamber--while on the other hand a second connection of this fluid exchange system can be connected to a working chamber of the cylinder-piston unit which is remote from the piston rod and which is hereinafter referred to as the end chamber. If the end chamber and the rod chamber are both filled with a fluid and one of these chambers, for example the end chamber, has next to it a flexible gas filling bounded by a floating piston, then the movement behaviour of the piston rod is influenced accordingly, in fact in that the piston rod is able to move away resiliently in the direction of the floating piston. If this is to be avoided--subject to the end chamber abutting the floating piston--the end chamber can be sub-divided into a partial end chamber on the piston rod side and a partial end chamber which is remote from the piston rod, a further fluid exchange system of the aforedescribed type being installed in a stationary partition, in fact in such a way that its first connection communicates with the partial end chamber which is close to the piston rod. If a cylinder piston unit is provided as an aid to lifting a structural part, for example a boot lid of a motor vehicle, then it is preferable to use an embodiment which has only one cylindrical tube end fitted with a lead-through for the piston rod, a hollow piston member being provided as part of the separating piston unit, which bears in sealing-tight manner against an inner peripheral wall of the cylinder cavity. Furthermore, the fluid conducting member of the fluid exchange system is also accommodated in this hollow piston member, in fact in such a way that the first connection of the through flow chamber communicates with a working chamber, referred to as a rod chamber, on the same side as the piston rod and in such a way that the fluid conducting member co-operates with the hollow piston member as a valve slide, forming a non-return valve which leads to the rod chamber from a working chamber of the cylinder cavity which is remote from the piston rod and which is referred to as the end chamber. In accordance with a further aspect, the invention relates to a structural sub-assembly comprising a basic structure and a movable structural element which is adapted for movement against the force of gravity between an extreme low position and an extreme upper position in relation to the basic structure, being guided by guide means, whereby to facilitate movement of the movable structural element between the extreme low position and the extreme high position and in order to arrest the movable structural element in intermediate positions, at least one cylinder-piston unit filled with a pressurized fluid is provided, whereby furthermore this cylinder-piston unit is constructed with a cylindrical tube, a tubular cavity constructed inside this cylindrical tube, a guiding and sealing unit at one end of the tubular cavity, a sealing-tight closure at the other end of the tubular cavity, a piston rod inserted through the guiding and sealing unit, a separating piston unit connected to the piston rod inside the tubular cavity, a rod chamber on the piston rod side of the separating piston unit, an end chamber on the side of the separating piston unit which is remote from the piston rod and a filling of pressurized fluid in the rod chamber and in the end chamber. Measures are taken to compensate for variations in the displacement volume of the piston rod inside the tubular cavity upon displacements of the piston rod in relation to the tubular cavity, which measures generate a push-out force on the piston rod. A fluid exchange system is provided between the rod chamber and the end chamber. Of the two parts: cylindrical tube and piston rod, one is connected to the basic structure while the other is connected to the movable structural element. The weight of the movable structural element, the guide means of the movable structural element, the points of attack between the piston cylinder unit, the basic structure and the movable structural element, the cross-section of the tubular cavity, the cross-section of the piston rod, the fluid filling in the tubular cavity and the fluid exchange system are so constructed and dimensioned that the following conditions are satisfied: a) when the movable structural element is in a midway position, at rest, the end chamber and the rod chamber are separated from each other and the movable structural element is secured against sinking by an end chamber fluid contained in the end chamber and against rising by a rod chamber fluid contained in the rod chamber, in that aa) the pressure of the end chamber fluid bearing on a full cross-section of the separating piston unit exerts a push-out effect on the separating piston unit, ab) by this push-out effect in the rod chamber, a pressure of the rod chamber fluid is generated which acting on the differential cross-section between the full cross-section of the separating piston unit and a rod cross-section of the piston rod exerts a push-in effect on the separating unit, ac) the push-in effect generated by the rod chamber pressure, together with an additional push-in effect emanating from the weight of the movable structural element maintains equilibrium with the push-out effect, the pressure in the rod chamber being greater than the pressure in the end chamber, ad) a lifting-purpose non-return valve system opening from the rod chamber to the end chamber is exposed to the pressure in the rod chamber with a smaller fluid exposed cross-section and is so adjusted that in a state of equilibrium it cannot be opened by the pressure in the rod chamber, ae) a lowering-purpose non-return valve system opening from the end chamber to the rod chamber is exposed to the pressure in the end chamber and is so adjusted that in a state of equilibrium it cannot be opened by the pressure in the end chamber, b) a brief slight application of an external lifting force on the movable structural element results in an increase in the pressure in the rod chamber which acts on the small fluid exposed cross-section of the lifting-purpose non-return valve system which leads to an opening of the lifting-purpose non-return valve system; ba) once the lifting-purpose non-return valve system is opened, there is a flow of fluid from the rod chamber to the end chamber; bb) the flow from the rod chamber to the end chamber suffers a drop in pressure in a pressure drop path situated between the lifting-purpose non-return valve system and the end chamber, bc) as a result of this pressure drop, there is established inside the lifting-purpose non-return valve system an intermediate pressure which is greater than the pressure in the end chamber; this intermediate pressure acts on a larger fluid exposed cross-section of the lifting-purpose non-return valve system in the opening sense of the lifting-purpose non-return valve system; as a result of the fluid flow from the rod chamber through the lifting-purpose non-return valve system to the end chamber, the pressure in the rod chamber drops; the balance is modified and the piston rod is pushed out of the cylindrical tube; bd) the pushing of the piston rod out of the cylindrical tube brings about a continued flow from the rod chamber to the end chamber; this continued flow continues to ensure maintenance of an intermediate pressure in the lifting-purpose non-return valve system; this inter-mediate pressure furthermore acts on the larger fluid exposed cross-section of the lifting-purpose non-return valve system and holds it open, even when the exertion of external lifting force ceases; the pushing-out movement of the piston rod and thus the raising of the movable structural element are therefore continued by the action of the cylinder piston unit, without the need for the continued application of an external lifting force; be) if during the continued push-out movement of the piston rod a depressing force is briefly applied to the movable structural element, then the rate of flow through the lifting-purpose non-return valve system drops; the intermediate pressure acting on the larger fluid exposed cross-section of the lifting-purpose non-return valve system drops;.the lifting-purpose non-return valve system is closed again; the movable structural element comes to a standstill and remains stationary even if the depressing force ceases again; c) when the movable structural element is in an intermediate position and at rest, it can be moved by a minor lowering force in the direction of the extreme low position in that ca) firstly there is an increase in the pressure in the end chamber, a slight increase in the pressure in the end chamber leading to an opening of the lowering-purpose non-return valve system, cb) consequently there is an approximation of pressures between the end chamber and the rod chamber, cc) and the pressure acting on the piston rod cross-section and prevailing in the rod chamber and end chamber once this approximation of pressure is established between the two chambers produces a force to push the piston rod out and this force only slightly exceeds the gravity-induced piston rod push-in effect of the movable structural element on the piston rod, so that it can be overcome by said minor lowering force to be permanently applied until a desired lower position of the movable structural member, optionally its extreme low position, has been reached. The structural sub-assembly can, particularly as a basic structure of a motor vehicle body and as a movable structural element, comprise a hinged member, for example a boot lid or a tail gate of an estate car or an engine bonnet. The result then is that the hinged member can easily be raised by hand. Over a major part of its pivoting path it is automatically lifted by the cylinder-piston unit. It can be arrested in midway positions in that a brief depressing force is exerted on the hinged member and it then stays in the selected position even if this depressing force is removed again. If it is intended then to open the hinged member further, then a minimal and brief application of outside lifting force on the hinge member is sufficient to trigger its continued automatic opening until the hinged member comes to a standstill by reason of an abutment e.g. inside the cylinder piston unit or until once again a depressing force is provided by hand. If it is intended to close the hinged member, then it is sufficient to exert a relatively minor but steady lowering force on the hinged member until a desired lower position is reached. If, once this lower position of the hinged member is reached, the steady lowering force is removed, then the hinged member remains in the new midway position attained. If the hinged member is to be completely closed, then the steady lowering force is exerted until such time as the hinged member is either closed or until the push-out force on the rod is no longer sufficient to maintain balance against the force of the weight of the hinged member so that this drops down. Preferably, adjacent the position of complete closure of the hinged member, it is preferable to provide a small range of movement in which the push-in force exerted by the weight of the hinged member exceeds the push-out effect of the cylinder piston unit so that the hinged member is able easily to snap into place in the lock or, as desired, can automatically drop into the lock., The outside lifting force needed to trigger the outwards movement from a midway position of the hinged member, the depressing force needed to arrest the hinged member in a midway position and the steady lowering force needed to close the hinged member are preferably so adjusted that they can easily be applied by even a weak person. Preferably, these forces should be less than 100N and preferably less than 50N. The cylinder piston unit can thereby be substantially completely filled with gas plus a small quantity of liquid lubricant. Furthermore, the piston cylinder unit can be partly filled with liquid if either the rod chamber or the end chamber has adjacent to it a volume of compressed gas, possibly separated from the fluid by a floating piston or a movable diaphragm. Furthermore, it is possible to have adjacent the end chamber or the rod chamber a separating piston which maintains a pretension in the liquid by means of a mechanical springing means. The structural unit can be constructed with one or a plurality of cylinder-piston units. In the motor vehicles field, frequently two cylinder-piston units are used in conjunction with hinged members, one being provided at each of the two edges of the hinged member. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS The invention is explained in greater detail hereinafter with reference to embodiments shown in the accompanying drawings, in which: FIG. 1 shows a hydraulic blocking device with a double piston rod which at both ends of the separating piston is guided through respective end walls of the associated working chamber; FIG. 2 shows a modified embodiment in which in order to compensate for the volume of the varying piston rod space a resiliently braced end wall is provided, a coil thrust spring being used to provide a resilient bracing arrangement; FIG. 3 shows a further modified embodiment which corresponds substantially to that shown in FIG. 2 but with the coil thrust spring replaced by a space containing compressed gas; FIG. 4 shows a further embodiment of a hydraulic locking device in which the separating piston is simplified and a bottom valve unit is provided; FIG. 5 shows a further embodiment intended particularly for use on vertically adjustable hinged members of motor vehicle; FIG. 6 shows a motor vehicle with a tail gate in the closed position, a locking device according to FIG. 5 being used, the hinged member being shown in solid lines to illustrate the closed position and in broken lines to show the open position, and FIG. 7 shows a motor vehicle according to FIG. 6 with the hinged member in a midway position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With regard to the embodiment shown in FIG. 1, the locking device is clamped between two fixing points 1, 2 the distance between which can be varied. The locking device consists of a cylinder 3 and a piston rod 4 which is adapted for movement relatively to it. In the cylinder 3, two working chambers 5, 6 are separated from each other by a separating piston 7. The separating piston 7 comprises connecting passages 8, 9, 10 which allow fluid to flow from the working chamber 5 into the working chamber 6. In the rest position, the working chambers are occluded by two throttle members 11, 12 by the force of two pretensioning springs 13, 14. The throttle member accommodating chambers 15, 16 are filled with air or gas at ambient pressure and are sealed in respect of the fluid filled working chambers 5, 6 by sealing elements 17, 18, 19, 20. In the throttle member accommodating chambers 15, 16, the throttle members 11, 12 define through flow chambers 30, 31. The connecting passages 9, 10 each form a first through flow connection 9, 10 to the two through flow chambers 31, 30 while the connecting passage 8 forms a separate through flow connection 32, 33 respectively to the two through flow chambers 30, 31. The two second through flow connections 33 and 32, when at rest, are occluded by small pressure-actuating surfaces 21, 22 on the throttle members 11, 12. Inside the through flow chambers 31, 30, large pressure-exposed surfaces 34, 35 are constructed on the throttle members 11, 12. The through flow connections 9 and 10 represent a resistance to flow and open out into annular spaces 36, 37 on both sides of the separating piston 7. The separating piston 7 is provided with a separating piston gasket 7a which is disposed in the region of a thickened portion 7b of the separating piston and bears on an inner peripheral surface 3c of the cylinder 3. Adjacent the throttle member accommodating chambers 15, 16 are extension chambers 38, 39 in which thickened portions 40, 41 of the piston rod 4 or of a piston rod extension 25 are housed and fixed. The throttle member accommodating chambers 15, 16 are closed in sealing-tight fashion by flanged-over portions 42, 43 and by the use of sealing elements 17 to 20. The piston rod 4 is guided in sealing-tight manner through one end 44 of the cylinder 3, a gasket 45 being incorporated, while the piston rod extension 25 is guided in sealing tight manner through a floating partition 46, a gasket 26 being employed. The floating partition 46 is restricted in its upwards movement by an indentation 48 in the cylinder 3 and is initially tensioned upwardly by a coil thrust spring 27, this latter being biased through a bracing disc 49 against a further indentation 50 of the cylinder 3. The space below the floating partition 46 is filled for instance with air at atmospheric pressure. Braced against the end wall 44 is a rubber-elastic end support 52. The attachment point 2 is constituted by two journals 2a and 2b which may for instance be pivotally mounted on the body work of a motor vehicle. The attachment point 1 is constituted by a screw thread on the piston rod 4 which can for instance be supported on the door of a motor vehicle. It is also conceivable to mount the attachment point 2 at the bottom end of the cylinder 3 or at any desired location along the cylinder 3. Fitted at the top end of the cylinder 3 is a switch 53 which co-operates with a switching element 54. The switching element 54 is fixed on the piston rod 4 and acts on the circuit of the switch 53. The circuit can for instance be the circuit for the interior lighting of a vehicle, so that this interior lighting is switched on when the door of the vehicle is opened and in consequence the piston rod 4 is extended upwardly out of the cylinder 3. When the piston rod is completely extended out of the cylinder 3, the flanged-over part 43 of the separating piston 7 strikes the rubber-elastic abutment 52 and so dampens the movement of the door before this latter has reached its extreme and farthest open position. It can be seen that the separating piston 7 is formed by a one-piece separating piston member comprising an intermediate wall 7c and two extensions 7e and 7f. The coil thrust springs 13, 14 are accommodated by bores 13a and 14a in the piston rod 4 and piston rod extension 25. The coil thrust springs 13, 14 are, prior to fitment, substantially longer than shown in FIG. 1 and during assembly they are compressed to such an extent that they exert the particular desired pretensioning force on the throttle members 11 and 12. The cylinder 3 is provided with a by-pass path 3d which is formed outwardly by an elongate bulge on the cylinder 3. The locking device as it has been described so far works as follows: let it be assumed that the locking device is articulatingly connected to the body work of a motor vehicle at one end and to a door at the other, at locations 2 and 1 respectively. Let it be further assumed that the door is completely closed and that the condition of the locking device shown in FIG. 1 corresponds to the door when closed. If, now, the door is opened, then the gasket 7a of the separating piston 7 firstly moves in the region of the by-pass 3d so that the two working chambers 5 and 6 are initially still connected to each other and therefore the locking device is ineffective. If, then, during further progress of the movement to open the door the gasket 7a travels beyond the end of the by-pass 3d, then the two working chambers 5 and 6 are isolated from each other hydraulically at first and a hydraulic over-pressure builds up in the liquid enclosed in the working chamber 5. This hydraulic over-pressure in the working chamber 5 is applied to the through flow chamber 31 via the annular gap 36 and the first through flow connection 9. Therefore, it acts on the larger pressure actuated surface area 34 of the throttle member 11 against the action of the pretensioning spring 13. As soon as the over-pressure in the through flow chamber 31 exceeds a predetermined value, the throttle member 11 is, against the action of the pretensioning spring 13, lifted off the second through flow connection 33 which is formed by the connecting passage 8 in the intermediate wall 7c. This means that now the pressure inside the through flow chamber 31 also bears on the smaller working surface 22 of the lower throttle member 12, against the action of the lower pretensioning spring 14. The pressure which was sufficient to lift the upper throttle member 11 by acting on the larger working surface 34 is not sufficient also to lift the lower throttle member 12 off the through flow connection 32 of the associated through flow chamber 30. Instead, by reason of the force acting on the door and thus on the locking device according to FIG. 1, a further increase in pressure in the working chamber 5 is needed so that the throttle member 12 can be lifted off the associated through flow connection 32. The necessary increase in pressure depends thereby upon the size of the small pressure-exposed surface area 22 which is exposed to the pressure in the passage 8. As soon as the pressure in the passage 8 has risen sufficiently that the lower throttle member 12 lifts downwardly off the associated through flow connection 32, fluid is able to flow from the working chamber 5 through the through flow connection 9, the through flow chamber 31, the through flow connection 33, the passage 8, the through flow connection 32, the through flow chamber 30, the through flow connection 10 and the annular gap 37 to the second working chamber 6. When this happens, a drop in pressure occurs in the through flow connection 10. By reason of this pressure drop, an above-atmospheric pressure is obtained in the through flow chamber 30. This over-pressure acts on the larger pressure-exposed surface 35 of the throttle member 12 so that this throttle member is held in the open position in respect of the through flow connection 32, so long as there is a relative movement of the piston rod 4 in relation to the cylinder 3. Due to the action of the pressure on the large pressure-exposed surface 35 of the throttle member 12, a relatively small over-pressure in the through flow chamber 30 is sufficient to maintain the throttle member in the lifted-off position in respect of the through flow connection 32, so maintaining a through flow from the working chamber 6. In short, this has the following significance: once the throttle member 12 has been initially lifted off the through flow connection 32 by force acting on the door at a comparatively marked extent so that the through flow from the working chamber 5 to the working chamber 6 has been initiated, further movement of the door in the direction of the fully open position of the door requires comparatively little effort in order to maintain the throttle member 12 in the open position in comparison with the through flow connection 32, i.e. relatively minimal force is needed in order to move the door farther in the direction of the fully open position so long as the speed of movement is kept sufficiently great that the drop in pressure at the through flow connection 10 and the pressure in the through flow chamber 30 dependant upon this pressure drop is sufficient to maintain the throttle member 12 in the lifted-off position with respect to with the through flow connection 32. Only if the speed of movement of the door and thus of the piston rod 4 in relation to the cylinder 3 becomes nil or so slow that the pressure in the through flow chamber 30 diminishes considerably does the throttle member 12 return to the position shown in FIG. 1. Then the door is arrested in any desired midway position which means it can only be set in motion again if a considerable pushing force is exerted on the door and thus on the piston rod 4, a pushing force which is great enough that, according to the direction of movement, one or other of the two throttle members 11, 12 is again lifted off the associated through flow connection 33, 32. The completely symmetrical design of the piston 7 readily shows that the mode of operation described hereinabove to cover the opening of a door is also valid when the door is closed in which case, then, the over-pressure will naturally build up in the working chamber 6 first and initially cause the throttle member 12 to lift off the through flow connection 32 so that then, with a corresponding increase in the pushing force acting on the door, the throttle member 11 lifts off the through flow connection 33 and remains lifted off because once lift-off has occurred, the pressure prevailing in the through flow chamber 31 due to the drop in pressure at the through flow connection 9 acts on the larger pressure-exposed surface 34 of the throttle member 11. FIG. 1 further shows that when the door again moves towards the closed position, the gasket 7a moves into the region of the by-pass 3d again. Then there is no longer a hydraulic force counteracting the further closing movement of the door. On the rest of the way until it is completely closed, the door can then be accelerated sufficiently by hand that its movement impulse which results is sufficient to cause the door to snap into the door lock against the resilient resistance which the door lock offers to prevent this snapping engagement. Since the piston rod 4 and the piston rod extension 25 are of the same diameter, the total of the spaces in the two working chambers 5 and 6 does not change when there is a displacement of the piston rod 4 relative to the cylinder 3. Therefore, it is only necessary to take into account those fluctuations in the volumes of liquid contained in the two working chambers 5 and 6 which may arise due to temperature expansion or contraction of the fluid and/or such changes in these volumes of liquid which may occur due to leakage losses through the gaskets 45 and 26. To this end, the movable partition 46 is initially tensioned by a spring 27 in the direction of the indentation 48. A strong coil thrust spring 27 is adjusted to such a spring force that under normal working conditions this spring is not substantially compressed when the piston rod 4 is retracted into the cylinder 3. For this purpose, care must be taken that when retracting the piston rod 4, the pressure in the through flow chamber 31 needed to lift the throttle member 11 off the through flow connection 33, in consequence of a pressure in the working chamber 6, is at a level which is not sufficient to displace the partition 46 against the action of the coil thrust spring 27. It has been assumed hitherto that the pressure-exposed. surfaces 21 and 22 are of the same area and that also the pressure-exposed surfaces 34 and 35 are identical to each other. This means that regardless of the direction of displacement of the piston 4 in relation to the cylinder 3 the pushing force needed to initiate the movement and also the resistance counteracting further movement are in each case the same. It can be readily appreciated that the small pressure-exposed surfaces 21 and 22 may differ from each other and that also the large pressure-actuated surfaces 34 and 35 can be made different from each other. Asymmetrical force relationships then arise and in some cases this may be desired. The embodiment according to FIG. 2 differs from that shown in FIG. 1 in that the piston rod extension 25 according to FIG. 1 has been replaced by a plug 125 which just like the piston rod extension 25 in FIG. 1 is housed and sealed in the piston body and also accommodates as part of the pretensioning spring 114. As a working medium in the two working chambers 105 and 106 it is again possible to use a liquid. The working chamber 106 is sub-divided by a partition 160. This partition 160 comprises a first group of bores 161 with a closure spring 162. The closure spring 162 is a hard or a hard pretensioned closure spring. Furthermore, the partition 160 comprises a valve bore 163 with a soft or softly pretensioned closure spring 164. If the piston rod 104 is withdrawn from the cylinder 103, possibly as the result of the opening of a door, then the total volume in the working chambers 105 and 106 becomes greater. Under the action of a separating piston 165 and a coil thrust spring 166, fluid then flows out of the partial working chamber 106a into the partial working chamber 106b, only negligible resistance being offered to this secondary flow through the bore 163. The force to initiate movement of the piston rod 104 out of the cylinder 103 is substantially unchanged in relation to the embodiment shown in FIG. 1, subject to the valves being the same size. In particular, the force for initiating an outwards movement of the piston rod 104, in other words the force for stabilising the door, remains substantially unchanged. On the other hand, if the piston rod is exposed to a downwardly directed force, possibly to prepare for closing of a door, then the pressure in the partial working chamber 106b initially rises. This pressure initially produces a lifting of the throttle member 112 off the through flow connection 132. Then, when the pressure in the partial working chamber 106b continues to rise, then also the throttle member 111 is lifted off the through flow connection 133. This lift off takes place before the strong valve spring 162 is lifted off the valve bore 161. This means that the force needed to lift the throttle member 112 off the through flow connection 132 is again the same as with the embodiment in FIG. 1 so that stabilising of the door is unchanged and is equally good in the direction of closure. If, now, the piston rod 104 is retracted into the cylinder 3, then the closing force of the valve spring 162 must be overcome since the piston rod 104 increasingly displaces volume inside the cylinder. Furthermore, the end wall 165 must be displaced downwardly against the action of the coil thrust spring 166. Due to the need to open the valve spring 162 and push the end wall 165 downwardly, there is an additional resistance to the piston rod 104 being pushed in. However, since this piston rod 104 is now of comparatively small cross-section compared with the total cross-section of the separating piston 107, the volume displacement by the valve 161, 162 per unit of length of displacement of the piston rod 104 is relatively slight and in the same way the displacement path of the end wall 165 per unit of length of the displacement of the piston rod 104 is comparatively slight. The additional resistance to movement can consequently be so reduced by minimal cross-sectional dimensioning of the piston rod 104 that it produces only an inconsiderable change in the mode of action of the locking device according to FIG. 2 in comparison with that according to FIG. 1. The embodiment shown in FIG. 3 differs from that in FIG. 2 only in that the coil thrust spring 166 has been replaced by a pressurized gas volume 266. The advantage of this embodiment resides in the fact that the spring force of the pressurized gas volume can easily be changed by appropriate filling. FIG. 4 shows a further embodiment, parts which are identical being provided with the same reference numerals as in FIGS. 1, 2 and 3 but increased by 300 and 200 or 100 respectively. Inserted into the cylinder 303 from the top end, through the end wall 333 and the gasket 345 is a slideable piston rod 304 which carries at its top end a hinge lug 301. Constructed inside the cylinder 303 are the two working chambers 305 and 306 which together form a cylindrically tubular cavity 305, 306. The lower working chamber 306 is divided by the partition 460 into two partial working chambers 306a and 306b. The working chamber 305 is separated from the upper partial working chamber 306b by the separating piston unit 307. The separating piston unit 307 is constructed in the same way as the bottom half of the separating piston unit 7 in FIG. 1. The working chamber 305, the two partial working chambers 306b and 306a are filled with liquid. The floating partition 365 separates the lower partial working chamber 306a from a space 366 filled with pressurized gas. Accommodated in the separating piston unit 307 is a sealing piston 312 which corresponds to the throttle member 12 in FIG. 1. This sealing piston 312 is sealed in respect of the inner peripheral surface of a space 316 by a gasket 319. Defined above the sealing piston 312 is a through flow chamber 330. This through flow chamber 330 comprises a first connection 332 corresponding to the through flow connection 32 in FIG. 1. Via an axial bore 308 and a radial bore 308a, this first connection 332 is substantially adjacent the upper working chamber 305 with no throttle in between. A second connection 310 corresponds to the through flow connection 10 in FIG. 1 and connects the through flow chamber 330 to the partial working chamber 306b. It must be ensured that in any position of the sealing piston 312, the second connection 310 is disposed inside the space 316 above the gasket 319 so that the through flow chamber 330 is constantly in communication with the partial working chamber 306b, the cross-section of the second connection 310 being narrow and forming a throttle point the significance of which will be dealt with later. In the position shown in FIG. 4, the sealing piston 312 is applied by the coil thrust spring 314 against the first connection 332 in a sealing-tight manner so that the through flow chamber 330 is separated from the upper working chamber 305. Furthermore, it is important to ensure that in the situation shown in FIG. 4 the fluid filling of the upper working chamber 305 bears via the bores 308 and 308a on a small fluid-exposed cross-section 322 of the sealing piston 312 and that a larger fluid-exposed cross-section 335 is exposed to the pressure inside the through flow chamber 330. The partition 460 in its basic effect corresponds to the partition 160 in FIG. 2 but, in contrast to the embodiment of partition 160 in FIG. 2, it is constructed in a manner similar to that of the separating piston unit 307. The partition 460 is axially fixed in the cylinder by deformation of the cylinder 303 in respect of which it is sealed. Identical parts of the partition 460 are identified by the same reference numerals as the corresponding parts of the separating piston unit 307 but furthermore raised by 100. Furthermore, a non-return valve which opens from the partial working chamber 306a into the partial working chamber 306b is constructed on the partition 460. Forming part of this non-return valve are bores 463. These bores are masked by a valve plate 464 which is in turn overlaid by a plate spring 464a so that the valve plate 464 is maintained in the closed position with a small amount of pretension. The mode of operation then is as follows: in FIG. 4, the piston rod 304 is locked in respect of the cylinder 303. If the total length of the cylinder piston unit 303, 304 is to be extended, then a traction force must be applied to the hinge lug 301 and the hinge lug 302b. Then the pressure in the upper working chamber 305 increases. This increased pressure is now applied to the small fluid-exposed cross-section 322 via the bores 308 and 308a. By virtue of the small size of the fluid-exposed cross-section 322, a relatively considerable increase in pressure in the working chamber .305, i.e. a relatively great tractive force on the hinge lug 301, is required in order to cause the sealing piston 312 to be lifted off the first connection 332. The design and pretension of the coil thrust spring 314 determines the pressure which has to be built up in the working chamber 305 by traction exerted on the hinge lug 301 in order to cause the sealing piston 312 to be lifted off the first connection 332. Therefore, it is necessary to apply a relatively considerable "break-free force" to the hinge lug 301 in order to initiate an extraction movement of the piston rod 304. Once the sealing piston 312 has lifted off the first connection 332, then there is a flow of fluid from the working chamber 305 through the bores 308a and 308, the first connection 332, the through flow chamber 330, the second connection 310 and the annular channel 337 in the direction of the upper partial working chamber 306b. Attention has already been drawn to the fact that the bore constituting the second connection 310 is constructed as a throttle. If, now, fluid flows from the upper working chamber 305 to the upper partial working chamber 306b, then there is a pressure drop at the throttling bore 310. Then, an intermediate pressure is established in the through flow chamber 330 which is indeed less than the pressure built up in the upper working chamber 305 by the tractive effect, but it is still considerably greater than the pressure in the partial working chamber 306b and great enough to overcome the force of the spring 314 and any pressure in the chamber 316. This intermediate pressure in the through flow chamber 330 now acts on the large fluid-exposed cross-section 335 of the sealing piston 312. Therefore, all in all there is now increased pressure on the entire upper surface of the sealing piston 312 constituted by the sum of the small fluid-exposed cross-section 322 and the large fluid-exposed cross-section 335. Thus, the sealing piston 312 is now maintained in a position in which it is lifted off the first connection 332, even if the fluid pressure in the upper working chamber 305 should fall again. This means that--once the first connection 332 has been opened once--a relatively minimal pull on the hinge lug 301 is sufficient to withdraw the piston rod 304 and so further increase the total length L. Applied to the case of a motor vehicle door, once again this means that after a pushing force which is sufficient to lift the sealing piston 312 off the first connection 332, a relatively small amount of effort is needed in order to open the door farther (subject to an opening of the door corresponding to an increasing of the length L while closing the door corresponds to a shortening of the length L). Therefore, after briefly exerting an opening pushing force on the motor vehicle door, this can be opened farther with minimum effort. cross-section When one is approaching a desired new open position of the door, the opening movement of the door which is performed manually can be slowed down to zero speed. Accordingly, the rate of liquid flow out of the working chamber 305 into the partial working chamber 306b diminishes. Then also the pressure drop in the second connection 310 abates and the pressure in the through flow chamber 330 approximates more and more the pressure in the partial working chamber 306b. In the case of an intermediate pressure determined by construction and pretension of the coil thrust spring 314 and by the dimensioning of the small fluid-exposed cross-section 322 and the large fluid-exposed cross-section 335, this intermediate pressure is no longer sufficient to maintain the sealing piston lifted off the first connection 332 which is then closed again. The piston rod 304 is thus arrested again in the direction of being pushed out in respect of the cylinder 303, until once again a pushing force is applied in order to open the door farther if required. If in the case of the aforedescribed pull-out movement of the piston rod 304 in respect of the cylinder 303 the piston rod length remaining inside the cylinder 303 becomes shorter, then there is an increase in the space composed of the sum of the working chamber 305 and upper partial working chamber 306b. Therefore, in the absence of additional measures in the two chambers 305 and 306b, the liquid contained prior to commencement of the movement of pulling out the piston rod 304 would no longer be sufficient completely to fill the two chambers, working chamber 305 and partial working chamber 306b. Then, the piston rod would have play in its movement. This is prevented by the aforedescribed construction of the partition 460. If, namely, there is an increase in volume in the upper partial working chamber 306b due to extension of the piston rod 304, then also the pressure prevailing in the partial working chamber 306b is reduced. Then the pressure prevailing in the lower partial working chamber 306a can easily open the non-return valve 464 in keeping with its slight pretension and liquid is able to flow from the lower partial working chamber 306a into the upper partial working chamber 306b, the floating wall 365 moving upwardly under the pressure of the gas volume 366. It has been pointed out hereinabove that the piston rod 304 can be set in motion from being stationary but only with the application of a relatively considerable pushing force. This is desirable because, for instance in the case of a motor vehicle door, this door cannot be regularly opened by wind force or by an unintended push from the driver. It will be demonstrated hereinafter that also an unintentional shortening of the total length L cannot easily be effected by pushing in the piston rod 304. When the piston rod 304 is pushed into the cylinder 303, the non-return valve 464 is acted upon in the direction of closure by the pressure prevailing in the working chamber 306b and it does not allow any fluid to pass from the partial working chamber 306b into the partial working chamber 306a. Pushing in the piston rod 304, then, initially leads to an increase in the pressure in the upper partial working chamber 306b. At the onset of pushing in, the upper partial working chamber 306b is separated from the upper working chamber 305 because, in keeping with its inoperative state, the sealing piston 312 bears in sealing-tight manner on the first connection 332 so that no liquid is able to pass from 306b to 305. Increasing the pressure in the partial working chamber 306b, however, means that the larger fluid-exposed cross-section 335 is acted upon by liquid via the bore 310. Therefore, a relatively minimal pressure is sufficient to open the first connection 332 and initiate a transfer of liquid from the upper partial working chamber 306b into the upper working chamber 305. This means that theoretically only a minimal resistance to push-in counteracts pushing of the piston rod 304 into the cylinder 303. However, pushing the piston rod 304 in entails an increase in the volume displaced by the piston rod 304 inside the cylinder 303. In order to be able to compensate for this reduction in volume in the two working chambers 305 and 306b together, fluid has to be moved from the upper working chamber 306b into the lower partial working chamber 306a. Since the non-return valve 464 is not available for this, all that remains is the way via the first connection 432, the through flow chamber 430, the second connection 410 and the annular passage 437. However, in order to make this way available, it is necessary first to lift the sealing piston 412 off the first connection 432 and for this purpose, on account of the small size of the fluid-exposed- cross-section 422 with corresponding design and initial tension of the coil thrust spring 414, a relatively high pressure is required in the upper partial working chamber 306b. Therefore, when pushing in of the piston rod 304 into the partial working chamber 306b starts, a relatively high pressure has to be generated so that the sealing piston 412 lifts off the first connection 432. Once this lifting off process is completed, there is a flow of liquid from the partial working chamber 306b into the partial working chamber 306a corresponding to the increasing immersion of the piston rod 304 into the cylinder 303. Once again, there builds up in the through flow chamber 430 an intermediate pressure which acts to lift the sealing piston 412 off the first connection 432 so that subsequently the sealing piston 412 can also be maintained open with a reduced pressure in the partial working chamber 306b. This means that once the piston rod has been set in motion, it can be pushed farther in with a relatively minimal application of pressure to the hinged lug 301. This pushing in movement counteracts the through flow resistance through the bore 310 and the first connection 332. However, this through flow resistance is relatively minimal because of course the sealing piston 312 is, in this stage of the operation, again being acted upon at the large fluid-exposed cross-section 335. Furthermore, the pushing in movement counteracts the through flow resistance from the partial working chamber 306b to the partial working chamber 306a. But even this through flow resistance can be minimized because once the movement to push in the piston rod 304 has been initiated, the pressure which builds up in the partial working chamber 306b acts on the large fluid-exposed cross-section 445 of the sealing piston 412. Finally, pushing of the piston rod 304 into the cylinder 303 is also counteracted by the gas volume 366 which has to be compressed upon the flow of liquid into the lower working chamber 306a with a downwards movement of the floating partition 365. This compression force is however relatively small and this is a particular advantage of the aforedescribed design: were the partition 460 not present and if it were necessary to build up a high degree of pressure in the upper working chamber 306b in order to open the first connection 432, then it would only be possible to provide an adequate push-in resistance which is necessary for instance to prevent the unintentional closure of a motor vehicle door, by imposing a correspondingly high pressure on the gas volume 366. This high pressure would however mean that when it was intended to close the motor vehicle door over its entire closure path, it would be necessary to apply a considerable force to the door by hand. This is not intended. It is far more the wish of the motor vehicle proprietor to be able easily to move the door, also in the direction of closure, after the brief application of a pushing force and as described hereinabove, this is achieved by the embodiment according to FIG. 4. The low pressure of the gas volume 366 also has the advantage that pushing out the piston rod 304 is not substantially assisted by the piston-cylinder unit. In many cases, particularly in the case of a vertical pivoting axis of a motor vehicle door, such assistance is not desired since it might lead to the door opening rapidly. However, it is not intended either to exclude the possibility of the gas pressure being used to assist door opening, possibly when the pivot axis of the motor vehicle door is in a corresponding inclined attitude and a closing moment is generated in a direction of closure by the actual weight of the door. It is possible to compensate for such a closing moment by appropriate dimensioning of the gas pressure in the gas volume 366. It must also be pointed out that the gas volume 366 which acts on the floating partition 365 can also be replaced by a coil thrust spring. It must also be pointed out that the compensating volume for the variable displacement volume of the piston rod which is provided at the bottom end of the cylinder 303 by the floating partition 365 in FIG. 4 can also be formed at the upper end of the cylinder 303, possibly in that a volume of gas is incorporated beneath the gasket 345. It must be anticipated that the piston-cylinder unit can also be used horizontally or upside down. Therefore, it is recommended to provide an annular floating partition which then separates the volume of gas at the top end of the cylinder 303 from the liquid in the working chamber 305. In this case, too, the volume of gas could once again be replaced by a coil thrust spring. FIG. 5 shows a gas spring which substantially corresponds to the principles of design shown in FIGS. 1 to 4. Identical parts are identified by the same reference numerals as in the preceding drawings, but in each case they have an initial digit of 5. In this embodiment, once again the separating piston unit 507 with a hollow piston member is rigidly mounted on the piston rod 504 and, via the gasket 507a, it separates the two working chambers 505 and 506 from each other. The hollow piston member is designated 507b and is rigidly fixed to the piston rod. Accommodated in displaceable fashion in the hollow piston member 507b is a sleeve member 570 which, in the space 316, accommodates the sealing piston 512 which is constructed in exactly the same way as in the previously described embodiments and it is accordingly designated 512. The sleeve member 570 forms below a gasket 571 an annular gap 579 with the inner peripheral surface of the hollow piston member 507b. The through flow chamber 530 with the first connection 532, the second connection 510, the gasket 519, the large fluid-exposed cross-section 535, the small fluid-exposed cross-section 522 and the bore 508 is constructed in exactly the same way as the corresponding parts in the preceding drawings, which is expressed by conformity of the last two digits in the respective reference numerals. In contrast to the preceding embodiments, the side of the sealing piston 512 which is remote from the first connection 532 is exposed to the pressure in the lower working chamber 506 plus the spring force of the coil thrust spring 514. The sleeve member 570 on the one hand assumes the function of a fluid guide member and on the other the function of a non-return valve member. It is pretensioned into the position shown in FIG. 5 by a coil thrust spring 572 which maintains the sleeve member 570 bearing against a bracing shoulder 507c, through an annular disc 573 against which the coil thrust spring 514 is biased, said annular disc 573 being possibly fastened to said sleeve member 570. The non-return valve to which the sleeve member 570 belongs is generally designated 574. This non-return valve 574 includes a step 575 on the inner peripheral surface of the hollow piston member 507b and a radial bore 576 which connects a non-return valve chamber 577 to the upper working chamber 505. This embodiment which is shown in FIG. 5 behaves in a very similar manner to the previously described embodiment shown in FIG. 4. When the piston rod 504 is pulled upwardly out of the cylinder 503, an increased pressure builds up in the upper working chamber 505. This increased pressure acts through the bore 576 and the bore 508 on the small fluid-exposed cross-section 522 of the sealing piston 512. Upon commencement of the outwards movement of the piston rod 504, there is once again need for a relatively high pressure in the working chamber 505 and thus in the bore 508 so that despite the small fluid-exposed cross-section 522 the sealing piston 512 lifts off the first connection 532 of the through flow chamber 530. Once this lifting off process has taken place, the increased pressure inside the upper working chamber 505 which is created by the pull out force applied to the piston rod 504 also acts on the larger fluid-exposed cross-section 535 of the sealing piston 512 as a result of the pressure drop in the second connection 510, so that upon continued outwards movement of the piston rod 504, the sealing piston 512 also remains lifted off the first connection 532 if the pressure in the upper working chamber 505 becomes reduced again. Therefore, as with all the preceding embodiments, there is also here an element in which, in order to initiate a movement of the piston rod, a relatively considerable pushing force is needed and afterwards the pull out movement can be continued with just a minimal pull out force. When the speed at which the piston rod 504 is being pulled out in relation to the cylinder 503 comes close to ZERO, then the pressure on the larger fluid-operated cross-section 535 becomes so small that it can no longer maintain balance between the pressure of the coil thrust spring 514 and the pressure of the gas volume in the lower working chamber 506. Consequently, the first connection 532 closes again and movement of the piston rod 504 comes to a standstill. Upon an inwards displacement of the piston rod 504 in respect of the cylinder 503, the non-return valve 574 opens. A relatively minor increase in pressure in the lower working chamber 506 is sufficient to move the sleeve member 570 upwardly. The increased pressure in the working chamber 506 namely acts on the back of the sealing piston 512; this is moved upwardly with respect to the separating piston unit 507 and, with continued closure of the first connection 532, entrains the sleeve member 570 upwardly until such time as the gasket 571 has slipped over the step 575. Then gas is able to flow out of the lower working chamber 506 through a notch 578, the annular space 579, the chamber 577 and the bore 576 and into the upper working chamber 505. The particular feature arising from the gas filling and a push out force exerted on the piston rod 504 by this gas filling can be most easily explained with regard to an arrangement such as is shown in FIGS. 6 and 7. These drawings show a motor vehicle body 580 and a tailgate 581 is articulated on the body 580 at 582. FIG. 6 shows the closed position of the tailgate 581 in solid lines while the broken lines indicate the fully opened position. FIG. 7 shows the tailgate in an intermediate position. A cylinder-piston unit 503, 504 of the type shown in FIG. 5 is articulated on the tailgate 581 at 585 and on the body work 580 at 586. Two such piston-cylinder units may be disposed parallel, for instance one on each of the two longitudinal boundary walls of the body work. For purposes of the ensuing description of operation, it is assumed that a single piston-cylinder unit is provided. If there are two such piston-cylinder units, the situation changes only in that in such a case each of these piston-cylinder units only has to apply half the lift assistance and arresting forces. Firstly, FIG. 7 will be examined in conjunction with FIG. 5 and initially it is sufficient to establish that the push out force exerted on the piston rod 504 by the pressure of gas inside the cylinder 503 is basically capable of further raising the tailgate 581 from the position shown in FIG. 7 without any manual aid. When examining FIG. 5, it is further assumed that the piston rod 504 is stationary. The first connection 532 is closed, the non-return valve 574 is likewise closed. There is no connection between the two volumes of gas in the working chambers 505 and 506. The tailgate 581 which is adapted to pivot about the hinge axis 582 suffers, by reason of its own weight, a turning moment about the hinge axis 582 and this seeks to close the tailgate 581 and exerts on the piston-cylinder unit 503, 504 a force which seeks to push the piston rod 504 into the cylinder 503. According to FIG. 5, in a position corresponding to FIG. 7, there is in the lower working chamber, also referred to as the end chamber, a pressure P1 while there is a pressure P2 in the upper working chamber 505, also referred to as the rod chamber. The pressure P1 acts on the full cross-section of the separating piston unit 507 which is designated Q1. The pressure P2 acts on an annular cross-section Q2 which constitutes the difference between the cross-section Q1 and the cross-section Q3 of the piston rod 504. Furthermore, there acts on the piston rod 504 a weight force FG determined by the weight of the tailgate 581 and the position of the articulation points 582, 585 and 586. In the state of equilibrium, the following equation is virtually applicable: P1×Q1=P2×Q2+FG. In this case, in the state of equilibrium, the pressure P2 is greater than the pressure P1. The pressures P2 and P1 both of which engage the sealing piston 512 are thereby, also taking into account the coil thrust spring 514, so adjusted that the sealing piston 512 does not lift off the first connection 532. For the rest, the pressures P1, P2 are so adjusted that, taking into account the springs 514 and 572, the sleeve member 570 retains its position assumed in FIG. 5 and the non-return valve 574 is therefore closed. Let it further be assumed that the user of the motor vehicle wishes further to open the tailgate 581 in relation to the position shown in FIG. 7, in the direction of complete opening as indicated by the broken lines in FIG. 6. To do this, the user applies a lifting force FH by hand to the tailgate 581. This lifting force produces a force which seeks to pull out the piston rod 504. This pull-out force alters the equilibrium so that the pressure P2 in the working chamber 505 increases. This increase in pressure in the upper working chamber 505 means that there is also a rise in pressure on the small fluid-exposed cross-section 522. As a result of this rise in pressure, the sealing piston 512 is lifted off the first connection 532. In order to make it possible also for weak users of the vehicle to lift the sealing piston 512 off the first connection 532, a corresponding disposition and design of the piston-cylinder unit which is constructed as a gas spring ensure that even at a lifting force FH of less than 100N and preferably at a lifting force FH of less than 50N, the increase in gas pressure P2 in the upper working chamber 505 is sufficient to cause the sealing piston 512 to be lifted off the first connection 532. If, now, the sealing piston 512 is lifted off the first connection 532, then there is a flow of gas from the upper working chamber 505 to the lower working chamber 506 following the route 576, 577, 508, 530, 510, 579, 578. The direction of flow, as already mentioned above, arises from the fact that the pressure P2 in a state of equilibrium is greater than the pressure P1. In the case of this flow from the working chamber 505 to the working chamber 506, as already explained in detail in the aforedescribed embodiments, there is a pressure drop at the second connection 510. The effect of this pressure drop is that an intermediate pressure PZ is established in the through flow chamber and is greater than the pressure P1. This intermediate pressure PZ acts then on the larger fluid-exposed cross-section 535 and ensures that the sealing piston 512 remains lifted off the first connection 532 even if the increase in pressure P2 in the upper working chamber 505 brought about temporarily by the application of the lifting force FH is cancelled again. Once the sealing piston has been lifted off the first connection 532 and is maintained open by virtue of the action of the intermediate pressure PZ, then the piston rod 504 can be pushed automatically out of the cylinder 503, lifting the tailgate 581. It is only necessary to ensure that the push-out force exerted on the cross-section Q1 by the pressure P1 is greater than the sum of the force exerted by the pressure P2 on the cross-section Q2, the weight force FG and the resulting resistance to through flow from the working chamber 505 to the working chamber 506. Certainly, it is important to remember that the push-out movement of the piston rod 504 occurs at the speed which is sufficient to maintain the intermediate pressure PZ at the larger fluid-operated cross-section 535 above the level needed to maintain the sealing piston 512 lifted off the first connection 532. The dimensions in the gas spring 504, 503 needed to satisfy these conditions can easily be arithmetically and/or experimentally ascertained by a man skilled in the art, in the light of the tailgate weight and the articulation points 582, 585, 586. Once these conditions have been satisfied, therefore, when one wishes to raise the tailgate 581 in relation to the inoperative position shown in FIG. 7, it is necessary only to exert a brief and relatively minor lifting force FH on the tailgate and then the tailgate will rise by itself until it is again arrested or until the tailgate 581 has reached the position of maximum opening shown in FIG. 6, which is determined by abutments between body work and tailgate or by an abutment of the separating piston unit 597 against the abutment ring 590. If it is desired to arrest the upwards movement of the tailgate 581 before it has reached the highest position shown in FIG. 6, this can be achieved by briefly and manually applying a depressing force to the tailgate as shown in FIG. 7. The following then happens: the speed of extension of the piston rod 504 is reduced and consequently the intermediate pressure PZ in the through flow chamber 530 drops and is no longer sufficient to keep the sealing piston 512 lifted off the first connection 532. In this way, the sealing piston 512 occludes the first connection 532; the working chambers 505, 506 are again isolated from each other; the piston rod 504 remains stationary in relation to the cylinder 503; the tailgate 581 has reached a fresh midway position. This new intermediate position is subject to the same considerations raised hereinabove for the intermediate position shown in FIG. 7. At this point, it should be noted that by corresponding calculation or experimentation, it is again possible to choose such a dimensioning of the piston-cylinder unit and of its installation conditions that only a relatively minor depressing force FN is needed to arrest the upwards movement of the tailgate. Preferably, care will be taken to ensure that this depressing force FN is less than 100N and preferably less than 50N. Once this depressing force FN has been briefly applied, the tailgate remains in the position reached and is at rest, as shown in FIG. 7, even when the depressing force FN is removed from the tailgate 581. With regard to the magnitude of the raising force FH and the depressing force FN, only the upper limit values have been indicated hereinabove, in consideration of the fact that also a weak person is able to apply these forces. Nevertheless, it should be mentioned that these forces FN and FH ought not to be reduced willy nilly. They ought to be sufficiently great that accidental pushing of the tailgate or wind forces cannot give rise to unintended movements. On a basis of the situation shown in FIG. 7, if it is desired to lower the tailgate in the direction of closure, as indicated by solid lines in FIG. 6, then it is necessary to apply a lowering force FS to the tailgate as shown in FIG. 7. Then the pressure P1 in the working chamber 506 increases and this increased pressure acts on the sealing piston 512 and the sleeve member 570. As a result of this increased pressure, the sleeve member 570 together with the sealing piston 512 is displaced upwardly in FIG. 5 until the sealing ring 571 has passed beyond the stop 575 on the inside face of the space 577. A through flow facility from the working chamber 505 is then opened up via 578, 579, 577, 576 toward the working chamber 505. In this situation the lowering force FS must be continued over the entire intended lower path. However, it is also possible arithmetically or experimentally to achieve such a dimensioning of the gas spring in the light of the tailgate weight and the disposition of the articulation points 582, 585, 586 that also the lowering force FS needed to lower the tailgate takes into account the needs of a weak person and is in particular no greater than 100N and preferably no greater than 50N. It can readily be seen from FIG. 7 that during the course of a movement which pivots the tailgate 581, the situation is constantly changing. These changes must naturally be taken into account also when dimensioning the gas spring so that the aforedescribed conditions and processes are virtually applicable at all points along the pivoting path. When the tailgate comes close to the closed position shown in solid lines in FIG. 6, it is often not required that the tailgate should then be maintained in a midway position by the gas spring nor is it then any longer necessary for raising of the tailgate to be assisted by the gas spring. In a short portion of the pivoting range prior to the closure position, midway positions are in fact unnecessary because in practice such intermediate positions are hardly ever needed. In this borderline area adjacent the closed position, assistance of tailgate raising is not even desirable because having regard to the conventional lock structures it is necessary when approaching the position of closure to accelerate the tailgate movement in order to ensure that the lock engages with a snap action. The aforedescribed effect of automatic closure can be limited to a range of movement which in FIG. 7 extends substantially from point I to point II, according to the position of closure. Within this range of movement I, II, then, one then has to apply a force to open the tailgate and no intermediate positions can be established. Thus, on the one hand, consideration is given to the individual needs of persons of small stature and on the other hand, the tailgate 581 can, in the range of movement from II to III, be adjusted to whatever angle of opening happens to be needed for loading or unloading relatively small or large objects. Furthermore, the tailgate can be arrested in whatever position is still acceptable for movement under obstacles, e.g. when driving through garage doors. At this point, it should also be noted that in some cases it is possible to dispense with the non-return valve 574 shown in FIG. 5 because basically the sealing piston 512 itself can serve as a non-return valve. It should be recalled that the pressure P1 in the working chamber 506 acts on the larger fluid- exposed cross-section 535 so that when the piston rod 504 is pushed in by a lowering force FS, the opening from the working chamber 506 to the working chamber 505 can also be brought about in that the sealing piston 512, as a result of the pressure P1 acting on the large fluid-exposed cross-section 535, is lifted off the first connection 532 so that there is a through flow path 578m 579, 510, 530, 508, 576. However, where calculation and design are concerned, the development shown in FIG. 5 affords a wider range of freedom which can be utilised to achieve optimum convenience for the operator. In conclusion, it should be mentioned that the separating piston unit 507 can in principle also be used in a positioning device, possibly according to FIG. 4, in place of the separating piston unit 307 which is shown therein and that also, conversely, the separating piston unit 307 shown in FIG. 4 can be used in the embodiment shown in FIG. 5 in place of the separating piston unit 507. Furthermore, it should be mentioned that the embodiment according to FIG. 5 is not necessarily tied to having only pressurized gas in the two working chambers 505 and 506. Instead, the embodiment according to FIG. 5 could also be modified to have the upper working chamber 505 filled with liquid and the lower working chamber 506 divided into a liquid-filled and a gas-filled space as shown in FIG. 4. With regard to FIG. 5, it should be added that with a corresponding dimensioning of the springs 514 and 572, the bracing disc 573 can also be axially immovably fixed on the sleeve member 570. With reference to FIGS. 5 to 7, an embodiment has been explained in which the tailgate is raised automatically by the cylinder-piston unit or units as soon as a lifting force FH has been briefly applied. Basically, it is also conceivable for a cylinder-piston unit 503, 504 to be used in order to facilitate raising of the tailgate but so to dimension the gas pressure in the cylinder-piston unit 503, 504 that the cylinder-piston unit or units only provide assistance during lifting. Nevertheless, it is possible in such a case to have an arresting facility. In this instance, the directions of through flow of the non-return valve 574 on the one hand and the through flow direction through the first connection 532 on the other can be interchanged while retaining the relationship between cylindrical tube 503 and piston rod 504 as shown in FIG. 5 in that the entire separating piston unit 507 in FIG. 5 is turned upside down so that its end which is at the bottom in FIG. 5 is applied against the piston rod 504. Then, too, a state of equilibrium is assumed when the tailgate occupies the position shown in FIG. 7. If, then, it is desired to move from the position according to FIG. 7 into a further raised position of the tailgate, then it is necessary to apply a lifting force FH over the entire lifting path, whereby the pressure relief valve 574 opens. On the other hand, starting from the position shown in FIG. 7, if it is desired to move the tailgate 581 to a lower position, then a lowering force FS must be applied in order firstly to lift the sealing piston 512 off the first connection 532. Once this opening has been achieved, the sealing piston 512 remains lifted off the first connection 532 and the tailgate will automatically lower. Even with such a solution, the forces to be applied by hand can be so dimensioned that they are within the capacity of a small person. It is further to be noted that the device as shown in FIG. 5 can also be used in a construction as shown in FIGS. 6 and 7, when the gas filling of the cylinder 503 is not sufficient to overcome the gravity of the tailgate 581 even after the sealing piston 512 has been lifted from the first connection 532. In this case, a lifting force by hand must be maintained during the total desired lifting operation of the tailgate 581. The lifting force is, however, reduced again after the sealing piston 512 has once been lifted from the first connection 532. This solution would therefore offer the advantage that when starting an upward movement of the tailgate 581, a momentarily increased lifting force is to be applied. Thus, an unintentional upward movement of the tailgate 581, e.g. by wind blow, can be avoided and, nevertheless, the upward movement of the tailgate 581 is facilitated. For downward movement it is necessary again to open the non-return valve 574 by applying a downward directed lowering force FN to the tailgate. It is further to be noted that the locking devices of FIGS. 1 to 4 can also be used in constructions of the type of FIGS. 6 and 7 for facilitating the handling of a tailgate or a trunk lid, or an engine bonnet. In case of using the device of FIG. 1 for a construction as shown in FIGS. 6 and 7, the piston rod extension 25 may be avoided and the working chambers 5 and 6 may be filled with pressurized gas. In case of FIG. 2, the partitions 160 and 165 may be avoided and the working chambers 105 and 106 may be filled with pressurized gas. While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention-may be embodied otherwise without departing from such principles.
A locking device for selectively securing two movable objects in desired positions relative to each other includes a cylinder and a piston movable within the cylinder and defining first and second working chambers of variable volumes. A fluid exchange connection provided on the piston includes a flow chamber having openings that communicate with the working chambers. A valve body slidably received on the piston in sealed relation is biased by a spring into a position closing the opening from the flow chamber to first working chamber. When the fluid pressure in the second working chamber exceeds a predetermined amount and acts on the valve body, the valve body is moved against the spring bias and opens to allow fluid to flow through the fluid exchange connection. In the open position, a larger area of the valve body is exposed to the pressure in the second chamber. A restriction in the flow path between the flow chamber and the first chamber produces a pressure drop between the flow chamber and the first chamber and allows the fluid exchange connection to remain open with a reduced pressure in the second chamber. The device thus provides for a large holding force when the valve body closes the opening and a small resistance to movement after the valve body is moved from closed. By providing two spring-biassed valve bodies acting in opposed directions, control of movements of objects in opposite directions is obtained.
4
FIELD OF INVENTION [0001] The present invention generally relates to systems for sorting individual items into groups of items. More particularly, the invention relates to systems and methods having at least two sorting steps including at least one intermediate step that sorts items into non-discrete groups. BACKGROUND OF THE INVENTION [0002] Distribution centers experience increased demands as the number of goods shipped per unit of time increases. Typically, the infrastructure of distribution centers is relatively fixed, allowing for only marginal increases in throughput capacity without substantial investment in capital improvements. [0003] For example, a distribution center may enhance throughput of existing systems by increasing the speed of conveyors and sorters, but only to a limited extent due to constraints such as conveyor belt size and strength, the momentum of moving items, and the configuration and location of sorting binds. Likewise, a distribution center may extend its operation but at substantial increase in operating costs including hours of labor and energy costs. Faced with these choices, distributors often build larger facilities to handle these increased demands. In addition to the obvious transactional costs associated therewith, including real estate acquisition and construction expenses, these bigger facilities impose larger fixed overhead costs that reduce profits, especially in times of decreased demand or fluctuations in supply. [0004] Common sorting methods include bringing disparate items to a common location where sorting functions are carried out in a series of steps. Though the precise nature of existing sorting systems may be highly individualized, they generally require a discrete destination for each group or compound group of items. These discrete destinations usually involve a chute or a bin, among others. For example, if a distribution center needs to sort items into one thousand separate “groupings” of items (also referred to as “orders”), the system may include one thousand different discrete sorting destinations. [0005] As shipping demands increase, the need for distribution centers with even greater capacity increases accordingly. The physical size of such buildings is substantial, challenging the capital resources of even the largest distributors. Such demands test the limits of complexity and logistical capacities of existing sorting technologies as well. Equipment needed to transport final groupings to downstream processes further increase as the quantity of sorting destinations increase. Transporting groupings from upstream to downstream locations in a continuous, sequential manner is not always possible, especially in larger systems. Moreover, the rates and timing of upstream processing are often poorly synchronized with downstream processes, necessitating buffer stations at various accumulation points throughout the distribution center. [0006] Accordingly, it is desirable to reduce the number of sorting destinations while maintaining high throughput. One method of reducing the number of sorting destinations is to introduce an intermediate or secondary sorting step. In conventional systems employing such methods, an intermediate sorting stage tends to decrease the number of sorting destinations in of the system. As an example, consider a distribution center for sorting various items into one thousand predetermined groups of items (“orders”). An intermediate sort could be implemented at a first sorting station to sort the items into 20 compound groups at 20 sorting destinations, with each compound group containing 50 orders. Each of the 20 compound groups could thereafter undergo an additional sorting step in which the compound groups are sorted into 50 order groups at 50 sorting destinations. This exemplary system could accomplish a thousand group sort with only 70 total sorting destinations (20+50=70). [0007] Prior attempts to introduce multiple sorting steps have revealed several drawbacks, especially if it is presumed that entropy must be reduced to the fullest practical extent at each shorting step. Consequently, these systems typically strive to maintain absolute discretion between the sorted groups or subgroups. That is, conventional systems do not allow intermixing between sorted groups. This requirement for absolute discretion places many restraints upon system configuration and flexibility, thereby decreasing system efficiencies. [0008] Further system limitations also tend to minimize the attractiveness of intermediate sort processing. Reductions in capital equipment realized from intermediate sorting tends to be at least partially offset by an increase in the hardware required to transport the goods between the sorting stations. Additionally, bottlenecking tends to occur at downstream sorting destinations when previously sorted groups are not transported away as fast as upstream processes are able to replenish their supply. In this regard, such systems tend to require added sorting destinations or large amounts of buffering or accumulation equipment to compensate for these timing problems. [0009] Accordingly, an improved system for sorting and distributing discrete items into large quantities of unique groups is desired. SUMMARY OF THE INVENTION [0010] The present invention addresses the shortcomings of the prior art by providing a convenient and cost-effective system and method for sorting large quantities of discrete items into a large number of groups for further routing and distribution. While the way in which the present invention provides these advantages will be described in greater detail below, in general, the present invention provides a system for efficiently sorting various items received from an upstream input source into various order groups for further downstream processing. The system may include intermediate sorting steps. Such intermediate sorting steps may be useful in reducing the overall number of sorting destinations required for the distribution system. The system may also include a non-discrete intermediate sorting step. In accordance with various embodiments of the present invention, such a non-discrete sorting step can increase the efficiency and reduce the overall size and complexity of distribution systems. [0011] In accordance with a further aspect of the present invention, a non-discrete sorting step is provided which sorts items into discrete groups, but which may also include regions of non-discrete items interposed between discrete groups. [0012] In accordance with a further aspect of the present invention, during the final sorting step, the discrete groups of items previously sorted in the intermediate sorting step may undergo a conventional final sort, whereupon the non-discrete items between the groups of discrete items may also undergo a final sort using additional final sort designations. BRIEF DESCRIPTION OF THE DRAWINGS [0013] A more complete understanding of the present invention may be derived by referring to the detailed description and claims, considered in connection with the figures, wherein like reference numbers refer to similar elements throughout the figures, and: [0014] [0014]FIG. 1 is a schematic block diagram of a conventional sorting/distribution system; [0015] [0015]FIG. 2 is a schematic block diagram of a discrete sorting stage; [0016] FIGS. 3 ( a - c ) are graphical, schematic illustrations of various embodiments of discrete sorting regions; [0017] [0017]FIG. 4 is a schematic block diagram of a secondary sort station; [0018] FIGS. 5 ( a - c ) are schematic block diagrams of various embodiments of secondary sort stations; [0019] [0019]FIG. 6 is a schematic block diagram of a first sorting station and a second sorting station; [0020] [0020]FIG. 7 is a schematic block diagram of a series of discrete sort regions, each separated by a non-discrete region; and [0021] [0021]FIG. 8 is a schematic block diagram illustrating various characteristics of discretely sorted groups. [0022] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention. DETAILED DESCRIPTION [0023] The present invention is described herein in terms of various functional components and processing steps. It should be appreciated that such functional components may be realized by any number of hardware or structural components configured to perform the specified functions. [0024] Conventional distribution systems typically require the sorting of thousands of items for ultimate packaging and shipping to various downstream customers and other recipients. Such distribution systems typically interact with a variety of input and output sources. FIG. 1 illustrates the process architecture typically found in common distribution systems 100 . Items are received by the distribution center through a variety of input sources 110 , such as shipping yards, delivery docks, mailrooms, and the like. The received items are processed in a distribution center 120 , typically in an intake processing location 122 . [0025] The processed items are then transported to a sorting station 124 . In its most basic sense, such sorting may involve individually selecting items from a large group of items to fulfill an individual order. For example, in the apparel industry, received items may be dumped in a central location, such as sorting tables. Employees then sort through the random piles of garments, for example men's and ladies' clothing, to select individual garments to fulfill a particular order. The selected items are then placed into individual bins to await further processing. [0026] After at least some of the items have been sorted into groups, the groups are typically transported to a shipping location 126 . Shipping locations typically process grouped items for shipment. Such processes include packaging the groups and placing the groups in appropriate containers for shipping, such as envelopes, bags, boxes, drums, containers, and the like. The processed groups are then transported 130 to a distribution center 140 for further sorting. The distribution center 140 typically sorts the groups according to shipper designation. For example, the sorted groups may be placed onto loading docks 150 for pick-up by U.S. mail, United Parcel Service, Federal Express, various trucking companies, and the like. [0027] As used herein, “group,” and various permutations thereof, typically relates to a plurality of items (or even constituting a logical group of items), such as an order for several items placed by a consumer from a catalog. “Sorting,” and various permutations thereof, means any activity in which an item is distinguished or selected from a non-homogeneous assemblage of items based on a given metric or characteristic, such as size, weight, color, geographic origin, hazardous/non-hazardous, perishable/non-perishable, and the like. [0028] As discussed above, conventional single stage sorting systems generally designate a single sorting destination for each group. In the example above, one hundred individual destination bins may be designated for one hundred different discrete order groups. However, as the number of required groups increases, the number of sorting destinations can quickly multiply to an unmanageable number. Prior attempts have been made to reduce the number of sorting destinations by introducing intermediate sorting steps, as discussed above. [0029] Referring now to FIG. 2, a schematic illustration of an intermediate sorting step used in a conventional sorting system 200 is shown. A primary induct 210 (e.g., a conveyer) is linked to a sorting station 222 . In the illustrated embodiment, sorting station 222 comprises a sorting conveyor 220 and an accumulator 230 , wherein accumulator 230 may include one or more sorting destinations 238 , 240 , and 242 . In the illustrated embodiment, the various sorting destinations may comprise structural bins, shutes, or partitioned regions; alternatively, the sorting destinations may simply comprise predetermined areas or regions on the surface of or otherwise within accumulator 230 . In this regard, it is not uncommon for such systems to comprise many sorting destinations, for example one hundred or more. [0030] Unsorted incoming items 212 are introduced into the sorting system 200 through primary induct 210 . The random items 212 may comprise virtually any number and configuration of items to be sorted, using virtually any sorting criteria. Moreover, the incoming items may be random, pseudo-random, unsorted, partially sorted, recycled items, or a mixture of recycled and newly introduced items. The incoming items may comprise any number of distinct items to be sorted into virtually any number of groups or compound groups. In the embodiment shown in FIG. 2, incoming items 212 are represented as three different classes of items (circles, triangles, and squares), such that the squares are assembled into destination 238 , the circles are assembled into destination 240 , and the triangles are assembled into destination 242 as conveyor 220 carries the items past the sorting destinations. [0031] As briefly mentioned above, each of the “classes” of items, for example, items represented as triangles, may constitute a compound group containing a number of subgroups to be sorted in a subsequent sorting operation. For example, as explained above, a first sorting station could sort the incoming items into 20 compound groups each containing 50 order groups. Each of the compound groups could then be subject to a secondary sort step where each of the 20 compound groups would be sorted into 50 individual order groups (not shown). This may be facilitated, for example, by manually or otherwise moving each of the sorting destinations (or sorting bins), or even accumulator 230 , to a downstream location for further sorting, such as another sorting station. [0032] Any suitable metric or set of metrics may be used to separate or group items in an intermediate sort. For example, items may be identified as having one or more characteristics, and thus be placed in a particular class corresponding to that characteristic or set of characteristics. Characteristics which differentiate one item from other items may include such things as the weight of the item, the size of the item, whether the item requires special handling such as refrigeration, or perhaps because the item is particularly fragile, or because it may constitute a biohazard or the like. Additional factors may include a time sensitivity associated with the items, or a particular geographic area to which the item is to be delivered, or even a particular currier scheduled to transport the item. [0033] With continued reference to FIG. 2, the items are sorted into groups which generally exhibit absolute discretion from other groups; that is, each group contains only items belonging to that group, and does not contain items associated with any of the other discrete groups. In practice, this generally involves some degree of physical separation 231 required between each of the sorted groups. This is typically accomplished by using one of several known techniques, generally involving ejecting incoming items from a conveyor in a first sorting station. In many installations, it may be convenient to sort groups of items onto a sorting table, accumulator, conveyor, or the like, or by ejecting the items in accordance with identifying characteristics into discrete chutes, bins, or the like, such that “like” items (as defined by predetermined characteristics) may be grouped together. [0034] In order to achieve a physical separation between discrete groups (or compound groups) of sorted items, it may be desirable to assemble items within a particular class unto one region at a sorting station, and to assemble a different class of items onto a separate, distinct region at the first sorting station, and so on, depending on the number of different groups of items to be sorted. In this context, each distinct region within which a class of items is assembled would correspond to a sorting destination. In order to ensure that a physical space exists between discrete groups, many systems employ the concept of a unique target region or target zone associated with each class of items, wherein the various target regions corresponding to the different classifications of items are mutually exclusive. [0035] In accordance with a further aspect of the present invention, the accumulator, sorting table, or other surface or structure wherein the intermediate sorting step is performed may also function as one or more of the following: (1) an accumulator for storing the intermediately sorted items until such time as they are reintroduced into the sorting process; (2) a transport mechanism for transporting the intermediately sorted items to a subsequent sorting or processing station; and (3) a conveyor or transfer mechanism for introducing the intermediately sorted items into a subsequent sorting or processing station. [0036] With continued reference to FIG. 2, the various sorting stations are typically separated by a physical space or “dead zone” 231 between each of the groupings to ensure absolute discretion among the intermediately sorted groups. However, these dead zones can result in certain inefficiencies, such as un-utilized accumulator or transport space, un-utilized conveyor space, or the like. [0037] With reference to FIG. 8, exemplary intermediate sort destinations 800 maybe schematically represented as a series of discretely sorted groups of items, including a first sort destination 810 , a second sort destination 820 , and a third sort destination 830 , with each sort destination characterized by a length L and separated from other sort destinations by a dead zone D. In the illustrated embodiment, destination 810 corresponds to an assembly of triangular items, destination 820 includes an assembly of circular items, and destination 830 includes an assembly of square items. Sort destination 820 is separated from destination 810 by a distance D1, and from destination 830 by a distance D2. Note that each sort destination includes a discretely sorted assembly of items sharing a similar characteristic or set of characteristics; that is to say sort destination 810 includes triangular items, but does not include circular items or square items; sort destinations 820 and 830 suitably exhibit similar homogeneity. [0038] With the output of the intermediate sort configured discretely as schematically shown in FIG. 8, the intermediately sorted items may then be processed in a subsequent sorting step. Referring now to FIG. 6, a sorting system 600 suitably comprises a primary induction conveyor 602 , an intermediate (or primary) sorting station 604 , and a final (or secondary) sorting station 606 . Intermediate sorting station 604 suitably comprises a conveyor 610 for conveying unsorted items through the sorting station, and an accumulator 631 wherein the intermediately sorted items are assembled. As stated above, the intermediate sorting station may sort any number of different classes of items into any convenient number of intermediately sorted groups or compound groups; for clarity, intermediate sorting station 604 is illustrated as intermediately sorting items into two groups onto conveyor 631 : a group of triangular items and a group of circular items. [0039] With continued reference to FIG. 6, the intermediately sorted items on accumulator 631 are transported to sorting station 606 , for example, by moving accumulator 631 , proximate sorting station 606 , by transferring the intermediately grouped items from accumulator 631 to an intermediary vehicle for transporting the intermediately grouped items to sorting station 606 , or by manually carrying the sorting destinations which include the intermediately sorted items from sorting station 604 to sorting station 606 . [0040] Sorting station 606 suitably comprises an input conveyor 640 (which may be the same as accumulator 631 , if desired), a sorting conveyor 650 (which may also comprise accumulator/conveyor 631 ), and one or more sort destinations. In the illustrated embodiment, sorting station 606 includes respective sorting destinations 620 and 622 , each of which are shown having three sorting destinations, but which may comprise virtually any desired number of destinations, as appropriate. Moreover, in the embodiment shown in FIG. 6, the sorting destinations are positioned on both sides of sorting conveyor 650 . It should be appreciated, however, that virtually any number of sorting destinations may be configured to interact with sorting conveyor 650 in any suitable manner. For example, the sorting destinations may extend along only one side of conveyor 650 , along both sides, or a plurality of separate sorting destinations may be spaced apart from one another and placed along either or both sides of conveyor 650 . Alternatively, sorting destinations may be positioned in various dimensions, such as above, below, circularly or semi-circularly circumscribing conveyor 650 , as appropriate. Indeed, although conveyor 650 is shown as a linear conveyor in FIG. 6 for convenience, it will be understood that conveyor 650 may assume any desired configuration, such as a rotating table, a series of conveyors which may extend from input convey 640 in a parallel or non-parallel fashion. [0041] With continued reference to FIG. 6, the discretely sorted groups introduced into sorting station 606 may be sorted into any number of desired groups. For example, when the compound group of intermediately sorted circles are processed at sorting station 606 as illustrated, one or more characteristics (or metrics) of these items may be identified and used to perform a higher resolution sort on these items. Depending on the number of characteristics used and the number of destinations employed at search station 606 , the circular items conveyed along conveyor 650 are assembled into one or both of sorting destinations 620 and 622 . The output of the items sorted in sorting station 606 may then be transported away, for example, through a transport (or “take away”) vehicle 608 which may be a wheeled cart, conveyor, accumulator, or the like. In accordance with one aspect of the present invention, transport vehicle 608 may perform one or more of the functions articulated above with respect to the accumulator/conveyor associated with the intermediate sorting station. [0042] If items within a particular group could be placed within the target zone with absolute certainty, i.e. if it could be assured that none of the items within a particular group extended outside the bounds of a target zone associated with that group's sort destination, then it would not be necessary to provide a space (or “dead zone”) between different groups of items in order to ensure that each group was absolutely discrete (i.e., that only items within the classification which defines a group were located within the target zone). However, absolute precision in projecting items into a target zone is extremely difficult and costly to achieve. [0043] Accordingly, presently known sorting technologies typically employ a physical separation between discrete groups to ensure that absolute discretion between groups is maintained. Moreover, since a physical range of uncertainty or deviation from a target zone is generally experienced, presently known systems employ a target zone as well as an expanded target zone, the latter including a range of deviation from the absolute target zone to accommodate those items which are not placed entirely within the absolute target zone. By maintaining a physical separation even between expanded target zones for adjacent groups, presently known systems are able to maintain absolute discretion between sequential groups while also accommodating for the uncertainty (and hence deviation) associated with the error in assembling items into an absolute target zone. One drawback associated with this approach, however, relates to the creation of so called “dead zones” which have heretofore been thought of as necessary to ensure the complete isolation (i.e., absolute discretion) of one group with respect to a nearby group of items. [0044] For example, when an intermediate sorting step is employed to sort items into discrete groups on a conveyor, a dead zone may result in down time at a subsequent sorting station (i.e., no sorting is accomplished during conveyance of the dead zone through the sorting station), in addition to the inherent inefficiencies associated with unoccupied regions of a moving conveyor. [0045] Referring again to FIG. 8, in accordance with a preferred embodiment of the present invention, zones D 1 and D 2 which, in prior art systems typically comprise dead zones where no items are present, may be exploited to achieve enhanced efficiencies by permitting some items from the adjacent target zones to be assembled into the “spaces” between discrete groups. For example, the target zone for group 810 is indicated by L 1 . However, the present inventor has recognized that a sorting device which projects or otherwise assembles items into a group typically does so with a known degree of uncertainty. Hence, if the maximum uncertainty from target zone L 1 were expressed as D 1 , and if the maximum deviation (or uncertainty) from target zone L 2 were less than or equal to length D 1 , then it may be desirable to allow an intermediate non-discrete zone 814 to exist between respective discrete zones 810 and 820 , as well as for the non-discrete zone D 2 between respective groups 820 and 830 and so on. [0046] Thus, in accordance with this aspect of the invention, as long as absolute discretion within the actual target zones L 1 and L 2 is maintained, the presence of a non-discrete region of known dimensions between zones of absolute discretion can significantly enhance the overall efficiency of the sorting system, without compromising subsequent sorting, for example the discrete final sorting of items. Stated another way, during the intermediate sorting step depicted in FIG. 8, it is acceptable to allow a reasonable degree of entropy or randomness to exist in the intermediate non-discrete zones because this does not compromise the absolute discretion within the absolutely discrete zones. In this way, rather than having a dead zone between absolutely discrete regions wherein the sorting process is suspended, these “dead zones” may be exploited in the present invention as non-discrete zones to permit continuous sorting of non-discrete zones interspersed between the sorting of discrete zones. [0047] More particularly, in referring now to FIG. 3, target zones for assembling discrete groups of items at a sorting station are illustrated schematically. In FIG. 3A, a sorting platform (e.g. conveyor) 302 illustrates the known technique of assembling separate groups and maintaining absolutely discretion within the group through the use of dead zones between discrete groups. FIG. 3 illustrates one embodiment of the present invention wherein regions of non-discrete items are interposed between regions of discrete items utilizing approximately the same amount of sorting area (for example, the same length of conveyor belt as shown in FIG. 3A). [0048] [0048]FIG. 3C sets forth an alternate embodiment of the present invention wherein non-discrete groups are interposed between discrete groups using a smaller area of total sorting capacity. [0049] In the example shown in FIG. 3A, four groups of discrete items are intermediately sorted with dead zones between each discrete group to ensure absolute discretion within each group. An accumulator 326 , which may be a conveyor belt, sorting table, or the like, comprises a first sorting area 308 for assembling a first class (see 1 ) of items, a second sorting area 310 for assembling a second class (C 2 ) of items, a third sorting area 312 for assembling a third class (C 3 ) of items, and a fourth sorting area 314 for assembling a fourth class (C 4 ) of items. As discussed in greater detail below, sorting areas 308 - 314 may be referred to as sorting destinations D 1 -D 4 , respectively. Thus, sorting station 326 may be said to include four separate sorting destinations for assembling four discrete groups of items C 1 -C 4 [0050] With continued reference to FIG. 3A, the target zone within which the sorting station is capable of assembling the items into area 308 is graphically depicted by a probability curve 303 . More particularly, the absolute target zone within which items may be assembled (e.g., projected, ejected, dropped, or the like) is bound by the area under curve 303 between points 318 and 320 . The error, or uncertainty, associated with a sorting station's ability to accurately assemble items into a target area is represented by a first error region 322 (shown to the left of point 318 ) and a second deviation area 324 (shown to the right of point 320 ). Thus, the entire area under probability curve 303 may be thought of as the expanded target zone and includes the absolute target zone between points 318 and 320 , as well as the uncertainty target zones 322 and 324 . [0051] By determining the expanded target regions for the items to be sorted within a sorting station, and by placing appropriating dead zones 326 between the expanded target regions, absolute discretion among intermediately sorted groups may be maintained as shown in FIG. 3A. In this regard, it is instructive to define the target areas in terms of a unit of measure, schematically illustrated as unit 380 , which may be expressed in terms of inches, feet, meters, or the like depending on the items to be sorted. In the embodiment shown in FIG. 3A, each of the absolute target zones are two units long, and include one unit of deviation on each side, so that the expanded target zones for each of the sorting destinations shown in FIG. 3A are four units in length. The respective dead zones 326 interposed between the sorting destinations are two units in length, although those skilled in the art will appreciate that any desired lengths or areas may be employed depending on the sorting objectives at that particular sorting station. [0052] Referring now to FIG. 3B, a first embodiment of the present invention includes an accumulator (e.g. conveyor) 304 comprising a first area 328 for assembling items C 1 , a secondary of 330 for assembling items C 2 , a third area 332 for assembling items C 3 , and a fourth area 334 for assembling items C 4 . Thus, the accumulator shown in FIG. 3B may also be thought of as including four sorting destinations D 1 -D 4 associated with four discrete groups. In contrast to the dead zone technique of maintaining absolute discretions set forth in FIG. A, the embodiment shown in FIG. 3B exploits this dead zone to allow the assembly of non-discrete items into the spaces between the absolute sorting destinations 328 - 334 . More particularly, a non-discrete regions 348 interposed between discrete regions 328 and 330 allows for some of the C 1 items and some of the C 2 to be assembled into the non-discrete region. [0053] Similarly, the embodiment shown in FIG. 3B allows for some of the C 2 items and some of the C 3 items to be assembled into a non-discrete region 350 interposed between discrete region 330 and discrete region 332 , and so on with respect to non-discrete region 352 . [0054] The probability (or certainty) with which the sorting station is capable of assembling items C 1 into area 328 is expressed as a probability curve 305 . In particular, the area under curve 305 between points 338 and 340 represents the absolute target zone within which items C 1 may be assembled into area 328 . [0055] An expanded target zone indicated by error regions 342 (to the left of absolute target region 336 ) and error zone 344 (to the right of absolute target region 336 ) represents the total length of conveyor 346 within which items C, may be assembled. Similarly, the degree of certainty with which the sorting station assembles items C 2 into area 330 may be expressed by an analogous probability curve, and so on with respect to areas 332 and 334 . As a result, although items C 1 and C 2 may be assembled into non-discrete region 348 , and items C 2 and C 3 may be assembled into non-discrete region 350 , absolute discretion among the various sorted groups is nonetheless maintained inasmuch as area 328 contains only items C 1 , area 330 contains only items C 2 , and so on. In this way, absolute discretion is maintained within sorting destinations D 1 -D 4 , while exploiting the physical space between discrete sorting destinations. [0056] Moreover, the embodiment shown in FIG. 3B provides for discrete sortation of four groups of items without requiring additional accumulator space. In accordance with a further aspect of this embodiment, the absolute target zones may be increased from two to four units, and the total target zone may be increased from four to eight units as compared to the embodiment shown in FIG. 3A, without consuming additional accumulator area. As described in greater detail below in connection with FIG. 5, the advantages associated with the embodiment shown in FIG. 3B may be achieved while still maintaining absolute discretion among sorted groups in a subsequent sorting process. [0057] With momentary reference to FIG. 3C, an alternate embodiment of the present invention provides an accumulator 306 having sorting areas 354 , 356 , 358 and 360 for discretely sorting items C 1 -C 4 in much the same way as discussed above in connection with FIG. 3B. In the embodiment shown in FIG. 3C, however, a probability curve 307 comprises an absolute target zone of two units of length between points 364 and 366 , having respective error regions 368 and 370 on either side of the absolute target zone, with the error regents being one unit of length. In this way, the expanded target zones for each of the groups is the same as shown in FIG. 3A. By providing respective non-discrete regions 374 , 376 , and 378 between the discrete regions, and further by ensuring that the area of each non-discrete region is sufficient to accommodate the uncertainty zones associated with the nearby discrete regions, absolute discretion is maintained within each of sorting destinations D 1 -D 4 , while at the same time eliminating dead zones. In accordance with one aspect of the embodiment shown in FIG. 3C, four discrete groupings are obtained while using substantially less accumulator area, resulting in significant savings in capital equipment. [0058] Those skilled in the art will appreciate that various factors may be considered when designing intermediate sorting processes having non-discrete regions in accordance with the present invention, including conveyor speed, the coefficients of friction between items and the surface of the conveyor, the size, weight, and number of items to be sorted, and the like. Furthermore, in accordance with the present invention, various tradeoffs may be made between capital equipment cost, speed, and other factors allowing customization and optimization of various sorting processes through the use of intermediate short steps which include non-discrete regents. [0059] Referring now to FIG. 5, various final sorting processes will now be discussed. In this regard, the present inventor recognizes that incorporating non-discrete regions in an intermediate sorting process requires that the existence of these non-discrete regions be accommodated in a subsequent (e.g. final) sorting process. [0060] The principals enunciated herein may be extended to virtually any number of classifications of items in the context of a sorting system involving a discrete final sort and one or more intermediary non-discrete sorting steps. [0061] In a single stage sorting environment, a single destination is typically used for each discrete group that the incoming items are sorted into. Thus, in a single stage process, the number of sorting destinations (d) is equal to the number of sorted groups (S). For a conventional two stage discrete sorting process, the number of discrete groups may be expressed as S 1 ×S 2 where S 1 is the number of sorts in the first or primary sorting step, and S 2 is the number of sorts performed in the secondary sorting process. For this type of discrete sortation, the number of sorting destinations may be expressed as d=S 1 +S 2 . These relationships can be extrapolated to virtually any number of discrete sorting steps, such that the total number of sorted groups is equal to the product of the respective number of groups sorted at each of the stages (S 1 ×S 2 . . . ×S n ), and wherein the number of sorting destinations is equal to the sum of the respective sort points at each stage (S 1 +S 2 . . . +S n ). [0062] In accordance with one aspect the present invention, the tradeoff for relaxing the requirement of absolute discretion among sorted groups at an intermediate sorting stage involves an increase in the total number of sort destinations compared to the total number of sort destinations that would be required for the same number of total groups in a fully discrete multi-stage sorting process. [0063] Thus, in the context of the present invention, for a two stage sort the total number of discrete groups may be expressed as S 1 ×S 2 , where again S 1 is the number of sort points at the primary sorting stage and S 2 is the total number of sort points in the secondary sorting stage. In this context, the primary sorting stage is the intermediate, non-discrete sorting process discussed above, and the secondary sorting stage is the subsequent or, in the case of a two stage sortation process, the final sorting stage. However, in contrast to prior art sortation processes in which each stage maintains discretion between each sorted group, the number of sorting destinations required in the present invention may be expressed as S 1 +S 2 +D 2 , where S 1 is the number of sorting points in the primary stage, S 2 is the number of sort destinations in the secondary stage, and D 2 is the number of S 2 groups from a discrete zone which can overlap with S 2 groups of an adjacent discrete zone in the uncertainty zones in the non-discrete sort. [0064] The present invention thus provides one or more intermediate sorting steps in a two stage or multi-stage sort which allows greater flexibility in defining target zones and non-discrete zones during an intermediate sorting step, and which may be implemented using a secondary sorting stage with fewer total sorting destinations then would be required to sort the same number of groups in a conventional single stage sort. Although the number of discrete sorting destinations employed in the present invention will generally be greater than the number of destinations required to sort the same number of groups in a conventional multi-stage discrete sorting paradigm, in many applications the benefits of greater flexibility in defining the target zone far outweigh the incremental cost of additional sorting destinations. [0065] Referring now to FIG. 5, the manner in which the output intermediate non-discrete sorting stage is accommodated in a subsequent sorting stage in the context of the present invention will now be described. [0066] [0066]FIG. 5( a ) is a schematic diagram of a secondary sortation process which follows a previous (intermediate), non-discrete sorting process in accordance with the present invention. More particularly, a secondary sorting station 502 comprises a conveyor 504 configured to introduce intermediately sorted items into the secondary sorting process. Conveyor 504 comprises respective discrete regions 506 , 508 , 510 , and respective non-discrete regions 512 and 514 . [0067] As discussed in greater detail below in connection with FIGS. 5 ( b ) and 5 ( c ), the intermediate non-discrete sorting process may be implemented in virtually any number of sorting stages in accordance with the present invention; for simplicity, the simple case of S 2 =1 will first be described in the context of FIG. 5( a ). That is, sorting stage 502 is a single point sorting stage, which is configured to place discretely sorted items into takeaway bins, and is not intended to further sort discretely sorted groups into smaller groups. [0068] If the items grouped on conveyor 504 were discretely sorted as discussed above in connection with FIG. 3( a ), regions 506 - 510 would comprise discretely sorted items, and regions 512 and 514 would simply comprise dead zones. In such a case, only a single sorting destination, for example destination 516 , would be required, to the extent the sort destination could “clear” its load during the dead zones, for example by opening Bombay doors, replacing a full bin with an empty bin, or the like. [0069] With continued reference to FIG. 5( a ) and in accordance with the present invention, a first class of items (C 1 ) are discretely assembled in area 510 , a second group of items (C 2 ) are discretely assembled within area 508 , and a third group of items (C 3 ) are discretely assembled onto area 506 . Depending on the number of sort points associated with the prior non-discrete sortation process, conveyor 504 may contain virtually any number of discretely grouped items. [0070] In the embodiment illustrated in FIG. 5( a ) wherein S 2 =1, when area 510 is sorted, the discretely sorted items C 1 are sorted into sorting destination 516 . When sorting stage 502 has finished processing area 510 , non-discrete region 514 is then processed, such that the goods in Class C 1 are placed into sorting destination 516 , and the items corresponding to Class C 2 are placed into sorting destination 518 . Thereafter, items corresponding to Class C 2 are transferred from area 508 into sorting destination 518 , during which time sorting destination 516 can clear its load. Thus, for the case where S 2 =1, the total number of sorting destinations required for sortation stage 502 may be expressed as S 2 +D 2 , where D 2 corresponds to the maximum number of items from a discrete zone which may be assembled into its adjacent non-discrete zone. In the context of FIG. 5( a ), since each discrete zone includes only one class of items, D 2 is equal to 1, so that a total of two sorting destinations are needed for the embodiment shown in FIG. 5( a ). [0071] Referring now to FIG. 5( b ), a secondary sorting station 520 is illustrated for the case where S 2 =2; that is, each discretely sorted group which is introduced into the secondary sorting stage is sorted into two groups. [0072] Sorting station 520 of FIG. 5( b ) comprises discretely sorted zones 522 , 524 , and 526 , interposed with non-discrete zones 528 and 530 . Discrete zone 526 includes only items corresponding to Class 1 and Class 2 , discrete zone 524 includes only items in Class 3 and Class 4 , and discrete zone 522 includes only items in Class 5 and Class 6 , and so on. As discussed above, some of the items from Class 1 and Class 2 may also spill over into non-discrete region 530 . Similarly, some of the items from Class 3 and Class 4 may spill over from discrete zone 524 into non-discrete zone 530 . Thus, it is possible that four different classes of items may be assembled into non-discrete region 530 . [0073] Similarly, non-discrete region 528 may include some items from Class 3 and Class 4 , as well as some items from Class 5 and Class 6 which may have spilled over from discrete region 522 . During processing of discrete region 526 , items from Class 1 and Class 2 are assembled into sorting destinations 532 and 534 , respectively. However, because the non-discrete regions in FIG. 5( b ) may include up to four classes of items (two classes from each of the adjacent discrete regions), additional sorting destinations 536 and 538 are needed to accommodate sorting of the non-discrete regions. The maximum number of groups which may be assembled into a non-discrete region from an adjacent discrete region in the embodiment shown in FIG. 5( b ) is two. Hence, the total number of sorting destinations for the embodiment figure shown in FIG. 5( b ) may be expressed as S 2 +D 2 =2+2 =4. [0074] With reference to FIG. 5( c ), the secondary sorting stations which may be used in the context of the present invention following an intermediate non-discrete sorting stage may be extrapolated to virtually any number of sorting points as subscript 2 as are desired in the secondary sorting stage. [0075] More particularly, secondary sort stage 540 suitable comprises S 1 (the number of sort points in the previous sorting stage) discrete regions, for example regions 542 , 544 , and 546 . Non-discrete regions such as regions 548 and 550 may be interposed between discrete regions, as desired. As discussed above in connection with the prior art discrete sortation process shown in FIG. 3( a ), the total number of sort destinations needed in the embodiment shown in FIG. 5( c ) would be equal to n if the discrete regions were separated by dead zones. However, in accordance with the present invention wherein non-discrete regions are interposed between the discrete regions, a maximum of 2n sorting destinations would be needed to ensure discrete sorting at the output of stage 540 . That is, since the maximum number of items which may spill over from a discrete zone into an adjacent non-discrete zone corresponds to S 2 =n, then a total number of destinations for the secondary sort may be expressed as S 2 +D 2 =n+n=2n. [0076] Depending on the particular items being sorted, it may be possible to enjoy even further efficiencies in accordance with various other aspects of the present invention. For example, in order to reduce the number of total sorting destinations in the secondary sorting stage, it may be desirable to perform a discrete sort of the discrete regions, and to process the items in the non-discrete zones as dictated by the particular application. For example, items in the non-discrete zone may be low cost commodities such as dirt, sand, water, or the like, which could simply be discarded. Alternatively, items in the non-discrete region could be recycled through the sortation process, for example by reintroducing the non-discrete items into the non-discrete sorting process. In accordance with yet a further aspect of the present invention, if it can be determined that certain classes of items have a high probability of appearing in a non-discrete zone, and other classes of items have a very low probability of appearing in the non-discrete zone, it may only be necessary to provide final sorting destinations for those items likely to appear in the non-discrete zones. [0077] If it desired to discretely sort all of the items in the non-discrete regions during the secondary sortation process, the total number of sorting destinations required in accordance with the present invention exceeds the number of sorting destinations which would be required to sort the same number of groups using only discrete intermediate sortation. However, the total number of sorting destinations needed in the present invention is still far less than the total number of sorting destinations needed to sort the same number of groups using a single stage process. Moreover, in many applications the efficiencies enjoyed from relaxing the target zones in the intermediate sort far outweigh the incremental increase in file sort destinations needed at the secondary sort. [0078] For example, although the number of sort points in the first and second stages of a two stage process is largely a matter of design choice in view of the particular application, a comparison of total number of sort destinations is in the present invention vis-a-vis prior art techniques may be simplified by presuming that the first and second sort stages have the same number of sort points. That is, S 1 =S 2 =S. The following chart compares the total number of sorting destinations needed to discretely sort a given number of total Groups to be sorted. In a discrete two stage process, the total number of sorting destinations d=G=S 1 +S 2 =2s. For the non-discrete intermediation step described herein, the maximum number of total sort destinations for a two stage process may be expressed as d=S 1 +2 S 2 =3s. Finally, sorting the same number of Groups using a single stage process would require a total number of sorting destinations d=G=S 2 . TABLE 1 G Discrete Non-discrete (# of Intermediate Intermediate groups) S Sort Sort Single Stage 4 2 4 6 4 9 3 6 9 9 25 5 10 15 25 100 10 20 30 100 400 20 40 60 400 2,500 50 100 150 2,500 [0079] In accordance with various aspects and embodiments of the present invention, this above-described system relaxes the notion that minimum entropy (maximum order) is required at each discrete stage of the system. As described herein, the relaxing of the target zone and the use of non-discrete regions result in numerous efficiencies for the sorting system thereby offering remarkable improvements in overall operational costs. [0080] While the present invention is set forth herein in the context of the appended drawing figures, it should be appreciated that the invention is not limited to the specific form shown. For example, several figures demonstrate a two-stage sorting process comprising a primary and secondary stage sort. As practitioners in the art will appreciate, much greater levels of complexity may be employed in accordance with the present invention. For example, a sorting system may be comprised of a dozen or more intermediate sorting stations. Further, several drawings demonstrate a simplistic sorting process comprised of two or three groups of items. However, those skilled in the art will appreciate that the present invention has application in much more complex sorting and distribution systems, comprising quaternary and various other higher-level order sorting metrics. [0081] Additionally, practitioners will also appreciate that intermediate sorting processes may also occur at the various induction points or upon transfer to various sort stations.
A system and method for distributing and sorting discrete items into a large quantity of discrete groups is provided. The system includes multiple sorting steps including an upstream sorting step that sorts items into both discrete and non-discrete groups and a downstream sorting step that sorts the non-discrete groups into discrete groups for further processing.
8
[0001] This is a continuation-in-part application claiming priority to U.S. patent application Ser. No. 10/642,913, entitled “Polymer Composition and Method of Rapid Preparation In Situ” filed on Aug. 18, 2003, which is a continuation application claiming priority to U.S. patent application Ser. No. 09/946,996, entitled “Polymer Composition and Method of Rapid Preparation In Situ” filed on Sep. 5, 2001, the entire contents of both being hereby incorporated by reference. BACKGROUND [0002] The present invention relates to a polymer composition and an in situ method of producing a polyurea to create an almost instantaneous, nonreversible, predictable, adjustable, and substantial viscosity increase in a thermosetting polymeric resin admixture. [0003] Conventional methods of making particle filled thermosetting resin molded parts typically experience difficulties with particles either sinking or floating in the resin admixture used to mold the desired parts. The tendency for particulate fillers to sink or float in the resin admixture used to mold such parts has the effect of destroying the homogeneity of the resin admixture, thereby causing unwanted density gradients in the final molded parts. [0004] Previously, those skilled in the art used thixotropic agents such as fumed silica or certain clays to build viscosity in the resin admixture and keep the particulate fillers suspended. However, these agents were of limited utility because the amount of viscosity build was limited, and because special high shear mixing equipment was required to shear the thixotropic agents into the resin prior to addition of the fillers. This high shear mixing equipment has a tendency to damage fragile, hollow, spherical glass bubble fillers, making them useless. Further problems occur due to the fact that the resin admixtures have to be kept constantly sheared to prevent the mix viscosity from starting to build before the resin admixture is transferred to the mold. Frequently, air entrapment or filler migration occurs because the thixotropic agent is not completely effective. Conventional thixotropic agents simply build viscosity without “freezing” the filler particles in place. [0005] In some thermosetting resins, particularly polyurethanes and epoxies, said thermosetting resins get very hot, and actually undergo a substantial heat induced viscosity decrease before they gel. This heat induced viscosity decrease, prior to the gellation of the resin admixture, tends to exacerbate the tendency of the light or heavy filler particles to sink or float, thereby decreasing the ability of the molder to make molded parts without density gradients. SUMMARY [0006] The present invention pertains to a polymer composition prepared from a thermosetting polymeric resin admixture having a subcomponent gelled phase or polyurea. The gelled phase or polyurea is capable of trapping particles of widely differing particle densities within the resin admixture, thereby preventing these particles from either sinking or floating. Subsequent to this rapid viscosity increase, the resin admixture can be cured in the normal fashion, yielding a useful filled polymer molded part. Because a very rapid and substantial viscosity build is accomplished in said resin admixture, and particles of widely varying densities are trapped in place, their movement through the resin admixture is prevented, resulting in the homogeneity of the resin admixture density being preserved, without any appreciable density gradients being formed in the resin admixture, or the resulting molded part. The gelled polyurea of the resin admixture is generated in situ and is evenly distributed throughout the resin admixture. [0007] In contrast to conventional methods which rely upon thixotropic agents, the user of the current resin admixture can change the amounts and types of reactants used to cause the thickening to occur, giving the user precise control over the time and degree of viscosity build that occurs. This control over the timing and degree of viscosity build that occurs in the resin admixture is unavailable to a user of conventional thixotropic agents. [0008] The rapid, suddenly-induced increase in viscosity of the resin admixture can be timed to occur in the mold, after it is filled, to fix the low or high density particles in place without density gradients. Thus, the resin admixture can first be mixed, de-aerated, and pumped or poured easily into the mold while still in a low viscosity state and without trapping excessive air bubbles. This eliminates the need for high shear mixing equipment and other equipment viscosity limitations. Once the resin admixture has been transferred to the mold, and the density has been fixed without density gradients, the resin admixture can be gelled and cured in the usual manner to produce the finished polymer composition. [0009] The thermosetting resin admixture can utilize a combination of several reactive polymers, including but not limited to polyurethanes, epoxies, and unsaturated polyesters, and a combination of both low and high density fillers, either mineral or synthetic. The gelled polyurea phase within the resin admixture has the ability to trap, and hold in suspension, particulate matter or fillers of widely varying densities and in a wide range of amounts. The particulate matter may have a substantially higher, higher, lower, or substantially lower density than the density of the resin admixture, or may have a mixture of densities. [0010] The ungelled phase of the resin admixture is composed of various thermosetting resins which can be solidified into a rigid resinous mass for the purpose of casting a wide variety of useful objects, these objects containing evenly distributed particulate matter, or blends of particulate matter, which impart desirable characteristics to the molded part. The desirable characteristics may include weight gain, weight reduction, increased or decreased abrasion resistance and wear properties, increased strength or toughness, improved impact resistance, increased or decreased coefficient of friction, increased or decreased coefficient of restitution, increased or decreased oil absorption properties, increased or decreased dielectric properties, or combinations of these properties. [0011] The polymer composition is particularly useful in the production of bowling balls, although it is may be used in any molded polymer parts. The gelled polyurea phase maintains the uniformity of fillers and additives incorporated during the preparation of the molded polymer part. The fixation of the particulate matter within the gelled phase allows for the dramatic slowing of the gel and cure rate of the resin polymer used in the resin admixture, which subsequently results in a finished molded part which is much less likely to have defects such as burns and cracks. The burning and cracking are generally caused by an over-accelerated gel and cure rate. Surface quality is also improved, due to the reduced porosity caused by air entrapment. [0012] Without wanting to be bound by theory, the technology behind the polymer composition in the thermosetting resin admixture is predicated on the relative kinetics of competing chemical reactions, and the excess amount of certain of those chemicals to limit molecular weight development of some products while at the same time providing a chemical supply for subsequent secondary reactions. Reactive components must be separated in different vessels prior to mixing, which initiates the chemical reactions. Inert fillers are maintained uniformly dispersed within the fluids of the individual vessels by continuous mixing or recirculation techniques commonly used and commercially available to those in the art. BRIEF DESCRIPTION OF DRAWINGS [0013] FIG. 1 shows a general view of a method and apparatus for preparing the polymer composition. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0014] The present invention relates to a polymer composition in a thermosetting resin admixture which includes as a subcomponent a gelled or polyurea phase. The in situ generation of the polyurea phase produces a substantial and controllable viscosity increase that enables the trapping and fixation of particulate matter within the resin admixture, eliminating density gradients. The resin admixture is useful for the production of any molded parts containing particulate matter, and particularly for the production of bowling balls. [0015] Although other very rapidly gelling polymers could be used, the gelled phase within the resin admixture preferably comprises a polyurea. Polyurea (RNHCONHR) is a product of the reaction between an isocyanate (OCN—R) and a companion reactant such as an amine (RNH 2 ), carboxylic acid (RCOOH), or water (H 2 O). In the presence of an excess amount of either isocyanate or companion reactant, the polyurea formed is of low molecular weight and is essentially a dimer. In the presence of approximately equal or non-limiting amounts of either isocyanate or companion reactant, the polyurea formed will be of higher molecular weight and will impart higher viscosity to the mixture. In preferred embodiments, the polyurea has a low number average molecular weight, from about 200 g/mole to about 2000 g/mole, and more preferably from about 200 g/mole to about 300 g/mole. Unless otherwise stated, molecular weight means number average molecular weight. [0016] The polyurea gelled phase is produced in situ when all of the components for the resin admixture are mixed together. In a preferred embodiment, the polymer composition is prepared by mixing compounds comprising a polymer resin material, an isocyanate, a companion reactant, a filler material, and a plasticizer or diluent material. Only the isocyanate and the companion reactant react to form the polyurea. [0017] Once the components are mixed, a primary and a secondary reaction occur. In the primary reaction, the polyurea is generally formed within 1 to 30 seconds. This allows the polyurea to be formed at the time of the molding, or just after the mold is filled. At this point, the polyurea is in a gelled phase but is still capable of being incorporated into the backbone of the polymer matrix. In the secondary reaction, polymerization occurs within the thermosetting resin admixture. With the appropriate selection of reactants and properties, the gelled polyurea holds the particulate filler mix in suspension while the secondary reaction proceeds. Upon completion of the secondary reaction, the gelled polyurea and any particulate filler contained therein are evenly dispersed throughout the cured polymer. [0018] The primary reaction between the isocyanate and the companion reactant forming the polyurea is much faster (from 100 to 1000 times faster) than other competing reactions which could take place with the isocyanate, such as reactions with a primary alcohol (ROH). The polyurea-forming reaction is also much faster than other reactions with an amine, such as reactions with an epoxide. Thus, there is no reasonable likelihood that the secondary reaction or any competitive reaction will consume one of the essential reactants needed to produce the polyurea. Furthermore, there is no reaction between an isocyanate and an epoxide, or between an amine and a hydroxyl containing compounds, which allows for convenient separation of the reactants until polymerization and polyurea formation is desired. The formation of polyurea is accomplished in situ, which allows formation of the polyurea at the time of application or molding. After gellation, the polyurea is available to be incorporated into the backbone of the polymer matrix. [0019] The polymer composition making up the resin admixture is preferably prepared by mixing compounds comprising, based on volume, from about 40 to about 68 percent of a polymer resin material, from about 0.1 to about 5 percent of an isocyanate, from about 2 to about 15 percent of a companion reactant such as an amine, from about 0.1 to about 13 percent of a filler material, and optionally from about 20 to about 35 percent of a plasticizer material and from about 0 to about 20 percent of a diluent material. A preferred embodiment utilizes a ratio of isocyanate to amine ranging from about 1:10 to about 1:40 based on volume. [0020] Preferably, the components of the resin admixture are held separately in different vessels until the time that mixing and reaction is desired. In a preferred embodiment, a first vessel will contain a polymer resin material and an isocyanate. A second vessel may then contain an amine and a plasticizer or diluent material. A filler material may be present in either vessel. When the contents of the vessels are mixed, a polyurea of low molecular weight is formed immediately as a result of the primary reaction. The polyurea gel matrix then holds the filler in suspension during the interval required for the secondary reaction of the polymer resin to proceed to completion. The resulting polymer composition that is formed preferably contains by volume from about 1 to about 3 percent polyurea, from about 55 to about 75 percent cured epoxy polymer, from about 0.2 to about 30 percent particulate filler, and from about 0 to about 40 percent inert plasticizer or diluent material. These volume amounts may vary depending on the desired properties of the final polymer. The resulting polymer composition can be analyzed using a combination of techniques such as FTIR Spectroscopy, NMR Spectroscopy, HPLC, Mass Spectrometry and other analytical techniques commonly used in plastics characterization. [0021] The polymer resin material may be a mixture of one or more epoxies, unsaturated polyesters, polyurethanes, or various other thermosetting plastics. Epoxies are monomers or pre-polymers that further react with curing agents to yield high performance thermosetting plastics. Epoxy resins are characterized by the presence of a three membered cyclic ether group. Unsaturated polyesters are macromolecules with polyester backbones derived from the interaction of unsaturated dicarboxylic or polycarboxylic acids or anhydrides and polyhydric alcohols. Polyurethanes contain urethane groups in their backbone. They are obtained by the reaction of a diisocyanate or polyisocyanate with a macroglycol (polyol), or with a combination of a polyol and a short chain glycol extender. [0022] In a preferred embodiment, the polymer resin material is an epoxy resin material. Preferably, the epoxy resin material comprises a bisphenol-A epoxy resin. A bisphenol-A epoxy resin is the reaction product of epichlorohydrin and bisphenol-A. Examples of a bisphenol-A epoxy resin include Dow DER-331 (Dow Chemicals, Midland, Mich.), Shell Epon-828 (Shell Chemical Corporation, Houston, Tex.), and Shell Epon-826 (Shell Chemical Corporation). The epoxy resin is preferably an aromatic epoxy that causes tight cross-linking. In preferred embodiments of the resin admixture, the epoxy resin ranges from about 40 to about 68 weight percent of the resin admixture, preferably from about 44 to about 62 weight percent of the resin admixture, and most preferably from about 48 to about 58 weight percent of the resin admixture. [0023] The isocyanate is preferably of low molecular weight and viscosity. An equivalent weight of from about 100 g/mole to about 140 g/mole is preferred. The viscosity of the isocyanate should preferably be below 200 cps at 25° C. Preferred examples of the isocyanate include aromatic poly (MDI) isocyanates, such as polymethylene polyphenylisocyanate, and aliphatic isocyanates, such as hexamethylene diisocyanate. Other preferred examples include 4,4-diphenylmethane diisocyanate, such as BASF M-20 MDI, a polymeric MDI (BASF Corporation, Wyandotte, Mich.). In preferred embodiments of the resin admixture, the diisocyanate ranges from about 0.1 to about 5 weight percent of the resin admixture, preferably from about 0.5 to about 3 weight percent of the resin admixture, and most preferably from about 1.5 to about 2 weight percent of the resin admixture. [0024] The companion reactant which reacts with the isocyanate to form the polyurea is preferably an amine. The amine is preferably an aliphatic amine, such as n-aminoethylpiperazine (“AEP”), diethylenetriamine (“DETA”), or triethylenetriamine (“TETA”). Other preferred amines include tris (dimethyl amino-methyl phenol), tetraethylene pentamine (“TEPA”), and ethylenediamine. In preferred embodiments of the resin admixture, the amine ranges from about 2 to about 15 weight percent of the resin admixture, preferably from about 4 to about 10 weight percent of the resin admixture, and most preferably from about 5 to about 7 weight percent of the resin admixture. Other suitable companion reactants include carboxylic acids, such as carboxylic acid terminated polyesters, and water. [0025] In further preferred embodiments, when used in combination with an epoxy resin having an equivalent weight of approximately 190, the amines can be used in the following amounts: AEP having an equivalent weight of about 43, at about 22.7 parts per hundred; DETA having an equivalent weight of about 20.7, at about 10.9 parts per hundred; TETA having an equivalent weight of about 24.5, at about 12.9 parts per hundred; tris (dimethyl amino-methyl phenol) at about 10 parts per hundred; TEPA having an equivalent weight of about 27, at about 14.2 parts per hundred; and ethylenediamine having an equivalent weight of about 60, at about 31.6 parts per hundred. Any combination of these amines may be used to cure an epoxy resin having an equivalent weight of approximately 190, so long as the equivalent weights of the amines add up to the amount needed to react with the resin. Thus, various blends of the listed amines can be used to develop the cure cycle and physical properties that are desired in the finished polymer. [0026] A preferred embodiment of the modified epoxy resin may also contain a filler material. The filler material can have a density ranging from about 0.009 g/ml, such as a thermoplastic microballoon, to about 11.3 g/ml, such as lead powder, and may comprise from about 0.2 percent to about 30 percent by volume of the total polymer composition. Preferred examples of the filler material include solid glass spheres, such as Potters 300A (otters Industries, Valley Forge, Pa.), hollow glass spheres, such as Potters 110P8, Potters Q-300, Potters 6014, or Potters 6048 (Potters Industries), hollow thermoplastic spheres, such as Potters 6545 (Potters Industries), ground pumice (Smith Chemical and Wax of Savannah, Savannah, Ga.), or a combination thereof. Additional examples of the filler material include talc, silica, calcium carbonate, fiberglass, ground glass, diatomaceous earth, polyethylene, wood flour, titanium dioxide, white rubber, calcium sulfate, gold mica, silver mica, lead powder, iron, iron oxide, carbon, or any other filler known in the art. Useful inert fillers are capable of enhancing various specific properties of the finished molded part, such as density, frictional properties, coefficient of restitution, fire resistance, abrasion resistance, dielectric properties, and magnetic properties. In preferred embodiments of the polymer composition, the filler material ranges from about 0.1 to about 13 weight percent of the resin admixture, preferably from about 0.2 to about 11 weight percent of the resin admixture, and most preferably from about 0.5 to about 9 weight percent of the resin admixture. [0027] Preferred embodiments of the polymer composition may contain one or more plasticizer or diluent materials. The plasticizer material can be made from one or more plasticizers. Various plasticizers may be added to modify the physical properties of elasticity, hardness, and flexibility of the molded part. The plasticizers may be incorporated at levels of between about 0 and 40 percent by volume, depending on the type of polymer used in the resin admixture, and the specific properties the user wishes to achieve in the finished molded part. Preferred examples of the plasticizer material include 2,2-trimethyl-1,3-pentanediol-diisobutyrate, such as Eastman TXIB (Eastman Chemicals, Kingsport, Tenn.), a chlorinated paraffin hydrocarbon wax, such as Dover Chlorowax C-40 (Dover Chemicals, Dover, Ohio), dialkyl phthalate, such as BASF Palatinol 711-P (BASF Corporation), dibutyl phthalate, texanol ester alcohol, such as Eastman TEX (Eastman Chemicals), sucrose acetate isobutyrate, such as Eastman SAIB (Eastman Chemicals), dioctyl phthalate, dioctyl adipate, diisooctyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, oleic acid, alphamethylstyrene, benzoate ester, such as Velsicol Benzoflex 2088 (Velsicol Company, Rosemount, Ill.), hydrocarbon polystyrene resin, such as Eastman Piccolastic A-5 (Eastman Chemicals), urethane polyether polyol, polyoxyalkylene polyol, such as BASF Pluracol GP-730 (BASF Corporation), polyhydroxy amine, such as BASF Quadrol (BASF Corporation), or Bayer Multranil 9157 (Bayer Corporation, Pittsburgh, Pa.), or a combination thereof. In preferred embodiments of the resin admixture, the plasticizer material ranges from about 20 to about 35 weight percent of the resin admixture, preferably from about 25 to about 33 weight percent of the resin admixture, and most preferably from about 28 to about 31 weight percent of the resin admixture. [0028] Preferred embodiments of the modified epoxy resin may also contain one or more diluents, such as Cardiolite Diluent NC-700 (Cardiolite Company). In preferred embodiments of the polymer composition, the diluent ranges from about 0 to about 20 weight percent of the resin admixture, preferably from about 0 to about 15 weight percent of the resin admixture, and most preferably from about 0 to about 10 weight percent of the resin admixture. [0029] As shown in FIG. 1 , a preferred method of preparing the polymer composition begins with placing the reactants which form the polyurea gelled phase in separate containers. A first vessel 100 can hold the isocyanate, or Reactant A, and a second vessel 101 can hold the amine, or Reactant B. In addition, between about 45 and 65 percent by volume of the liquid reactants, such as the epoxy resin material, can be placed into the first vessel 100 . The remainder of the liquid reactants, such as the plasticizer or diluent material, can be placed into the second vessel 101 . A particulate filler may be added to either or both vessels. The contents of both the first vessel 100 and the second vessel 101 are then mixed in a mixing chamber 102 , which initiates the primary and secondary reactions. The preferred manner of this mixing is with an impingement mixer, but in cases where low density, hollow glass or plastic fillers are being used, some of these fillers carmot withstand the shear generated by the impingement mixer without breakage. In these cases, a motorized mechanical mixing chamber may be used in place of the impingement mixer. In cases where very low density hollow glass or plastic fillers are being used, and impingement or motorized mixing chambers would fracture or collapse the hollow spheres, a simple static mixing tube may be used. The main advantage to the impingement mixer is its low contained volume, which makes it possible to utilize a fast-reacting polyurea. For the mechanical mixer and the static mixing tube methods, a slower reacting gel phase must be used to prevent gelling of the material in the mixing device. Frequent flushing of mix heads may also be useful, but this may require excessive solvent use and result in higher material costs. [0030] Finally, the mixed fluids are poured into a mold 103 in any desired shape. Alternatively, the fluids can be poured onto a substrate or core (such as a bowling ball inner core) within a mold, thus creating an outer layer for the substrate or core. The present invention also pertains to a bowling ball prepared by this method. [0031] The polymer composition can be used in the manufacture of various polymeric molded parts. The polymer composition can be applied especially well to the manufacture of bowling balls, and particularly to the manufacture of bowling balls which incorporate various particulate fillers and plasticizers to enhance bowling ball performance. It is understood by those of skill in the art that current types of bowling ball manufacturing equipment can be used to produce bowling balls incorporating the polymer composition. Neither additional new equipment nor modifications to existing equipment is required in most cases in order to make use of the polymer composition. [0032] Bowling balls containing an inner core and an outer core are known in the art. In addition, it is understood by those skilled in the art that the polymer composition can be applied to any typical bowling ball utilizing conventional materials. Such conventional shell materials may include, but are not limited to, unsaturated polyesters, polyurethanes, and epoxies of various types. One or more inner cores or outer shells of the same or varying compositions may be used within the bowling ball and provided for in the same manner as for a bowling ball having a single inner core and a single outer shell or layer. Both the inner core and the outer shell may be manufactured of such materials as are known in the art. The polymer composition can be used in both the inner core and in the outer shell to restrict the movement of particulate matter through the core or shell and thus prevent undesirable density gradients from being formed. [0033] Although the polymer composition has been described with reference to specific embodiments, and specifically to bowling balls, the polymer composition is generally and widely useful and is applicable to many other embodiments and products other than bowling balls. This description should not be limited or construed in a limited manner, but rather should be considered to pertain to a very general process which may be useful for a wide range of embodiments requiring density gradient control of polymeric resin admixtures containing a wide variety of particulate fillers. Various embodiments will become apparent to those skilled in the art after reading the description. EXAMPLE 1 Example Resin Admixtures Used to Produce Example Polymer Compositions [0034] The Tables below show nine different resin admixtures which were mixed according to the methods described in order to produce examples of the polymer composition. TABLE 1-1 Resin Admixture A First Vessel Second Vessel Ingredient % (wt) Ingredient % (wt) Epoxy resin (Epon 828) 53.0 Filler material (Mica) 3.8 Isocyanate 1.2 Plasticizer (Eastman TXIB) 32.0 Amine 10.0 (Aminoethylpiperazine) [0035] TABLE 1-2 Resin Admixture B First Vessel Second Vessel Ingredient % (wt) Ingredient % (wt) Epoxy resin 56.0 Filler material (solid glass spheres) 3.8 (Epon 828) Plasticizer (Velsicol Benzoflex 2088) 27.5 Isocyanate 1.2 Amine (Aminoethylpiperazine) 11.5 [0036] TABLE 1-3 Resin Admixture C First Vessel Second Vessel Ingredient % (wt) Ingredient % (wt) Epoxy resin 56.0 Filler material (Potters Q-300) 4.0 (Epon 828) Plasticizer (Eastman TXIB) 27.3 Isocyanate 1.2 Amine (Aminoethylpiperazine) 11.5 [0037] TABLE 1-4 Resin Admixture D First Vessel Second Vessel Ingredient % (wt) Ingredient % (wt) Epoxy resin (Epon 828) 53.0 Filler material (Pumice) 3.0 Isocyanate 1.5 Plasticizer (Eastman TXIB) 33.5 Amine 9.0 (Aminoethylpiperazine) [0038] TABLE 1-5 Resin Admixture E First Vessel Second Vessel Ingredient % (wt) Ingredient % (wt) Epoxy 58.0 Filler material (Potters Q-300) 4.0 resin (Epon 828) Filler material (Rubber) 1.0 Isocyanate 1.2 Plasticizer (Eastman TXIB) 25.8 Amine (Aminoethylpiperazine) 10.0 [0039] TABLE 1-6 Resin Admixture F First Vessel Second Vessel Ingredient % (wt) Ingredient % (wt) Epoxy 58.0 Filler material (Potters 6014) 1.2 resin (Epon 828) Filler material (Rubber) 9.0 Isocyanate 1.2 Plasticizer (Eastman TXIB) 20.6 Amine (Aminoethylpiperazine) 10.0 [0040] TABLE 1-7 Resin Admixture G First Vessel Second Vessel Ingredient % (wt) Ingredient % (wt) Epoxy 59.0 Filler material (Rubber) 9.0 resin (Epon 828) Plasticizer (Eastman TXIB) 18.3 Isocyanate 1.9 Amine (Aminoethylpiperazine) 11.8 [0041] TABLE 1-8 Resin Admixture H First Vessel Second Vessel Ingredient % (wt) Ingredient % (wt) Epoxy resin (Epon 828) 55.0 Plasticizer (Eastman TXIB) 33.9 Isocyanate 2.1 Amine 9.0 (Aminoethylpiperazine) [0042] TABLE 1-9 Resin Admixture I First Vessel Second Vessel Ingredient % (wt) Ingredient % (wt) Epoxy 57.0 Filler material (Potters 6545) 0.29 resin (Epon 828) Filler material (Rubber) 9.0 Isocyanate 1.7 Plasticizer (Eastman TXIB) 20.51 Amine (Aminoethylpiperazine) 11.5
A polymer composition in a thermosetting resin admixture having a subcomponent gelled phase or polyurea. The gelled phase or polyurea is capable of trapping particles of widely differing particle densities within the polymer composition, thereby preventing these particles from either sinking or floating. The polymer composition can be cured in the normal fashion, yielding a useful filled polymer molded part with a substantially homogeneous density of particulate filler throughout. The gelled polyurea phase of the resin admixture is generated in situ during the mixture of the components of the thermosetting resin admixture. The polymer composition is particularly useful for the production of bowling balls, but may be used in any molded polymer parts.
2
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to copolyamides from aliphatic diamines, particularly hexamethylene diamine and either mixtures of adipic acid and terephthalic acid, or mixtures of adipic acid, terephthalic acid and isophthalic acid. In particular, it relates to copolyamides having a melting point(T m ) below 320° C., a glass transition temperature(T g ) between 100° C. and 120° C., and mechanical properties similar to nylon 66. 2. Description of the Prior Art 100% hexamethylene terephthalamide(6T) polymer has a high T g and also a T m (about 370° C.) too high for it to be melt processed. While replacing a portion of the terephthalic acid with isophthalic acid lowers the T m while preserving the high T g , the resulting 6T/6I (hexamethylene terephthalamide hexamethylene isophthalamide) copolymer has less crystallinity. Accordingly, copolyamides obtained from 66 (hexamethylene adipamide), 6T, and 6I in various ratios have been developed and applied in different industrial fields. For example, Japan Patent No. 46-18809 (71018809) discloses a copolyamide obtained from 10-50 wt% of hexamethylene adipamide(66), 10-50 wt% of hexamethylene terephthalamide (6T) and 10-55 wt% of hexamethylene isophthalamide (6I). The copolyamides are suitable for use as fibers. Japan Laid open Patent No. 52-85516 (77085516) discloses a copolyamide fiber which is obtained from 20-70 wt% of hexamethylene adipamide(66), 15-45 wt% of hexamethylene terephthalamide (6T) and 15-35 wt% of hexamethylene isophthalamide (6I). Japan Patent No. 46-28218 (71028218) discloses a complex polyamide fiber which is manufactured from a copolyamide prepared from 10-80 wt% of hexamethylene adipamide(66), 10-50 wt% of hexamethylene terephthalamide (6T) and 10-55 wt% of hexamethylene isophthalamide (6I). U.S. Pat. No. 4,238,603 discloses a copolyamide fiber which is obtained from 2-15 wt% of hexamethylene adipamide, 45-68 wt% of hexamethylene terephthalamide, and 30-40 wt% of hexamethylene isophthalamide. Japan Pat. No. 68-067801 discloses a fiber prepared from a copolyamide consisting of 10-80 wt% of hexamethylene adipamide, 10-65 wt % of hexamehtylene terephthalamide, and 10-55 wt% of hexamethylene isophthalamide. U.S. Pat. No. 4,218,509 discloses a copolyamide fiber which is manufactured from at least 50 wt% of hexamethylene adipamide, 20-40 wt% of hexamethylene terephthalamide, and 2-20 wt % of hexamethylene isophthalamide. U.S. Pat. No. 4,521,484 discloses the synthesis of copolyamide filaments which are manufactured by using at least 60 wt% of hexamethylene adipamide, 15-30 wt% of hexamethylene isophthalamide and 5-10 wt% of hexamethylene terephthalamide. U.S. Pat. No. 4,603,166 and U.S. Pat. No. 4,603,166 disclose crystalline copolyamides having high heat deflection temperature, which are prepared from hexamethylene diamine, adipic acid, terephthalic acid and isophthalic acid at a mole ratio of about 100:5-35:65-95: 0-25. U.S. Pat. No. 4,246,395 discloses a fiber-forming polyamide consisting of 5-20 wt% of hexamethylene adipamide, 40-75 wt% of hexamethylene terephthalamide and 20-40 wt% of hexamethylene isophthalamide. The fiber-forming polyamide has a melting point below 320° C., a glass transition temperature above 115° C. and good thermal stability. U.S. Pate. No. 4,268,661 discloses copolyamides having a glass transition temperature of 140° C.-170° C. The copolyamides are suitable as engineering plastics and are manufactured from 0-15 mole% of hexamethylene adipamide, 0-50 mole % of hexamethylene terephthalamide and 50-100 mole% of hexamethylene isophthalamide. Japan Patent Nos. 60-32980(94-32980) and 60-32979(94- 32979) disclose crystalline polyamides for injection molding. The polyamides comprise 30-95 wt% of hexamethylene adipamide, 0-40 wt% of hexamethyene terephthalamide, and 5-30 wt% of hexamethylene isophthalamide. Japan Patent No. 31-26725 discloses aromatic copolyamides which are produced by polymerizing adipic acid, terephthalic acid, isophthalic acid and hexamethylene diamine in the presence of sodium hypophosphite. Japan Patent No. 3007761 discloses polyamides prepared from (a) a dicarboxylic acid consisting of 0-70 mole% of adipic acid, 30-100 mole % of terephthalic acid, and 0-40 mole % of isophthalic acid and (b) hexamethylene diamine. The polyamides thus prepared are highly resistant to heat, water and chemicals and have high mechanical strength. German Patent DE 3506656(1986) discloses copolyamides prepared from adipic acid, terephthalic acid, isophthalic acid and hexamethylene diamine with a weight ratio of adipic acid to mixture of terephthalic acid and isophthalic acid of 30-51:48.5-70. The weight ratio of terephthalic acid to isophthalic acid is 48.5-60:40-51.5. The copolyamides have higher T g and lower water absorption. European Patent No. 121984 discloses a copolyamide comprising (A) hexamethylene adipamide, (B) hexamethylene terephthalamide and (c)hexamethylene isophthalamide wherein the mole ratio of the dicarboxylic acid moieties in (A), (B) and (C) is 5-35:5-35:60-90. An injection molding composition comprising the above copolyamides and 10-60 wt% of glass fibers or beads and/or mineral or graphite fibers has a heat deflection temperature of 240° C.-305° C. Japan Laid Open Patent No. 6-287299 discloses a continuous process for preparing copolyamides. The copolyamides comprise the following recurring units: ##STR1## wherein the weight ratio of (I)/(II) is 55-80/20-45, (I)/(III) is 20-80/20-80 and (I)/(IV) is 55-90/10-45. The copolyamides are heat resistant and have lower water absorption. Japan laid open Patent No. 06-287,300 discloses a copolyamide comprising the same recurring units (I), (II), (III) and (IV) and having the same weight ratio of (I)/(II), (I)/(III) and (I)/(IV). The copolyamide is crystalline and heat resistant. European Patent No. 0 409 666 A2 discloses a polyamide composition comprising the following recurring units: ##STR2## wherein the mole ratio of the dicaroxylic acid moieties in the A, B, and C units is about 0.5-49.5/0-20/0.5-49.5 and wherein R is a divalent radical comprising ##STR3## and --(CH 2 ) 6 -- in a mole ratio of about 0.5-50/49.5-0. The polyamide compositions have a glass transition temperature of 90° C. or greater and an oxygen transmission rate of about 2.0 cc-mil/100 in 2 -day-atm or less. European Patent No. 0 291 096 discloses a novel crystalline copolyamide having high heat deflection temperature. The copolyamide comprises the following recurring moieties: ##STR4## wherein the mole ratio A:B:C is 60-90:35-5: 35-5. SUMMARY OF THE INVENTION It is an object of the invention to provide a copolyamide having a melting point(T m ) below 320° C., a glass transition temperature(T g ) of 100°-120° C., and mechanical properties similar to nylon 66. The object of the invention is attained by providing a copolymaide comprising the following recurring units: ##STR5## wherein the mole ratio of the dicarboxylic acid moieties in the (A), (B), (C) units is 30-70:30-60:0-20, and n 1 , n 2 and n 3 are integer of 2-14. The copolyamides of the invention can be used as engineering plastics. For example, they can be processed in usual plastic machines, e.g. injection molding apparatus, extruder to form molded objects or laminates to be used in the production of automobile parts, gears, bearings, and electronic and electrical parts, and casters etc. The copolyamides are also suitable for being spun into fibers, and filaments. DETAILED DESCRIPTION OF THE INVENTION The preparation of the copolyamides of the invention can be carried out in two steps. In the first step, a polyamide prepolymer is prepared in a stirred reactor which are suitable for processing materials of high viscosity. Feed materials consisting of dicarboxylic acids (terephthalic acid, adipic acid and isophthalic acid in the desired ratios), diamines (as commonly used herein aqueous hexamethylene diamine), and any additives are charged to the reactor at an external temperature of about 150° C. The water content is about 5 to 25 percent by weight based on the total amount of the reactants. The reactor is then purged with nitrogen gas or other inert gas and the polymerization mixture is then raised to between about 240° C. to 310° C. During the preparation process, the pressure, principally steam pressure is maintained between 4-5 kg/cm 2 . Once the water formed during the prepolymerization process reaches about 30% of the total water amount, the pressure is reduced to about 1 kg/cm 2 over a period of 3 to 30 minutes. The prepolymer is then allowed to flow out of the reactor into iced water, and collected. The second step is the final polycondensation and can utilizes either a conventional stirred reactor or a twin-screw extruder reactor (the so-called reactive extrusion method). The final polycondensation step, when using a conventional stirred reactor, is conducted at an external temperature of about 360° C. and a vacuum of about 70 cm-Hg. The final polycondensation step, when using a twin-screw extruder as a reactor, has good heat conductivity, can obtain extensive agitation and provide multi-stage heating, evacuating and venting during the reaction, and thus enables continuous polycondensation in a shorter reaction time and allows these high melting resins to be easily handled. The reactive extrusion method is conducted at a temperature of from 240°-280° C. and a vacuum of about 60 cm-Hg. The invention will now be described in greater detail with reference to the following non-limiting examples. EXAMPLE 1 A. preparation of prepolymers A 2-liter reactor fitted with a stirrer was cleaned and purged with nitrogen gas. 120 g of hexamethylene diamine(HMDA) was dissolved in a 70° C. water bath and distilled water was added to the dissolved HMDA. The amount of the distilled water was 17 percent by weight of the dissolved HMDA. The mixture was then poured into the reactor and then a suitable amount of adipic acid (AA) (the mole ratio of AA HMDA was 1:1.03) and 0.1 percent by weight of sodium hypophosphite was added. The reactor was then purged five times with nitrogen gas. Thereafter, the external temperature of the reactor was first set at 230° C., then raised to 250° C. after 10 minutes and maintained for 30 minutes, and then raised to 280° C. and maintained for 30 minutes and subsequently raised to 310° C. and maintained for 30 minutes, and finally raised to 340° C. During the heating process, the pressure was maintained at 4-5 kg/cm 2 . When the water amount formed reached 60 ml (about 30 % of the total water amount), the pressure was reduced to 1 kg/cm 2 . At that time, the total water amount formed was 75 ml(70% of the total water amount). The prepolymer thus formed was then allowed to flow out into ice water. B. preparation of the final polyamide A steel tube immersed in a tin liquid heated to 360° C. was used as a reactor for this step. 0.5-1 g of dried prepolymer was placed in the steel tube, and the steel tube was placed in the tin liquid under a vacuum of 70 cm-Hg. When the internal temperature of the steel tube reached a temperature 20° C. lower than the melting point of the sample, the steel tube was taken out and placed in ice water for cooling. When the temperature of the steel tube fell below 100° C., the resulting polyamide sample was taken out for analysis. C. measurement of the relative viscosity of the sample polyamide The viscosity of the resulting polyamide was measured in a Cannon #150 three-opening viscosmeter immersed in a thermostat. The temperature of the thermostat was maintained at 30°±0.1° C., the solvent used was phenol tetrachloroethane(6/4 w w), and the concentration of the polyamide was 0.5 g/dl. The relative viscosity (R.V.) was 1,0-1.5. D. measurement of Tg by Rehovibron analysis 1-5 g of dried polymer was compressed into a film of 0.005-0.01 cm by a hot press. The film was then cut into test strips(3-4 cm×0.3 cm). Each test strips was heated from room temperature to 200° C. at a rate of 2° C./min and the frequency was set at 11 Hz. The T g of each test strips was recorded and shown in Table 1. E. measurement of T m by D.S.C. analysis 6-8 mg of sample was prepared and first heated from room temperature to 300° C. in a D.S.C. at a heating rate of 20° C./min. When the temperature reached 300° C., the sample was cooled to room temperature at a cooling rate of 5° C./min, and then heated to 350° C. at a rate of 20° C./min. T m was recorded and shown in Table 1. EXAMPLE 2 The same procedures were used as in Example 1, except that the adipic acid(AA) was replaced with a mixture of adipic acid, terephthalic acid(TA) and isophthalic acid(IA) having a mixing ratio as indicated in Table 1. The synthesized copolyamides all had a R.V larger than 1.6, and their Tg and Tm are summarized in Table 1 below. TABLE 1______________________________________Diacid composition mole ratio T.sub.g (°C.) Tm(°C.)______________________________________AA 100 70 265AA/TA 60/40 105 278AA/TA 50/50 112 306AA/TA/IA 50/45/5 112 282AA/TA/IA 45/45/10 115 275AA/TA 40/60 108 325AA/TA/IA 30/45/15 118 287______________________________________ EXAMPLE 3 A. preparation of prepolymers The same procedures of Example 1 and Example 2 were used, except that the reactor was changed to a 50-liter reactor to obtain three prepolymers in which the first prepolymer was prepared from AA and HMDA, the second prepolymer was prepared form HMDA and a mixture of AA/TA/IA having a mixing ratio of 50/45/5, and the third prepolymer was prepared from HMDA and a mixture of AA/TA having a mixing ratio of 60/40. B. preparation of the final copolyamides In this example, a twin-screw extruder reactor was used to prepare the final copolyamides. The three prepolymers were dried, pulverized and then fed into a twin-screw extruder, the Zawa 45 mm extruder. The process conditions employed in the twin-screw extruder are presented in Table 2 below. TABLE 2__________________________________________________________________________ Zone vacuum Die temp.Screw Speed (rpm) Zone temperature (°C.) degree (cm-Hg) (°C.)__________________________________________________________________________180 1 2 3 4 5 6 7 8 1 2 3 270 120 240 265 273 290 280 278 270 60 60 60__________________________________________________________________________ C. Measurements of T m and T g T m and T g of the resulting copolyamides were measured by the same procedures as used in Example 1, and the results are summarized in Table 3. D. Measurement of physical properties Test specimens were prepared by using a single-screw injection molding machine (Niigata-Stubba). The process conditions of the preparation are summarized below. diameter of the screw: 30 mm barrel temperature: 255° C.-256° C. nozzel temperature: 274° C. molding temperature: 110° C. injection pressure: 3 kg/cm 2 keep pressure time: 10 sec cooling time: 50 sec mold open time: 1.2 sec screw speed: 100 rpm The tensile strength, flexural strength and flexural modulus of the test specimens were tested in accordance with ASTM-D638, and the results are summarized in Table 3 below. TABLE 3______________________________________Composition of diacid AA AA/TA/IA AA/TA______________________________________mole ratio 100 50/45/5 60/40Tensile strength 750 910 878(kg/cm.sup.2)Flexural strength 1200 1330 1276(kg/cm.sup.2)Flexural modulus 27,000 29684 28820(kg/cm.sup.2)Tg (°C.) 45 112 105Tm (°C.) 265 282 278______________________________________ As can be seen from Table 3, the copolyamide of the 15 invention has a Tm of less than 300° C., a Tg between 100°-120° C. and equally good or better mechanical properties than nylon 66.
A copolyamide composition prepared from hexamethylene diamine and either mixtures of adipic acid and terephthalic acid, or mixtures of adipic acid, terephthalic acid and isophthalic acid, has a melting point below 320° C., a glass transition temperature between 100° C. and 120° C. and physical properties similar to nylon 66.
3
BACKGROUND OF THE INVENTION [0001] 1. Field of Invention [0002] The invention relates to accessories for smoking tobacco, and more particularly to a cigarette case having an improved cigarette ejection mechanism for ejecting one or two cigarettes in a dispensing operation. [0003] 2. Description of Related Art [0004] There have been numerous suggestions in prior patents for ejecting a cigarette from a cigarette case. For example, U.S. Pat. No. 5,265,717 discloses a cigarette case for automatically lighting and ejecting a cigarette contained therein. While the '717 patent can accomplish its objective, its gear mechanism and conveyor are relatively complex in constructions, resulting in an increase in the manufacturing cost. Thus, continuing improvements in the exploitation of cigarette case having a simple cigarette ejection mechanism are constantly being sought. SUMMARY OF THE INVENTION [0005] It is therefore one object of the invention to provide a cigarette case having a cigarette ejection mechanism for ejecting one cigarette in a dispensing operation. [0006] It is another object of the invention to provide a cigarette case having a cigarette ejection mechanism for ejecting two cigarettes in a dispensing operation. [0007] The above and other objects, features and advantages of the invention will become apparent from the following detailed description taken with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0008] FIG. 1 is an exploded view of cigarette case incorporating a first preferred embodiment of first pusher according to the invention; [0009] FIG. 2 is a view similar to FIG. 1 but viewed from an opposite angle; [0010] FIG. 3 is a perspective view of the first pusher; [0011] FIG. 4 is a top plan view of the first pusher; [0012] FIG. 5 is a side elevation of the first pusher; [0013] FIG. 6 is a detailed view of the area in circle K of FIG. 5 ; [0014] FIG. 7 is an enlarged view of the ejector lid and the torsion spring of FIG. 1 ; [0015] FIG. 8 is a perspective view of the second pusher; [0016] FIG. 9 is a side elevation of the second pusher; [0017] FIG. 10 is a side elevation of the V-shaped member compressed as an I-shaped one; [0018] FIG. 11 is a longitudinal sectional view of the outer casing of FIG. 2 ; [0019] FIG. 12 is a top plan view of the assembled cigarette case with its top being removed to show fully packed cigarettes therein; [0020] FIG. 13 is a top plan view of a second preferred embodiment of first pusher according to the invention; [0021] FIG. 14 is a top plan view of the assembled cigarette case incorporating the second preferred embodiment of first pusher with its top being removed to show fully packed cigarettes therein; [0022] FIG. 15 is a top plan view of a third preferred embodiment of first pusher according to the invention; [0023] FIG. 16 is a top plan view of the assembled cigarette case incorporating the third preferred embodiment of first pusher with its top being removed to show fully packed cigarettes therein; [0024] FIG. 17 is a perspective view of the cover; [0025] FIG. 18 is a longitudinal sectional view of the assembled cigarette case of FIG. 2 for showing a cigarette dispensing operation; [0026] FIG. 19 is a detailed view of the area in circle A of FIG. 18 ; [0027] FIG. 20 is a perspective view of the cigarette case of FIG. 18 ; and [0028] FIG. 21 depicts steps of packing cigarettes in the cigarette case of the invention and dispensing same. DETAILED DESCRIPTION OF THE INVENTION [0029] Referring to FIGS. 1 to 21 , a cigarette case in accordance with the invention comprises an outer casing 1 having one open side and an open bottom. The outer casing 1 comprises a rectangular opening 11 at one end of the top, two parallel slots 12 at an intermediate portion of the other side, a rectangular recess 14 on an inner surface of either rear wall or front wall extending from one side to terminate at either stop shoulder 15 proximate the slots 12 , two sets of two spaced first troughs 13 in which the recess 14 is formed between the first troughs 13 of either set and the first troughs 13 of the same set are formed on the front or rear edge of one side, two second troughs 17 each at the bottom of the inner surface of either the rear wall or the front wall, a first tab 18 at the bottom of the other side, a first hole 19 on the top in communication with the opening 11 , two first through holes 20 at both corners of the opening 11 distal the other side of the opening 11 with the first hole 19 formed therebetween, and two second holes 26 at both ends of one top corner. [0030] The cigarette case further comprises a first pusher 4 having a transverse section of U. For example, the first pusher 4 of the first preferred embodiment comprises three longitudinal grooves 41 substantially having a transverse section of half-circle in which one side 44 of either side groove 41 further extends a predetermined distance so as to have a length greater than a radius of a cigarette 9 contained therein, a plurality of spaced, transverse, arcuate ribs 42 longitudinally formed on each groove 411 , a longitudinal ridge 43 formed between two adjacent grooves 41 , and two flush second tabs 45 on an outer surface adapted to slidably pass the slots 12 to project out of the other side of the outer casing 1 . By configuring as above, it is possible of preventing the contained cigarettes 9 from engaging the inner surfaces of the outer casing 1 so as to facilitate movement in the outer casing 1 and increasing friction between the cigarettes 9 and the grooves 41 so as to prevent the cigarettes 9 from vibrating. Both features can facilitate a smooth cigarette dispensing as detailed later. [0031] The cigarette case further comprises a disc-shaped trigger member 8 having two flush third holes 81 adapted to lockingly receive the second tabs 45 so that the first pusher 4 can slide upward or downward by pulling up or pressing down the trigger member 8 as detailed later. [0032] The cigarette case further comprises an ejector lid 6 dimensioned and shaped to fit snugly on the opening 11 . The rectangular ejector lid 6 comprises a first channel 62 along one side, and a slit 61 opposing the first hole 19 ; a torsion spring 7 having one end 71 inserted into the slit 61 and retained therein, and the other end 72 inserted into the first hole 19 and retained therein; and a first pin 63 inserted through the first through holes 20 , the first channel 62 and the torsion spring 7 to mount the ejector lid 6 as a hinged one which is adapted to open or close by rotating about the first pin 63 with the torsion spring 7 always trying to pull the open ejector lid 6 back to its original closed position as detailed later. Also, the ends 71 , 72 of the torsion spring 7 are easy to rotate around the center line of the torsion spring 7 so that the cigarettes 9 can be easily dispensed by opening the ejector lid 6 . [0033] The cigarette case further comprises a cross-shaped second pusher 3 including two rectangular wings 31 , a central, longitudinal, interrupted furrow 32 , an intermediate, transverse cavity 35 parallel with the wings 31 and crossing the furrow 32 , and two second through holes 33 at both sides of the furrow 32 substantially abutting the cavity 35 . [0034] The cigarette case further comprises an L-shaped cover 2 including a bottom 2 A, a wall 2 B perpendicular to the bottom 2 A, and a second channel 28 on a top of the wall 2 B. The cover 2 further comprises two flush ears 23 having a third through hole (not numbered) raised on an inner surface of the wall 2 B, a slit 21 on an inner surface of the bottom 2 A proximate the open end of the bottom 2 A, two opposite third tabs 25 on intermediate portions of front and rear sides of the bottom 2 A respectively, and two sets of two spaced fourth tabs 22 on front and rear sides of the wall 2 B respectively. [0035] The cigarette case further comprises a resilient V-shaped member 5 including a hollow first cylinder 51 at a first end, a hollow second cylinder 52 at an opposing second end, and a hollow third cylinder 53 at a joining point of both cylinders 51 , 52 . [0036] The first cylinder 51 is fitted in the cavity 35 so that inserting a second pin 34 through the second through holes 33 and the first cylinder 51 will allow the first cylinder 51 to pivot a limited angle with respect to the second pin 34 . The second cylinder 52 is fitted between the ears 23 so that inserting a third pin 24 through the third through holes of the ears 23 and the second cylinder 52 will allow the second cylinder 52 to pivot a limited angle with respect to the third pin 24 . Further, inserting a fourth pin 27 through the second channel 28 into the second holes 26 will mount the cover 2 as a hinged one with respect to the outer casing 1 . [0037] In an assembly state of the cigarette case the first tab 18 is inserted into the slit 21 for releasably fastening therein, the third tabs 25 are inserted into the second troughs 17 for releasably fastening therein, and the fourth tabs 22 are inserted into the first troughs 13 for releasably fastening therein. Further, the second pusher 3 is adapted to slide substantially from a first position proximate the wall 2 B to a second position coincident at the stop shoulders 15 (i.e., when the wings 31 slidable relative to the recess 14 are stopped by the stop shoulders 15 in its sliding movement) or vice versa. [0038] By configuring as above, for example, a pushing of the cigarettes 9 toward the second pusher 3 will push one arm (i.e., the portion of the V-shaped member 5 from the first cylinder 51 to the third cylinder 53 ) of the V-shaped member 5 toward the wall 2 B and push the other arm (i.e., the portion of the V-shaped member 5 from the second cylinder 52 to the third cylinder 53 ) of the V-shaped member 5 toward the second pusher 3 when packing cigarettes 9 in a space defined by the first pusher 4 and the second pusher 3 . [0039] A cigarette packing operation of the invention will be described in detail below by referring to FIG. 21 specifically. First, open the cover 2 . Next, remove about two-thirds of a cigarette package to expose most portions of cigarettes 9 . Next, pack the cigarettes 9 in the space defined by the second pusher 3 and the first pusher 4 by pushing the second pusher 3 toward the wall 2 B and pushing the first pusher 4 toward the other side of the outer casing 1 until the wings 31 are stopped by the stop shoulders 15 . Finally, close the cover 2 onto the outer casing 1 . [0040] A cigarette dispensing operation of the invention will be described in detail below by referring to FIGS. 18 and 20 specifically. First, pull up the trigger member 8 and thus the first pusher 4 until the trigger member 8 is stopped by the top ends of the slots 12 . The upward moving cigarettes (e.g., two cigarettes) 9 will push the ejector lid 6 upward by pivoting about the torsion spring 7 until the filter portions of the cigarettes 9 are exposed. After removing the two cigarettes 9 , the next two adjacent cigarettes 9 will occupy the empty space previously occupied by the removed cigarettes 9 as a result of pushing the cigarettes 9 toward the first pusher 4 by the second pusher 3 which is in turn pushed by the V-shaped member 5 . A person may then press the trigger member 8 downward to return to its original position in which the next two cigarettes 9 are retained in the grooves 14 again. As an end, the ejector lid 6 automatically closes the opening 11 due to the exertion of the returning force of the torsion spring 7 . [0041] Referring to FIGS. 13 and 14 specifically, a second preferred embodiment of first pusher 4 according to the invention is shown. The characteristics of the second preferred embodiment of the first pusher 4 are that two rows of cigarettes 9 are adapted to pack in the space defined by the first pusher 4 and the second pusher 3 since the first pusher 4 has only two grooves 41 . In comparison, the first pusher 4 of the first preferred embodiment has three grooves 41 . Only one cigarette 9 can be removed in one dispensing operation. [0042] Referring to FIGS. 15 and 16 specifically, a third preferred embodiment of first pusher 4 according to the invention is shown. The characteristics of the third preferred embodiment of the first pusher 4 are that one row of cigarettes 9 are adapted to pack in the space defined by the first pusher 4 and the second pusher 3 since the first pusher 4 has only one groove 41 . Thus, only one cigarette 9 can be removed in one dispensing operation. [0043] The cigarette case can be formed of a metal material or a non metal material. [0044] While the invention herein disclosed has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.
A cigarette case includes an outer casing hingedly secured to a cover; a U-shaped first pusher proximate the other side of the outer casing and including at least one longitudinal groove or arcuate section; a trigger member secured onto the other side of the outer casing; a spring biased hinge-type ejector lid on a top corner of the outer casing; a sliding cross-shaped second pusher; and a sliding V-shaped member resiliently interconnecting the second pusher and the cover. A plurality of cigarettes are contained in a space defined between the first pusher and the second pusher such that pulling up the trigger member a predetermined distance will lift the first pusher to cause the at least one cigarette engaged therewith to open the ejector lid.
0
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a protective glove and its palm-fingers unit for hockey, lacrosse and other similar sports gloves. Specifically the invention relates to hockey, lacrosse and sports gloves in which the palm-finger unit for holding the shaft, stick, etc., can be easily removed and replaced quickly and easily while having a protective fly cover to cover a zipper attachment when it is installed in the glove. [0003] 2. Prior Art [0004] During hockey and lacrosse when a player uses a pair of gloves for a prolonged period of time, the palm-finger area of the glove gets worn, wet, and reduces the players ability to hold the shaft, stick etc. with a good sensitivity within the player's hand allowing a comfortable feeling between shaft, stick and the player fingers and palm. [0005] The players require this sensitivity to maintain skillful stick or ball handling which is essential in hockey and lacrosse. This all must be in a glove that is comfortable and not have exposed elements such as a zipper when the glove is being used. [0006] In hockey and lacrosse gloves, the portion on the back of the glove is usually protected with internal padding and is less susceptible to damage from the elements such as water, ice, grass and wear during conventional use. The front or palm-finger unit of the glove exhibits wear to a much greater extent during use due to constant engagement with the shaft, stick etc. Consequently, the palm-finger area of these hockey and lacrosse gloves is more likely to abrade and tear, or get brittle than the back of the glove. [0007] Therefore, the palm-finger area of a glove is generally the determining factor of the durability, life and or legality of wearing according to the rules of the hockey and lacrosse gloves and the like. [0008] U.S. Pat. No. 5,329,639 to Aoki discloses an ice hockey glove which addresses some of these issues. The ice hockey glove in Aoki patent discloses a hockey glove with a removable palm area at peripheral edges of the glove. The attaching means is a zipper installed at peripheral edges of the ice hockey gloves front and back member. Having an a zipper at peripheral edges as shown suffers in the shape, and feel in the finger area, which becomes abnormal and the internal area which touches the fingers is bothersome—not comfortable. Another major problem is that it leaves exposure of the attachment zipper to outside elements. This leads to exposure from other sticks, shafts during play leading to quick failure. Another major failing of the Aoki patent is that it leaves exposure of the attachment zipper to other players which are undesirable in these sports. Additionally, the attachment of the back padding to the exterior side of the glove may lead to padding failure. This makes the back area less durable and susceptible to outside elements. This would also fail to conform to the configuration of the users hand as it gets damaged or comes off and possibly failing to adequately protect the users. Additionally the wrist closure mechanism suffers as it takes too long to use and has too many pieces that must be engaged before using. Additionally, if the player is required to (must) put their hand in the glove in order to close the cuff area, makes it more difficult and less desirable to operate and function. The time frame is also increased which is less desirable. In this case, one only has the ability to close the mechanisms with the opposite hand instead of the dexterity of using two hands. This suffers in function. It is also more costly to produce. [0009] U.S. Pat. No. 3,605,117 to Latina discloses an ice hockey glove which addresses some of the issues. The hockey glove of the Latina patent discloses a hand receiver portion or an inner glove which is attached to a padded back portion at the ends of the finger stalls and the outer sides of the palm area, but otherwise remains detached from the inner glove. The inner glove is coupled to the padding through lacing. Consequently, when the face of the inner glove wears out, the lacings need to be withdrawn and a new inner glove installed, thereby allowing reuse the back padding. The Latina patent suffers from the disadvantage that it does not allow for quick replacement of the inner glove. Replacing the entire glove of the Latina patent is a time consuming procedure requiring the user to remove and replace all of the laces in the hockey glove. Additionally, the replacement of the entire inner glove portion in the Latina patent is not most efficient procedure since only the palm portion of the glove is generally damaged. Additionally, the attachment of the back padding to the glove at only distinct points may lead to the padding failing to conform to the configuration of the users hand and possibly failing to adequately protect the users in certain positions. OBJECTS OF THE INVENTION [0010] An object in the present invention is to overcome the aforementioned drawbacks of the prior art. [0011] Additionally, an object of the present invention is to provide hockey, lacrosse players and the like, with a desirable, usable, quick efficient and economical glove with a palm-finger unit replacement that also has protection for the attachment means and protects the players from contact with the attachment means. [0012] Other objects which become apparent from the following description of the present invention. SUMMARY OF THE INVENTION [0013] In keeping with these objects and others which may become apparent, the present invention is a new improved version of a two piece, connector joined sports glove, such as hockey, lacrosse and other sports gloves. The sports glove of the present invention features a joining connector, such as a zipper, set of snaps or other suitable attachment, covered by a fly cover. The zipper attaches the front palm with fingers portion to the glove portion. The fly cover protects the zipper attachment from damage caused by impact from the sports mentioned and protects the players in these sports from exposed zippers. [0014] This development also leads to a better feeling glove with more comfort, a normal look and a non exposed zipper. The fly cover can be the same material as the front palm-finger area or it can be different material. It can also be a combination of materials. It can be made of any suitable material used to make gloves or a combination of any suitable material or materials. [0015] In the preferred embodiment the fly cover can match the finger material or it can be different. The fly cover can be part of the front palm-finger portion in the sports glove such as hockey and lacrosse and the like. The fly cover can go from the glove portion (side) to the front palm side to cover the zipper. The fly cover can be a combination of the glove side and the front palm-finger side portions. The fly cover can be from the front palm side of the glove portion (side) to the glove portion. The percentage of each can be any percentage that can be feasible if one uses a combination of glove and front palm portions to form the fly cover. [0016] The fly cover can be different directions on different parts of the gloves if desired. The fly can overlap the nearest material that it is trying to meet. The fly can also be just shy of meeting the material it is trying to meet. [0017] The preferred embodiment would have the fly-cover cover the zipper as much as possible. Other embodiments may have less than the full coverage; however, anything covering at least 50 percent of the zipper would be preferable. [0018] The fly cover can go from left to right or right to left or any combination of these. The fly cover can go up to down or down to up or any combination of these. The fly cover can be any direction or a combination of directions. The fly cover can be any suitable material or a combination of suitable materials. [0019] The zipper can be made of any suitable material or materials. Examples include plastic, nylon, synthetic, polymer materials, metal, ferrous or non ferrous material, carbon fiber or any suitable material or combination of materials. The fly can be made from any suitable material or a combination of materials. The fly can be made from one piece of material or it can be made of multiple pieces. [0020] The fly cover material can be fabric type material, either synthetic or natural, such as leather, synthetic leather, suede, synthetic suede, Nash, micro fiber type material, VELCRO® hook and loop fastener, any natural or synthetic material or combination of materials and fibers that can be used in this industry for gloves. The fly cover can be any color or combination of colors. [0021] The zipper can be made from any suitable material or combination of materials. The fly can be cut, formed, molded, cast, forged, pressed, sewn or use any known manufacturing method or methods to make it. [0022] The zipper can be made from any suitable material or combination of materials. The zipper can be sewn, molded, pressed, cast, forged, formed, cut or be made by any known manufacturing method or combination of methods or manufacturing techniques. The attachment of the zipper and fly cover can be sewn, glued, bonded or use any suitable bonding technique or any combination of techniques. [0023] The zipper can be installed on the front palm unit in any feasible position-possible position. The preferred embodiment would have the zipper teeth at least slightly away from the back of the front palm units —finger receptacle edges. [0024] The zipper attachment on the glove side can be installed toward the middle of the fingers, toward the back of the fingers or toward the front of the fingers or any feasible position that will allow the operation and comfort for the fingers. On the preferred embodiment, the continuation of the zipper toward the sides of the hand and cuff would be toward the outer portion of the glove unit. The preferred embodiment would have some material between the edge of the finger unit and the zipper. BRIEF DESCRIPTION OF THE DRAWINGS [0025] The present invention can best be understood in connection with the accompanying drawings. It is noted that the invention is not limited to the precise embodiments shown in drawings, in which: [0026] FIG. 1 is a front perspective view of the zipper attached sports glove with fly cover protection of the present invention; [0027] FIG. 2 is a close up detailed view thereof; [0028] FIG. 3 is a close up detailed view of an alternative embodiment thereof; [0029] FIG. 4 is a detailed view of a further alternative embodiment thereof; [0030] FIG. 5 is a front perspective of another embodiment for one hand of a pair of a zipper-attached front palm units according to the present invention; [0031] FIG. 6 is a rear perspective view thereof; [0032] FIG. 7 is a front perspective view thereof; [0033] FIG. 8 is a rear elevational view thereof, [0034] FIG. 9 is a right side elevational view of a zipper portion thereof; [0035] FIG. 10 is a left side elevational view thereof, and, [0036] FIG. 11 is a rear elevational view of the other hand of the other embodiment in FIGS. 5-10 for one hand of a pair of zipper-attached front palm units according to the present invention. [0037] The stippling in the drawings represents texture. DETAILED DESCRIPTION OF THE INVENTION [0038] The present invention provides a hockey glove, lacrosse glove, sports gloves, with an easily replaceable front palm-finger unit while protecting the attachment means. [0039] The hockey glove 10 includes a back member 12 having a body portion 14 , a thumb portion 16 and a plurality of finger portions 18 . Padding members 60 are permanently internally encapsulated within the glove to protect the fingers, thumb, back and side portions of the glove and the cuff area 70 , thereby protecting the user's hand. A plurality of internal changeable front member units 40 is provided with each front member including a front palm portion, a thumb portion and a plurality of finger portions. The number of finger portions of the front member unit 40 corresponds to the number of finger portions in a corresponding back member in the preferred embodiment. There can also be a different number of finger elements or socket or receptacle from one to five, however, the preferred would match as stated. [0040] An attaching means removably couples one of the front members to the back member. [0041] The coupled front and back members cooperate to form a hand receiving portion which includes a palm, thumb stall and a plurality of finger stalls. [0042] The hockey and lacrosse gloves and sports gloves of the present invention include the glove to the users' hand and wrist area. The protective element for the wrist area is known as the cuff 70 and 72 in FIG. 1 . A wrist cuff closure mechanism for securely and easily fastening is provided. [0043] The wrist cuff includes a back portion 72 attached to the glove side and the front portion 70 which is attached to it as a continuation from the glove portion 72 . The wrist cuff is not fully sewn to form a continuously closed cuff around its perimeter. There is an open portion, so the cuff is not permanently closed. It allows the cuff to open and close. The two or more parts of the cuff have hinged action from the sewing or attaching the parts together while not permanently attaching the opposite side to the gloves back portion. The closure mechanism may include VELCRO® hook and loop type fasteners, and snaps or any other workable attachment means. The preferred closure has a VELCRO® hook and loop type fastener on the base of the palm at the wrist area and opposite on the cuff side 71 . These two areas coincide to form the attachment at these locations across the lower region of the palm area that meets it. The cuff only requires one snap 80 , which securely fastens the cuff together so it can't open easily in play. The snap is at the end or toward the end of the open portion, two parts that need to be joined to close the cuff. The snap has a male portion and a female portion, the male and female portion are positioned to meet from the two portions that are needed to close the cuff area. FIG. 1 represents the area for the snap at reference numeral pairs 80 , 74 or 80 , 72 or a location in this area as described. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0044] The hockey or lacrosse glove 10 of the present invention includes a back member 12 , shown in FIG. 1 , which covers the back of the user's hand. The back member includes a body portion 14 , a thumb portion 16 and four finger portions 18 , although it should be noted that the glove may be formed with less than four finger portions 18 . [0045] Padding 60 is encapsulated between the body portion 14 and back portion 12 to protect the exterior side of the back member 12 and it substantially covers the exterior portion of the back member 12 to protect the user's hand. The padding 60 may be in the form of foam inserts into the areas needed to be protected such as the fingers and back of hand and side of hand and cuff area. The padding may also be in the form of a plurality of rolls, some of which extend across the back of the hand, generally on the back of the body portion 14 . Other of the rolls may be positioned longitudinally along the back area of the finger portions 18 . Similarly, another padding roll or insert may be provided which corresponds to the shape of the thumb portion 16 . Thumb portion 16 may also have a plastic insert along with foam padding adding further protecting the thumb. Additionally the padding may be tapered and or have any shape desired. [0046] The removable front palm unit 40 , shown in FIG. 5 , covers the front portion of the players' hand. A plurality of front finger members 44 may be provided for use with a single back member 12 . Each removable front palm units 40 includes a palm portion 42 , a thumb portion 46 and four finger portions 44 . The thumb portion is usually stitched to the remainder of the front palm portion. Fewer finger members 44 may be formed limited only in that the number of finger portions 44 of the front palm unit 40 is intended to correspond with the number of finger members 18 of the back member 12 . The front palm unit can be any thickness desired or any material desired or any combinations of material desired. It is contemplated that a plurality of front palm units with varying thicknesses and or materials can be attached to the same back member 12 . However, it is preferred that the front palm unit 40 have a thickness that allows greater feel by the player. This can be achieved using the desired material and thickness for the particular material. [0047] The size and material provide an effective hockey and lacrosse glove which maintains the appropriate flexibility and control for the player. Front palm unit may terminate at the very bottom of the wrist area. VELCRO® hook and loop type fastener or another closure material or device can be stitched to the base of the front palm unit to aid in the cuff closure. As shown in the accompanying drawings, the back member 12 and front palm unit 40 are attached together by a closure, such as a zipper 20 on the front palm unit and 22 on the glove unit, covered by fly 30 from front to back or fly 32 from back to front or fly 34 which forms in the middle to form a hand receiver portion which includes a thumb stall and a plurality of finger stalls. The zipper and fly extend around each finger and thumb unit and side of hand leading toward the cuff on the glove side and each finger and thumb and side of hand leading to the cuff on the palm side. Additionally the zipper and fly cover extend along the thumb 16 on the glove portion and 46 on the palm unit and finger portions 18 on the glove portion and 44 of the front palm unit, thereby connecting the front palm unit to the back member 14 forming a hand receiving unit. The zipper is preferably a thin, narrow, soft zipper with a lock, thereby allowing the zipper 20 on the front palm unit and 22 on the glove unit to effectively operate in the space provided between the finger walls and also the fly cover. [0048] The hockey and lacrosse glove or sports glove 10 of the present invention includes a wrist closure mechanism for securely fastening the glove at the users' wrist. The wrist closure mechanism includes a first flap 70 attached, to one side of the of the body portion 14 . A hook and loop type fastener such as VELCRO®, is attached to the interior of flap 70 at or near the inside horizontal area at 71 . Additionally a snap 80 or other closure devise is attached to the flap 70 . The female portion of the snap can be on the inside of this flap. [0049] A second flap 72 can have the male portion which coincides with the snap on flap 70 . The preferred embodiment would have the male portion on the glove side next to the base of the zipper 74 attachment on the side of the glove. Near this area on the glove side can have the male portion of the snap. This may also be reversed to allow 72 or 74 to have the male side of the snap and the inside of flap 70 have the female portion to receive. The preferred embodiment would have the female portion of the snap on the 70 flap and the male portion of the snap on position 74 . The exterior side of the front palm unit base would also have VELCRO® hook and loop type fastener which coincides to the shape and size on the first flap at 71 for closure purpose. The snap or other closure devise is for a secure closure. [0050] In operation the wrist closure operates as follows: [0051] With or without the players hand in the glove 10 , the first flap 70 secures the VELCRO® hook and loop fastener on the inside of flap 70 coinciding with to the palm units VELCRO® hook and loop fastener type of attachment at coinciding areas or points as it closes and the snap 80 locks the cuff unit secure on position 74 . [0052] The zipper 20 on the palm unit and 22 on the glove portion is protected by the fly cover 30 which goes from front to back, or 32 which goes from back to front or 34 which goes in both direction toward the middle, allows for quick and easy replacement of the front palm unit 40 . The fly cover can be a combination of any direction from the palm unit or the glove portion or be any combination of the two. It can even be different ways of covering the zipper in different sections of the glove or palm unit. The zipper is in a position and protected by the fly cover so that it does not interfere with the operation and use of the hockey or lacrosse glove or other sports glove 10 . The zipper and fly cover extend around the portions of the players hand and fingers in which the hand fits into. The present invention allows a single back member 12 and a plurality of front palm units 40 , thereby extending the life and usefulness and function of the glove 10 . [0053] Another embodiment may have a gap between the base of the palm unit and cuff area. On this glove the cuff will not overlap the palm unit. There can be a gap between the cuff and the palm unit. The tab on the bottom of the zipper on each side may be covered by a piece of material coming off the glove or as part of the replaceable palm or a combination of both. [0054] This embodiment allows more freedom for the wrist to maneuver while having a replaceable palm unit. [0055] Another embodiment is a replaceable front palm unit 40 which has a zipper attachment 20 as shown in FIG. 2 and a fly cover 30 , 32 , 34 as shown in FIGS. 2 , 3 and 4 . The fly cover may be only a portion of a fly cover to cover the zipper attachment or cover a portion of the zipper attachment on the front palm unit. The fly cover may be able to cover the majority or even most of the zipper if not all of the zipper attachment on the front palm unit. Whatever percentage is needed or works best would be alright as the desired results are achieved. The front palm unit has a palm section, a thumb section and a plurality of finger portions which will coincide with the glove portion to form a hand receiving unit. The base of the front palm unit may have VELCRO® hook and loop type fastener to aid in the cuff closure when the palm of the glove is in the glove unit. There may be any number of finger portions or hand shapes—makeup to any desired form to form a hand receiving unit. The fly cover may be any portion of the total fly cover and can vary in thickness and shape or size or length if desired or be consistent if desired or any combination of percentages within the replaceable palm unit. [0056] On the preferred embodiment, the snap would be on the cuff flap 70 with the female portion being exposed on the inside of the cuff flap toward the end of the flap as shown on FIG. 1 . The base of the side of the glove side opposite the cuff flap would have the male portion of the snap 74 as shown in FIG. 1 . This would be next to the palm units' zipper attachment's zipper. The snap could then be closed and secured from the wrist cuff flap to the glove side. [0057] FIG. 2 is a detailed close up view of the glove portion containing a portion of the zipper 20 from the palm unit and 22 from the glove unit. Fly cover 30 on the front palm unit covers both elements of the zipper attachments from the front palm unit and the glove unit. The fly cover is attached to the front palm unit and is made with material that is sewn and part of the front palm unit, thereby protecting the zipper attachment. The direction of the fly cover is from front palm unit towards glove unit. [0058] FIG. 3 is a close up view of an alternative embodiment. On this embodiment the fly cover 32 is part of the glove unit. The zipper 20 from the front palm unit attaches to the zipper 22 on the glove unit the fly cover 32 covers the zipper attachment as shown and describes with material that is attached to the glove unit. This protects the zipper attachment. [0059] FIG. 4 is a close up view of a further embodiment. This shows the zipper 20 from the palm unit joins zipper 22 from the glove unit. The fly cover 34 has material from both the palm unit and the glove unit. The fly cover covers the zipper attachment and protects the zipper. [0060] Another embodiment can have any combination of the above embodiments where the material used for the fly cover can come from either or both the front palm unit or glove unit or both. There can be another embodiment that has varying areas around or near the zipper portion were the material can come from one side or the other or both. [0061] FIG. 5 is a front perspective of a zipper attached front palm unit 40 according to the present invention. This view shows the majority of the zipper element 20 as it goes from the side of the hand closest to the cuff 70 , around the plurality of finger elements 44 and around the thumb area 46 on the front palm unit 42 . [0062] FIG. 6 is a rear perspective view of another embodiment for the zipper attached front palm portion 42 of a pair of front palm and back glove portions 40 and 12 respectively of sports glove 10 according to the present invention. This view shows how the zipper 20 goes from the side of the hand portion closest to the base of the unit continuously up toward and around each finger unit 44 and around the thumb member 46 . [0063] FIG. 7 is a front perspective of a zipper attached front palm unit 42 according to the present invention. This view shows the majority of the zipper element 20 as it goes from the side of the hand closest to the cuff, around the plurality of finger elements 44 and around the thumb member 46 on the front palm unit 40 . [0064] FIG. 8 is a rear elevational view of the front palm unit 42 of this invention. The zipper element 20 goes completely around the palm portion's periphery. [0065] FIG. 9 is a right side elevational view of the palm portion 42 and zipper portion 20 . The length of the zipper 20 is determined by the palm size and dimensions. There is a material component and teeth component to the zipper attachment 20 , which mates with rear zipper attachment 22 shown in FIG. 1 . The material portion gets attached to the palm unit. [0066] FIG. 10 is a left side elevational view of the palm portion 42 and zipper portion 20 . The length of the zipper 20 is determined by the palm size and dimensions. There is a material component and teeth component to the zipper attachment 20 . The material portion gets attached to the palm unit. [0067] FIG. 11 is a rear elevational view of the other hand of the front palm unit 42 of the pair of sports gloves 10 , as in FIGS. 5-10 of this invention. The zipper element 20 goes completely around the palm portion 42 's periphery. [0068] The back glove unit 12 will have the matching portion of the zipper attachment 22 , as shown in FIG. 1 , so the palm unit 40 with palm portion 42 can be joined with the back glove unit 12 to form a hand receiving sports glove unit 10 according to the present invention. [0069] In the foregoing description, certain terms and visual depictions are used to illustrate the preferred embodiment. However, no unnecessary limitations are to be construed by the terms used or illustrations depicted, beyond what is shown in the prior art, since the terms and illustrations are exemplary only, and are not meant to limit the scope of the present invention. [0070] It is further known that other modifications may be made to the present invention, without departing the scope of the invention, as noted in the appended Claims.
A sports glove, such as hockey, lacrosse and other sports gloves, includes a front palm portion having finger stalls for insertion of fingers therein, a back portion which is attachable to said front palm portion by a connector, such as a zipper, wherein the zipper connector is covered by a fly cover having an attachment end and a free end, wherein further lifting of the free end of the fly cover exposes the zipper for user engagement therewith.
0
CROSS REFERENCE TO RELATED APPLICATION This application is a continuation in part of U.S. patent application Ser. No 11/099,404 which was filed on Apr. 5, 2005, now abandoned. BACKGROUND OF THE INVENTION This invention relates generally to the field of renewable fuel productions and more specifically to a process for the production of ethanol by use of a vacuum process and selectively permeable membranes to increase ethanol production efficiency. Production of ethanol is an age old technology that has lacked development throughout the centuries. In both traditional ethanol production (wine making, etc) and commercial ethanol production yeast, a facultative anaerobe, is placed in a solution of sugar or fermenting mash that is open in some way to oxygen. The yeast is allowed to ferment the sugars (glucose) into ethanol until the concentration of ethanol to fermenting mash reaches approximately 15%, at which, the enzyme in the yeast that converts sugar to ethanol is destroyed or denatured due to the high concentration of ethanol and hence ceasing ethanol production. Ethanol production is both more time consuming and only partially efficient. To overcome some obstacles in ethanol production, such as random strains of bacteria ruining the ethanol production process, traditional and commercial ethanol producers sanitize all the equipment used in ethanol production in some way (usually through the use of an iodine solution) to ensure that ethanol and not vinegar will be produced. This has helped to improve the efficiency of ethanol production. Ethanol production ceases once the concentration of ethanol to fermenting mash reaches approximately 15%. To overcome this barrier, some producers have experimented with different strains of yeast or genetically altered yeast to produce high tolerance yeast that can continue to produce ethanol until the concentration of ethanol to fermenting mash reaches approximately 18% to 20%. Basically, the yeast that produces ethanol has a higher tolerance to ethanol concentrations and will not denature until a concentration of approximately 18% to 20% has been reached but this form of improvement (yeast being tolerant to ethanol) is limited. Deficiencies in prior technology include the presence of oxygen in the fermenting mash, either at the surface of the mash or dissolved within the mash, and the fact that the yeast is directly exposed to the fermenting mash. When yeast has oxygen available to it, it will go through cellular respiration rather than alcoholic fermentation, hence making ATP (adenosine triphosphate) instead of ethanol. Accordingly, it is desirable to design and develop new methods and systems for increasing the efficiency in the ethanol producing process. SUMMARY OF THE INVENTION An example method and system increases the efficiency of ethanol production by removing oxygen from contact with ethanol producing yeast, and by continuously removing ethanol through a selectively permeable membrane. An example system utilizes a vacuum process to eliminate oxygen in the fermenting mash to ensure that fermenting mash is not exposed to oxygen during fermentation. This provides for the constant production of ethanol because the yeast is a facultative anaerobe. By eliminating all forms of oxygen, the yeast is forced to constantly go through alcoholic fermentation, hence constantly producing ethanol. This allows the efficiency rate of ethanol production to be greatly improved. A selectively permeable membrane is utilized to maintain a maximum concentration of ethanol with basic yeast of approximately 15% and with genetically engineered yeast of approximately 18-20%. The yeast is suspended within the selectively permeable membrane such that the ethanol and perhaps small amounts of the fermenting yeast pass through the membrane while keeping the yeast inside the membrane with a fresh supply of fermenting mash (glucose solution). This allows the concentration of ethanol to fermenting mash to stay below 15% and allow for constant ethanol production without denaturing the yeast. Accordingly, an example system and method provides for improved efficiency in the production of ethanol. These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of an example device for producing ethanol. FIG. 2 is an enlarged schematic view of an example tube of the example device. FIG. 3 is another enlarged schematic view of an example tube of the example device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 , an example ethanol producing device 10 includes a fermenting chamber 12 that is void of oxygen and filled with a non-oxygen containing gas. Air within the fermenting chamber 12 is removed through a vacuum line 16 and Nitrogen gas (N2) 30 is fed into the fermenting chamber 12 through a hose 20 . A bundle 14 of tubes 32 is disposed within the fermenting chamber 12 . Each of the tubes 32 are fabricated from a selectively permeable membrane that allows ethanol 24 to migrate through the tubes 14 and into the fermenting chamber 12 where it is exhausted through the outlet 22 . The example process for the production of ethanol utilizes a pressure differential between a pressure P 1 within the tubes 32 , and a pressure P 2 within the fermentation chamber 12 to draw ethanol 24 through the selectively permeable membrane of the tubes 32 and into the fermentation chamber 12 . The example process includes the initial step of introducing a biologically pure yeast culture into each of the tubes 14 . The fermentation chamber 12 is sealed from ambient air and oxygen and is filled with a non-oxygen containing gas such as for example Nitrogen 30 . Because the fermentation chamber 12 is substantially void of oxygen, the yeast culture maintains alcoholic fermentation of the glucose solution 28 . In the presence of oxygen, the yeast culture will undergo a cellular respiration and produces ATP (adenosine triphosphate) instead of the desired ethanol. The fermentation chamber can begin with a non-oxygen containing gas such as Nitrogen 30 . Alternatively, a vacuum applied through the vacuum hose 16 can first remove any oxygen or air to provide for replacement with the desired non-oxygen containing gas. Oxygen removal is accomplished with a vacuum pumping system as is known. Other methods of removing oxygen from the fermentation chamber 12 in preparation for filling with a non-oxygen containing gas are also within the contemplation of this invention. Once the fermentation chamber 12 is devoid of substantially all oxygen, the glucose solution 28 is fed into the bundle 14 of tubes 32 . Each of the tubes 32 includes a desired amount of yeast that goes through an alcoholic fermentation in combination with the introduced glucose solution 28 . The non-oxygen atmosphere within the fermentation chamber 12 ensures that the yeast and glucose solution will undergo alcoholic fermentation to produce ethanol. The glucose solution 28 is fed into the tubes 32 within the fermentation chamber 12 at a rate determined to provide a desired production of ethanol. The fermentation chamber 12 includes the inlet 18 for the glucose solution 28 and the outlet 22 for the ethanol 24 produced. The tubes 32 are made from a selectively permeable membrane that provides for the evacuation of ethanol, while maintaining the yeast and glucose solution within the tubes 14 . Referring to FIGS. 2 and 3 , the tube 32 includes a wall fabricated of a selectively permeable membrane 34 . The selectively permeable membrane 34 if of material compatible with the environment within the fabrication chamber 12 . Further, the selectively permeable membrane 34 is of a defined porosity that allows Ethanol to pass through, but that does not allow other elements such as the yeast 40 to pass through. The porosity is a function of the open area that allows ethanol evacuation for a give area. The example tube 32 includes a number of pores 35 ( FIG. 3 ) disposed over the surface area of the tube 32 . The number and size of pores 35 are determined based on the size of the specific yeast utilized in fermentation process. The permeable membrane 34 prevents the evacuation of the yeasts 40 and glucose solutions 28 to maintain the desired production of ethanol 24 . Selectively permeable membranes are known devices and are available for allowing desired content and elements through while retaining the desired elements and compounds within the chamber. Referring back to FIG. 1 , with continued reference to FIGS. 2 and 3 , during the alcoholic fermentation process, the inside of the tube 32 begins to become filled with ethanol 24 . A desired percentage of ethanol 24 within the tube relative to the amount of yeast 40 is controlled by controlling the flow of ethanol 24 through the selectively permeable membrane 34 . The flow of ethanol through the selectively permeable membrane 34 is controlled by controlling a pressure differential between P 1 and P 2 across the permeable membrane 34 . Control of the pressure differential across the permeable membrane 34 along with the specific porosity of the permeable membrane 34 relative to the yeast 40 and glucose solution 28 utilized for the example process provide for a substantially continuous process where glucose 28 is fed in and ethanol 24 is forced through the selectively permeable membrane 34 . Accordingly, the desired flow of ethanol from the plurality of tubes 14 is controlled and continuous. The percent of ethanol 24 to yeast 40 is maintained at a rate determined to not cause the denaturing of the yeast 40 . As appreciated, yeasts of different purities perform most efficiently ad different ethanol concentrations. For example, alcoholic fermentation for normal yeasts begins to degrade as the ethanol concentration approaches 15% relative to the amount of yeasts. Some genetically engineered yeast provides efficient ethanol production up approaching 18-20% ethanol relative to the amount of yeast contained within the process chamber. The system and method of this invention maintains the desired ratio of yeast to ethanol by evacuating ethanol through the selectively permeable membrane 34 . Accordingly, the process can continue for as long as glucose solution is fed into the bundle of tubes 14 . The yeast 40 is suspended within the tubes 14 of the fermentation chamber 12 and does not move through the selectively permeable membrane 34 . The selectively permeable membrane 34 is selected from commercially available devices according to the specific yeast and glucose utilized for the fermentation process. A worked skilled in the art would understand that selectively permeable membranes of differing capabilities can be utilized for different conditions created by different yeast types and glucose types. Further, as the selectively permeable membrane 34 allows ethanol 24 to pass therethrough, and not a substantial portion of the other contents within the tube 32 , the selectively permeable membrane 34 selected will always provide for a desired amount of ethanol 24 to diffuse therethrough responsive to a pressure differential determined to provide the driving force for exhausting a desired amount of ethanol from the tube 32 that would provide a desired balance within each of the tubes 32 . A fresh supply of glucose solution 28 , also known in the art as “fermenting mash” is continually introduced into the tubes 32 as required to maintain the desired rate of ethanol production that corresponds to the desired concentration of ethanol within the fermentation chamber 12 . The glucose solution 28 flows through the tube 32 in contact with the yeast 40 . Circulation of the glucose solution 28 provides for reuse of the solution to efficiently utilize any glucose that did not undergo the fermentation process. While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modification, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
A process for the production of ethanol utilizes a vacuum process and selectively permeable membranes to increase ethanol production efficiency. Yeast converts sugars to ethanol in an anaerobic condition within process chamber void of oxygen and filled with a Nitrogen gas (N2) or any non-oxygen containing gas. A glucose solution is fed into the process chamber to a yeast solution to ferment. A selectively permeable membrane filters ethanol away from the yeast and out of the process chamber. The removal of ethanol from the process chamber keeps the yeast alive to constantly produce ethanol.
2
BACKGROUND OF THE INVENTION This invention relates to a circular braiding machine which comprises an axis of rotation, a group each of inner and outer spools arranged on a circular track coaxial with the axis of rotation and each carrying a strand, drive means for moving the groups of spools in opposite directions, strand guide members for guiding at least the strands of one of the groups of spools at a location between the latter and a braiding point, and means with levers operating synchronously with the drive means and being coupled to the strand guide members for crossing the strands of the inner and outer spools. Braiding machines are known in two main kinds. In one kind, predominantly used in the past, the spool carriers themselves execute their movement in crossing paths needed for the interlacing or cross-overs of the threads or strands (maypole principle). However, the other kind is used predomiantly today, in which the two groups of spools execute circular movements in opposite senses and only the strands of one group are passed alternately over and under the spools of the other group (high-speed braiding principle). The invention is concerned only with the second kind of circular braiding machine as mentioned above. There are various systems for the to and fro movement of the strands. The greatest number of known circular braiding machines operate with swinging levers which are pivotally mounted at one end and have strand guide members at the front end and are moved to and fro with the aid of cranks, eccentrics or control camways (e.g. DE-PS 2 743 893, EP 0 441 604 A1). The strand guide members then perform a substantially sinusoidal movement. This results in a whip-like to and fro swinging of the swinging lever at high speeds of rotation of the circulating spool groups, which leads to high bending stresses and thus to overswing of the swinging lever at the points of reversal and is problematic for constructional reasons (e.g. high wear). Moreover the sinusoidal course of movement has the result that the number of spools which can be fitted round the circumference of the machine has to be comparatively smaller or the spacing between the spools has to be made comparatively greater, if instead of a simple "1 over-1 under" crossing (or braid configuration) a higher order such as a "2 over-2 under", "3 over-3 under" braid configuration or the like is to be provided, because sinusoidal curves run comparatively flat in the crossover region. This disadvantage can it is true be avoided in part if the swinging movement of the swinging lever is accelerated in the crossover regions and retarded in the regions of reversal compared with a pure sinusoidal movement (DE 3 937 334 A1), with the aid of a drive linkage coupled to a crank arm. The whip effect and the constructional problems associated therewith can however only be reduced to a small extent by this. In order to avoid the whip effect it is already known to arrange the strand guide member at one end of a constantly rotating crank slide linkage and so to control the circulating movement of the crank slide linkage that the strand guide member describes the path of a coiled epicycloid (DE 4 009 494 A1). The result of this is that the crank slide linkage with the strand guide member has the greatest angular velocity in the crossover operation but only moves very slowly or is held nearly stationary in between two crossovers, in order to be able also to carry out braid configurations of "2 over-2 under" in this way. However in this solution also the course of the curve in the crossover region is in part relatively flat, so that the spool spacing has to be comparatively large and "2 over-2 under" patterns and higher value patterns cannot be carried out sufficiently economically. Apart from this there is the danger that the individual strands twist up or twist together, especially when the strands are treated, sticky material. SUMMARY OF THE INVENTION In the light of this it is one important object of this invention to so design the circular braiding machine of the kind initially referred to that whip-like movements of the parts moving the strand guide members are largely avoided. A further object of this invention is to design the braiding machine such that comparatively small spool spacings can be realised even if whip-like movements are largely avoided. Yet another object of the invention is to make possible braid patterns up to "3 over-3 under" or even higher value patterns under economic conditions. These and other objects of the invention are solved by a braiding machine which is characterized in that the strand guide members are mounted to reciprocate in guide tracks arranged substantially radially relative to the axis of rotation, and in that the levers are arranged substantially in the extension of the guide tracks and are articulated in the manner of connecting rods at one end to the strand guide members and at the other end to respective rotating crank levers. Further advantageous features of the invention appear from the dependent claims. BRIEF DESCRIPTION OF DRAWING The invention will be explained in more detail below in conjunction with the accompanying drawings of non-limiting embodiments, in which: FIG. 1 is a partailly broken away front view of a circular braiding machine according to the invention; FIG. 2 is a vertical section approximately along the line II--II in FIG. 1 through the upper half of the circular braiding machine, to a larger scale; FIG. 2a is a section according to FIG. 2 through a further embodiment of the braiding machine; FIG. 3 is front view of a guide track of the circular braiding machine, greatly enlarged, as seen from the right in FIG. 2; FIG. 4 is a section along the line IV--IV of FIG. 3; FIG. 5 is a vertical section similar to that of FIG. 2 through a first embodiment, shown to a larger scale of a drive unit of the circular braiding machine according to FIGS. 1 and 2, for driving a strand guide member; FIG. 6 is a plan view of the drive unit according to FIG. 5; FIG. 7 is a view of a lever driven by the drive unit according to FIGS. 5 and 6 in the direction of an arrow x in FIG. 6; FIGS. 8A, 8B, 8C, 8D, 8E show various positions of the lever according to FIG. 7 schematically, during the operation of the circular braiding machine according to FIGS. 1 and 2; FIG. 9 is a schematic representation of the path which is traversed by the strand guide member driven by the lever according to FIG. 7 in the operation of the circular braiding machine according to FIGS. 1 and 2; FIG. 10 is a vertical section similar to that of FIG. 2 through a second embodiment shown to a larger scale of a drive unit of the circular braiding machine according to FIGS. 1 and 2, for driving a strand guide member, along the line X--X in FIG. 12; FIG. 11 is a section through the drive unit according to FIG. 10 along the line XI--XI in FIG. 12; FIG. 12 is a plan view of the drive unit according to FIGS. 10 and 11; FIG. 13 is a view of a lever driven by the drive unit according to FIGS. 8 to 10 in the direction of an arrow y in FIG. 12; FIG. 14 is a schematic representation of the path of movement of the lever according to FIG. 13 in the operation of the circular braiding machine according to FIGS. 1 and 2; and FIGS. 15 and 16 are schematic views of the paths for the strand guide member which can be obtained with different designs of the drive unit according to FIGS. 10 to 12 in operation of the circular braiding machine according to FIGS. 1 and 2. DESCRIPTION OF PREFERRED EMBODIMENTS FIGS. 1 and 2 show a circular braiding machine as an example with a horizontally arranged axis of rotation 1 (FIG. 2). A rotor support 3 (FIG. 2) is fixed on a base frame 2 and a hub 5 is mounted thereon, rotatable about the axis of rotation 1, by means of bearing units 4. The hub 5 carries an annular, substantially circular and vertically arranged rotor 6. A plurality of bearing units 7 are fitted in this at a constant radial distance from the axis of rotation 1 and distributed at equal angular spacings about the axis of rotation, shafts 8 being rotatably mounted parallel to the axis of rotation 1 in these bearing units. A pinion 9 and then a gearwheel 10 are mounted axially behind one another on the front ends of these shafts 8. Each pinion 9 meshes with a stationary gearwheel 11 which is arranged in front of the rotor 6, coaxial with the axis of rotation 1. On rotation of the rotor 6, the pinion 9 rolls like a planetary gear on the gearwheel 11 acting as a sun gear. The rotor 6 further carries a support 12 which is likewise substantially annular and circular, is additionally mounted rotatably on the rotor support 3 by means of bearing units 14 on the inside and is fixed on the rotor 6 in front of the gearwheel 10 by means of pins 13 lying radially outside the shafts 8 and parallel thereto. The support 12 further supports the front ends of the shafts 8 by means of further bearing units 15. In between the rotor 6 and the support 12 intermediate pinions 17 are mounted rotatably on the pins 13 by means of bearing units 16 and are in mesh with the gearwheels 10. As FIG. 1 in particular shows, there are twelve shafts 8 with pinions 9 and gearwheels 10 in the embodiment, arranged about the axis of rotation 1, while two intermediate pinions 17 are associated with each gearwheel 10 with their pins 13 lying on a circle coaxial with the axis of rotation 1. Uniformly spaced segments 18 are fixed on the outer periphery of the support 12 and roller tracks, e.g. of groove form, are formed therein, being open radially outwardly, i.e. upwardly in FIG. 2. Corresponding segments 20 are fixed on the rotor 6 by means of spaced support brackets 21 and roller tracks, e.g. likewise of groove form, are formed therein, being open radially inwardly, i.e. downwardly in FIG. 2. Moreover the segments 20 are arranged axially in front of the segments 18 and at greater radial spacings from the axis of rotation 1 than the segments 18. The roller tracks of the segments 18, 20 serve to receive rollers 23 and 24 respectively, which are mounted rotatably on bearing pins 25 and 26 respectively with axes parallel to the axis of rotation 1. These pins 25, 26 are fixed to spool carriers 27, which like the segments 18, 20 are distributed at uniform intervals around the axis of rotation 1. In addition, ring sections 28 with internal teeth 29 (FIG. 1) are fixed on the pins 25 and mesh with the intermediate pinions 17. The ring sections 28, considered in the circumferential direction of the rotor 6, have such a length that each ring section 28 is always in engagement with at least one of the intermediate pinions 17 during rotation relative to the rotor 6, independent of its instantaneous position, while there is nevertheless radial free space or slots between the individual ring sections 28. The rollers 23, 24 are correspondingly so fitted on the spool carriers 27 that each spool carrier 27 is always guided positively in each segment 18, 20 by at least two rollers 23, 24 during rotation relative to the rotor 6, independently of its instantaneous position, while there are nevertheless slots or radial free spaces between the individual spool carriers. Both the roller tracks of the segments 18, 20 and the teeth 29 lie on circles coaxial with the axis of rotation 1. The spool carriers 27 carry a first group of front or inner spools 31, from each which a thread (wire) or strand 32 is guided to a braiding point 35 over a roller 34 controlled by a tension regulator 33; at the braiding point the braided material 36 is braided as it is transported in the direction of the axis of rotation 1 (arrow v in FIG. 2). Further threads or strands 37 are fed from a second group of rear or outer spools 38, which are fixed by holders 39 on the brackets 21 and are also fed to the braiding point 35 over rollers 41 controlled by tension regulators 40. In accordance with FIG. 1 there are as an example twelve each of the front and rear spools 31 and 38 respectively. The drive of the circular braiding machine is effected by a drive motor 42 mounted in the base frame 2 and driving a drive pinion 44 through gearing 43, the pinion meshing with a gearwheel 45 fixed on the hub 5. Switching on the drive motor 42 results in the hub 5 and the rotor 6, the support 12, the segments 18 and 20 and the rear spools 38 rotating in a selected direction, e.g. clockwise, as is indicated in FIG. 1 by an arrow r. The pinions 9 roll on the periphery of the gearwheel 11 so that both these and also the gearwheels 10 are turned clockwise. As against this the intermediate pinions are driven anticlockwise. By suitably dimensioning the various gearwheels or pinions the rotation of the intermediate pinions 17 is effected at such a high speed that the teeth 29 in engagement therewith and the spool carriers 27 and the spools 31 are moved in the roller tracks of the segments 18, 20 in the anticlockwise direction (arrow s in FIG. 1), moreover with the same angular speed as the rotor 6 but in the opposite sense. In order to wind on the braided material 36 in the manner characteristic of the braiding, with crossing strands 32, 37, the strands of one group of spools must be moved to and fro periodically between the spools of the other group. As a rule it is the strands 37 of the rear spools 38 which are moved through between the front spools 31, for which slots or free spaces of adequate size have to be present at least during the crossover movement not only between the front spools 31 but also between the parts supporting them, these slots or free spaces being provided in the embodiment for example between the segments 18, 20 and spool carriers 27 and also between the brackets 21 or in the rotor 6 and possibly in the support 12. Circular braiding machines of this kind are generally known to the man skilled in the art and do not therefore need to be explained in more detail. As a precaution, reference is made to the publications cited initially, their content hereby being made part of the present disclosure. In the embodiment the strands 37 of the rear spools 38 are periodically moved through between the front spools 31. To this end the strand 37 from each spool 38 is fed firstly over a deflecting roller 47 and thence through a strand guide member 48, for example an eye, to the braiding point 35 and the strand guide member 48 is guided according to FIG. 2 on a curved guide track 49, but equally on a linear guide track, and is reciprocated by a respective lever 50 which is driven from a drive unit 51. A curved guide track 49 makes it possible to keep the distance from the strand guide member 48 to the braiding point 35 substantially constant over its whole path of movement. It is essential in this that each lever 50 is arranged substantially in the extension of the guide track 49 at the two points or reversal of the associated strand guide member 48, i.e. when this reaches the ends of the guide track 49. This is shown in FIG. 2 for the position of the lever 50 shown in full lines. The lever 50 will thus always be stressed in tension or compression, but not by a bending stress, at the points of reversal, so that even at high working speeds, no significant overshoots or vibrations can arise, such as are unavoidable with known circular braiding machines on account of the whip effect. The lever 50 is preferably further so moved that it always makes an acute angle, substantially different from 90°, with the guide track 49 or the current tangent thereto in all position of the strand guide member 48, i.e. in the intermediate positions also it is subjected to bending stresses only slightly. Finally the end of the lever 50 remote from the strand guide member 48 is also at no time reciprocated abruptly but in accordance with FIG. 2 is guided by means of a crank lever 42 round a circular path 53 (arrow w), so that mechanical stresses of the whole strand guide system are largely avoided, even at high working speeds. All these advantages are obtained without it being necessary to move the strand guide member 48 itself on a circulating path, so that twisting of the individual strands is not possible. Each guide track 49 is, as shown by FIGS. 1 and 2, arranged substantially radially and preferably at such an acute angle to the axis of rotation 1 that the spacing of the strand guide member 48 from the braiding point 35 only alters slightly during the to and fro movement along the guide track 49. The guide track 49 advantageously comprises, according to FIGS. 3 and 4, two substantially U-shaped rails 54, whose open sides face each other, with a spacing therebetween, and between which a sliding fit carriage 55 is movably guided with the aid of rollers or the like. This has the strand guide member 48 at its front end, formed e.g. as an eye and so arranged that the strand 37 from the associated spool 38 (FIG. 2) is fed in the arrowed direction (FIG. 3) between the two rails 54 to the braiding point 35, without coming into contact with the rails 54 or other parts of the guide track 49 during the to and fro movement of the carriage 55. At the rear end the carriage is articulated to the lever 50 (cf. also FIG. 2) by means of a bearing unit 56, the lever lying substantially in a conceptual rearward extension of the path of movement formed by the two rails 54, at least at the two points of reversal of the carriage 55 on the guide track 49. FIG. 2a shows a shows guide tracks 49a that are in a linear form. The drive unit 51 can be implemented in various ways and is so designed in an advantageous development of the invention that the speed of the strand guide member 48 at the ends of the guide track 49 is smaller and in the middle part of the guide track 49 is greater than that which would be the case with a pure sinusoidal movement. FIGS. 5 to 9 show an embodiment of the invention using a special eccentric drive unit as the drive unit 51 according to FIG. 2. Each drive unit 51 includes a drive unit housing 57 (FIGS. 5, 6), which is screwed on to the rotor 6 and receives a drive gearwheel 58 which is also shown in FIG. 2 and is fixed on the end of the respective shaft 8 remote from the support 12. The drive gearwheel 58 drives a shaft 60 through a gearwheel 59 fixed thereon, the shaft being mounted rotatably in the drive unit housing 57 by bearing units 61 and carrying a bevel gear at its end remote from the gearwheel 59. The bevel gear 62 meshes with a bevel gear 63, which is fixed by a key 64 (FIG. 6) on a shaft 65 rotatably mounted in the drive unit housing 57. A further gearwheel 66 is fixed on the shaft 65 by the same key 64, on the end remote from the bevel gear 63, and meshes with an intermediate gearwheel 67, which is on a shaft 68 spaced from and parallel to the shaft 65 and mounted rotatably in the drive unit housing 57 and is for its part in mesh with a gearwheel 69, which is fixed on a further shaft 70, which is mounted in the drive unit housing 57 spaced from and parallel to the shaft 65. This shaft 70 carries a second gearwheel 71, which meshes with a gearwheel 72 which is mounted rotatably on the shaft 65 on the side of the gearwheel 66 remote from the bevel gear 63. The gearwheels 66, 67, 69, 71 and 72 are preferably spur gears, bearing units 73 to 77 being provided to support them and journal them stably. A circular disc 78 is fixed on an end of the shaft 65 remote from the bevel gear 63 and can be recessed into the gearwheel 72 and is provided with an eccentrically located cam roller 79, which projects axially beyond the circular disc 78 and the gearwheel 72. In corresponding manner a bearing pin 80 with an axially projecting, circular guide head 81 is provided in the gearwheel 72, parallel to the axis of the cam roller 79, spaced therefrom and also eccentrically arranged. A crank lever 82 is mounted on the free face of the gearwheel 72 and of the circular disc 78 and comprises according to FIG. 7 a slot 83 running parallel to its longitudinal axis at its rear end, with a circular opening 84 in its middle section, and a bearing pin 85 at its front end, with a bearing element 86. The crank lever 82 is mounted slidably and rotatably perpendicular to the axis 87 of the shaft 65 with the cam roller 79 projecting into the slot and the guide head 81 into the opening 84. The bearing element 86 is moreover arranged in a corresponding circular receptacle in the lever 50 (FIG. 2), which is thus rotatably mounted on the crank lever 82 and can also be designated a connecting rod. The manner of operation of the drive unit according to FIGS. 5 to 7 is shown schematically in FIG. 8. Since the gearwheels 66 and 69 (FIG. 6) are coupled by an intermediate gearwheel 67, drive imparted from the gearwheel 58 in synchronism with the rotation of the rotor 6 to the bevel gear 63 in anticlockwise sense results in clockwise rotation of the gearwheel 72, i.e. the cam roller 59 and the guide head 81 run in opposite senses of rotation about the axis 87 (FIG. 6). The transmission ratios of the various gearwheels are so selected that the cam roller 79 and the guide head 81 turn oppositely with the ratio 1:1. The position A in FIG. 8 is that position which corresponds to the left dead point of the lever 50 in FIG. 2. It is assumed that the guide head 81 in FIGS. 6 and 7 is arranged in this position fully to the left and the cam roller 79 fully to the right in the slot 83 and that the guide head 81 and the cam roller 79 rotate respectively clockwise about a circular path 88 and anticlockwise about a circular path 89 which has a smaller radius than the circular path 88. After rotation of the cam roller 79 and the guide head 81 through about 45° each (position B), the crank lever 82 has turned through an angle in the clockwise sense which is substantially smaller than 45° and amount to about 25° for example. After a further rotation of the cam roller 79 and the guide head 81 through 45°, the crank lever 82 is in the 90° position (position C), which means that it has turned through substantially more than 45°, e.g. through 65°. In its further course (position D) the crank lever 82 turns again through about 65° in comparison with a 45° rotation of the cam roller 79 and the guide head 81, until after they have rotated through 180° in total (position E), the crank lever 82 also assumes the 180° position, which would correspond in FIG. 4 to the right dead point of the lever 50 or of the corresponding strand guide member 48. Commencing from the position E, the crank lever 82 then turns in the same direction and with corresponding accelerations and retardations through a further 180°, until it assumes the starting position (position A) again. This means that the bearing pin 85, if the crank lever 82 is used in place of the crank lever 52 in FIG. 2, does not pass round the circular path 53 with constant angular velocity, but the lever 50 accelerates in between the points of reversal of the guide track 49 substantially faster than in the region of the points of reversal. In this way, not only is the whip effect avoided, but operation altogether less subject to wear is facilitated, even at high speeds of rotation, because of the movement of the crank lever 82 and of the bearing pin 85 take place in one direction only. The path 90 which is followed by the strand guide member 48 (FIG. 4) during rotation of the rotor 6 in the direction of the arrow shown is represented schematically in FIG. 9, the movements of the rear and front spools 38 and 31 respectively being denoted by the arrows r and s. Since twelve of each of the spools 31 and 38 are preferably provided, their angular spacing amounts to 30° in each case. The total stroke of the strand guide member 48 is denoted H. FIG. 9 like FIG. 8 makes it clear that the major part of the stroke H is carried out fully between two spools 31, e.g. between about 10° and 25° (spools XII and I) or between about 40° and 55° (spools I and II). The result of this is that at least in the "2 over-2 under" patterns seen in FIG. 9, comparatively large spools, i.e. spools 31,38 with a large original winding diameter can be used, without risk of the crossing strands coming into undesirable contact with one another or with. parts of the machine and thereby affecting the braiding operation adversely. By choice of the eccentricity of the cam rollers 79 and the guide heads 81 the movements of the strand guide members 48 can be matched to the circumstances of a particular case and be modified relative to a pure sinusoidal movement. A second embodiment according to the invention for the drive unit 51 of FIG. 2 will now be described with reference to FIGS. 10 to 16, where a summing drive unit is used for each drive unit 51 of FIG. 4, instead of eccentric drive units. Each drive unit has a drive unit housing 93 (FIGS. 10, 11), which is screwed on to the rotor 6 and which receives the drive gearwheel 58 (FIG. 11) also shown in FIGS. 4 and 5. The drive gearwheel 58 drives a shaft 95 through a gearwheel 94 fixed thereto and the shaft is mounted rotatably in the drive unit housing 93 by bearing units 96 and carries a bevel gear 97 at its end remote from the gearwheel 94. The bevel gear 97 meshes with a bevel gear 98 which is fixed by a key 99 (FIG. 12) on a shaft 100 rotatably mounted in the drive unit housing 93. A further gearwheel 101 is fixed on the end of the shaft 100 remote from the bevel gear 97 by the same key 99 and meshes with a gearwheel 102 which, together with a further gearwheel 103, is on a shaft 104 spaced from and parallel to the shaft 100. The gearwheel 103 meshes with a gearwheel 105 which is freely rotatably mounted on the shaft 100 on the side of the gearwheel 101 facing away from the bevel gear 98. The gearwheels 101, 102, 103 and 105 are preferably spur gears. The shaft 100 and the gearwheel 105 are mounted rotatably in the drive unit housing 93 by bearing units 106 to 109 for mutual support and stable journalling. According to FIGS. 10 to 12, the shaft 104 is rotatably mounted in an oscillating frame 112 by means of bearing units 110, 111, the frame for its part being rotatably mounted by means of bearing units 114 and 115 on the shaft 100 or axially extending collars of the gearwheels 98, 101 and 105 and being capable of swinging to and fro about an axis 113 (FIGS. 10, 12) of the shaft 100. The oscillating frame 112 is provided with teeth 116 on an outer wall surrounding the shaft 101 in ring manner, the teeth 116 being in engagement with teeth 117 on a rack 118 which can be moved to and fro perpendicular to the axis 113 in a guide 110 fixed in the drive unit housing 93 and in the direction of an arrow z (FIG. 11), in order thereby to turn the oscillating frame 112 and with it the shaft 104 and the gearwheels 102, 103 about the axis 113, without the engagement between the gearwheel pairs 101, 102 and 103, 105 being lost. A rod 120 acting as a connecting rod serves for the to and fro motion of the rack 118, its one end being articulated by means of a pivot pin 121 to one end of the rack 118 and its other end being fitted on an eccentric disc 112 acting as a crank and fixed eccentrically on the end of a shaft 123. The shaft 123 is mounted rotatably in the drive unit housing 93 by means of bearing units 124 and arranged with its axis perpendicular to the axis 113. A gearwheel 125 which meshes with the drive gearwheel 58 if fitted on a part of the shaft 123 remote from the eccentric disc 122. The rear end of a crank lever 126 is fixed to the gearwheel 105 (FIGS. 12 and 13), the crank lever corresponding to the crank lever 82 according to FIGS. 6 and 7 and like that being rotatably connected by means of a bearing pin 127 and a bearing element to the lever 50 according to FIG. 4. The longitudinal axis of the crank lever 126 is correspondingly arranged perpendicular to the axis 113 and rotatable about the same. The manner of operation of the drive unit according to FIGS. 10 to 13 is shown schematically in FIG. 14. Since the gearwheels 101 and 102 on the one hand and 103 and 105 on the other hand are in direct mesh, the gearwheel 105 turns in the same direction as the gearwheel 101 when the latter is driven through the gearwheel 94 from the drive gearwheel 58 in operation of the circular braiding machine. Since however the rack 118 is driven at the same time by the gearwheel 124 and turns the oscillating frame 112 about the axis 113 (FIGS. 10, 12) via the teeth 116, 117, the gearwheel 103 rolls on the periphery of the gearwheel 103, in dependence on the direction of movement of the rack 118 (arrow z in FIG. 11). The gearwheel 105 therefore has superimposed, in addition to the rotational movement imparted by the shaft 100, a second rotational movement in the one or the other direction, so that it turns faster or slower than corresponds to the rotational movement of the shaft 100. The same applies to the rotational movement of the crank lever 126 and the lever 50 connected thereto. All in all, as in the embodiment according to FIGS. 5 to 9, a sinusoidal movement imparted by the shaft 110 therefore has a superimposed second sinusoidal movement imparted by the rack 118, which with suitable dimensioning of the gearwheels involved again results in the strand guide member 48 moving more slowly in the regions of reversal and faster therebetween along the guide track 49 (FIG. 4), than corresponds to a pure sinusoidal movement. This is shown schematically in FIG. 14. By selection of the drive of the rack 118 the movements of the strand guide members 48 can moreover by matched to the particular case and be widely modified relative to pure sinusoidal movements. In FIG. 14 it is assumed that the shaft 100 turns at a constant angular velocity in the direction of an arrow t. After each rotation through about 15°, 30° and 45° the gearwheel 105 (or the crank lever 126) travels overall merely through angles of rotation of α 1 ≈2°, α 2 ≈7.5° and α 3 ≈18° respectively. After rotation of the shaft 100 about a further 45° into the 90° position, the crank lever 126 also assumes the 90° position, so that it has turned substantially more in the second 45° cycle, namely through about 72°. In the next two 45° rotation of the shaft 100 the crank shaft 126 correspondingly moves through angles of firstly 72° and then 18°, so that there is again agreement in the 180° position and the strand guide member 48 assumes the right dead point of the guide track 49 in FIG. 2. With further rotation through 180° the same process takes place until in the 0° position all parts have again assumed the starting position and the strand guide member 48 assumes the left dead point position in FIG. 2. The path 130 which is described by the strand guide member 48 in the direction of the indicated arrow with rotation of the rotor 6 is shown in FIG. 15. This path 130 corresponds largely to the path 90 according to FIG. 9 and thus leads to the same advantages as this. In contrast to FIG. 9 however, the path 130 runs somewhat flatter in the regions of reversal than the path 90. A pure sinusoidal curve is indicated in broken lines as in FIG. 9 for comparison. Depending on the transmission ratios of the gearwheels involved and the drive of the rack 118 it is even possible with the embodiment according to FIGS. 10 to 12 for the gearwheel 105 to run briefly in the opposite direction to the shaft 100, i.e. its angular velocity can become negative. This is indicated schematically in FIG. 16 for a path 131, which is described by the strand guide members 48 in the direction of the indicated arrow. In contrast to FIGS. 9 and 15 the strand guide members 48 here lead in the regions of reversal of the path 130 not only to a retarded movement but even to a reciprocating movement along a wait loop 132 or 133 with a small stroke. This makes it possible for the strand guide members 48 to dwell for a selected dwell time in the regions of reversal before the next crossover operation is effected. An advantage of this measure lies in the dwell time, as FIG. 16 shows, can be made so long that "3 under-3 over" patterns are possible, without the steep curve sections of the track having to be abandoned in the crossover regions. The invention is not limited to the described embodiments, which can be modified in many ways. This applies especially to the means which are used in a particular case to realise the eccentric or summing drive unit or any other equivalent drive unit. It would also be possible to effect the to and fro movement of the strand guide member 48 48 and/or of the oscillating frame 112 with other than the means shown. Also the circular braiding machine described with reference to FIGS. 1 and 2 only represents an example, since the described embodiments for the drive unit could basically be used with suitable modification of the overall construction for all circular braiding machines, including those with a vertical axis, which are provided with reciprocating strand guide members for producing the necessary crossovers. It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above. While the invention has been illustrated and described as embodied in an arrangement with a braiding machine of the high-speed braiding principle, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:
The invention relates to a circular braiding machine with two groups of spools (31, 38) circulating about an axis of rotation (1) on a circular path in opposite directions of rotation, the spools carrying strands (32, 37) for braiding a braided material (36) at a braiding point (35). In order to cross the strands (32, 37) in the manner characteristic of the braid (e.g. "2 over-2 under") there serve strand guide members (48) which are mounted to reciprocate on guide tracks (49) arranged substantially radially relative to the axis of rotation (1), as well as levers (50) which are arranged substantially in the extensions of the guide tracks (49) and are articulated in the manner of connecting rods at one end to the strand guide members (48) and at the other end to rotating crank levers (52).
3
BACKGROUND OF THE INVENTION The invention relates to a folding rigid caravan with assisted erection and, relates more particularly, to methods for mounting its resilient erecting elements. Folding rigid caravans with assisted erection are known. These comprise a base carried by a chassis defined by a floor and four substantially vertical lower panels, namely end panels (front and rear) and side panels (right and left); four upper panels, namely end panels (front and rear) and side panels (right and left), pivotal about horizontal axes at the upper free edge of the lower panels and disposed respectively either substantially horizontally in the upper opening of the base or substantially vertically as extensions of the corresponding lower panels when the caravan is folded or completely erected; and a roof pivotally connected to the upper end panels by means of rollers having axes corresponding to the upper horizontal edges of the upper end panels, cooperating with slideways in the roof which rests horizontally either on the base or on the upper panels when the caravan is folded or completely erected. At least one and generally more unidirectional resilient erecting elements such as jacks, for example pneumatic jacks, are each articulated to the base and an upper panel particularly, an end panel, with a view to urging this panel to pivot permanently in the direction of erection of the caravan. In a first embodiment (French Pat. No. 2,284,480) the erecting elements are disposed permanently and entirely outside the caravan and, at least when it is erected, across the horizontal plane defined by the pivotal axes of the upper side panels, hereinafter called plane P. This arrangement permits the location of the erecting elements with the proper inclination for conferring on them maximum efficiency, but on the other hand they are visible on the exterior of the caravan and are subject to shocks. As a variation (French Pat. No. 2,296,545), the erecting elements are partially located in a casing arranged as an extension of the caravan base with consequent drawbacks. In a second embodiment, the erecting elements are disposed permanently and entirely inside the caravan that is to say the space defined by the base, the upper panels and the roof. Three variations of this construction have been proposed. In the first construction (French Pat. No. 2,355,692), the erecting elements are located permanently and entirely above plane P and are articulated to the base by cranked members of L-form in order not to hinder pivoting of the side panels once the end panels are raised. This construction is thus complex, costly, non-aesthetic (since the erecting elements are located opposite the upper panels) and dangerous since if the upper end panels are not in their correct position, the upper side panels can interfere with the erecting elements. In the second construction, the erecting elements are located across plane P. Thus in order to allow pivoting of these panels, at least one of the pivotal connections of each erection element is removable which has the drawback of being non-aesthetic, poorly designed and not very reliable. In the third construction (French Pat. No. 2,263,907) the erecting elements are located permanently and entirely above plane P. To allow for pivoting, the upper side panels are connected to the base by hinges with offset axes, which has the drawback of being non-aesthetic, costly and unsatisfactory. In the three constructions, a space for the passage of the erecting element is provided between each vertical edge of the upper side panels and the internal face of the adjacent upper end panel. This space is concealed, when the caravan is erected, by a batten securely fixed to the upper end panel on its internal face and along its edge. It is thus equally necessary to provide a housing space for these battens when the caravan is erected. For example, the upper edges of the lower end panels are disposed above those of the lower side panels and the base thus has a non-aesthetic step in the region of its opening, creating problems of weather-tightness and necessitating that the roof be provided with a vertical depending edge forming a cover masking this stepping. This depending edge is equally essential to rigidify the roof due to insufficient seating on the base. This weighting of the roof requires the provision of more powerful erecting elements and creates numerous other problems in manufacture and usage of the caravan. Thus, known constructions of folding rigid caravans with assisted erection are not very satisfactory insofar as the erecting elements are concerned. SUMMARY OF THE INVENTION The invention seeks to obviate these drawbacks and proposes a folding caravan with assisted erection by means of resilient erecting elements in which the resilient erecting elements are disposed not outside or, properly speaking, inside the caravan but in housings or grooves provided for this purpose within the thickness of the panels of the caravan and concealed both from the exterior and the interior, that is, each erecting element in the erected position is within a space defined by an upper horizontal edge of a lower panel, a side edge of the upper panel perpendicular to the lower panel, and the two faces of the upper panel parallel to the lower panel. BRIEF DESCRIPTION OF THE INVENTION The other features of the invention will be understood by virtue of the ensuing description referring to the accompanying drawings in which: FIGS. 1A and 1B are two partial half-views of the caravan folded and erected, respectively; FIG. 2 is a cross-sectional view to an enlarged scale along line II--II in FIG. 1B; FIG. 3 is a cross-sectional view to an enlarged scale along line III--III in FIG. 1B; FIG. 4 is a cross-sectional view to an enlarged scale along line IV--IV in FIG. 1A; FIG. 5 is a cross-sectional view to an enlarged scale along line V--V in FIG. 2; FIG. 6 is a schematic view showing a variation of the control means for the erection of the caravan; FIG. 7 is a partial diagrammatic cross-sectional view along a vertical plane on line VII--VII in FIG. 9 along the median line of a caravan according to the invention in an erected condition; FIG. 8 is a schematic view in partial cross-section along a vertical median plane of a caravan according to the invention in a folded condition; FIG. 9 is a schematic cross-sectional view along a horizontal plane including line IX--IX of FIG. 7, the caravan being erected; FIG. 10 is a schematic cross-sectional view along a horizontal plane showing a variation of the caravan shown in FIG. 9; and FIG. 11 is a schematic cross-sectional view along a vertical plane showing a variation of FIG. 7. DETAILED DESCRIPTION OF THE INVENTION The folding rigid caravan with assisted erection according to the invention comprises a base 1, carried by a chassis with towing arrangement and defined by a floor 2, which is normally horizontal, four lower substantially vertical panels--respectively, and panels 3 (front and rear) and side panels 4 (left and right), and four upper panels--respectively, end panels 5 (front and rear) and side panels 6 (left and right) and a movable roof 7 is associated with the upper panels. The base 1, the floor 2, and the panels 3, 4, 5, 6, and the roof 7 are of rigid construction and made out of suitable material such as wood, metal, plastics material etc. Each upper end panel 5 is hinged along its horizontal lower free edge 8a respectively to the upper horizontal free edge 8b of the corresponding lower end panel 3 and is thus pivotally movable about an axis. Each upper side panel 6 is hinged along its lower free edge 6 respectively to the upper horizontal free edge 9b of the lower side panel 4 and is thus pivotally movable about an axis 9. The upper panels 5, 6 are located either substantially vertically and as extensions of the corresponding lower panels 3, 4, or substantially horizontally in the upper opening of the base 1 when the caravan is respectively either fully erected or folded. Each upper panel 5,6 has a thickness, side edges and two faces defining the thickness. The edges 8b, 9b of the lower panels 3 and 4 are coplanar, that is to say the base 1 is level in the region of its opening. In combination and when the caravan is folded, the upper side panels 6 are coplanar and in abutment on the upper end panels 5 which are also coplanar. To this end, the axes 9 are situated at least substantially in the horizontal plane defined by the horizontal free upper edges 8b, 9b and the axes 8 located in a horizontal plane situated at a slightly lower level in such a manner that the spacing between these two planes corresponds to the thickness allowing the location of the upper end panels 5 below the upper side panels 6. In this way, in order to cause the articulation between an upper end panel 5 and a lower end panel 3, one can use an offset axis or the like. The caravan also comprises at least one and, generally several unidirectional resilient erecting elements 10, namely jacks, for example pneumatic jacks, hinged to the base 1 particularly to a lower end panel 3 and to an upper panel, particularly a side panel 6 respectively by spindles 11, 12 which are horizontal and parallel with a view to urging the upper side panel 6 constantly into an erected condition. In particular, two elements 10 for the panel 6 are provided but the invention also applies to a different number of elements 10 and also to different arrangements of the elements 10 and the panels 4 and 5. The elements 10 are not located on the exterior nor strictly speaking on the interior of the caravan, but in an intermediate zone defined by the panels 3, 4, 5, 6 in order to eliminate the drawbacks of known arrangements. To this end, in a first possible arrangement, a housing or groove 13 is located in the upper horizontal edge of each panel particularly the end panel 3 which is hinged to an element 10 with a sufficient depth to allow the element 10 to be placed entirely therein when the caravan is folded. This housing or groove 13 is provided either in the form of a hollowed-out area in the lower panel 3 or preferably by means of a profile of appropriate shape constituting the upper horizontal free edge 8b of the said panel. Several variations of this arrangement are described below. The housing or groove 13 permits the stowing of the element 10 when not in use and allows access thereto in case of need. The spindles 11, 12 are secured respectively to the base 1 and to the upper panels notably 6 by appropriate means in the form of a joint. In order that the element 10 have maximum effect, the spindle 11 is located preferably at the base of the housing or groove 13, that is to say offset towards the base in relation to the plane of the axes 9 and disposed towards the interior of the caravan in the direction of a median vertical plane of symmetry of the latter. Thus, the spindle 11 is transversely offset from the neighbouring axis 9. The spindle 12 is situated on a panel 6 sufficiently offset from the corresponding axis 9. In order to avoid excessive projection of the element 10 from the internal face of the upper side panel 6 at the level of the joint associated with the spindle 12, the spindle 12 is preferably located in a housing 14 hollowed for this purpose in the upper side panel 6 from its interior face. The housing or groove 13 extends along all or only a part of the edge of a lower end panel 3 between the two opposed panels 4. In order to allow movement of the upper end panels 5, it is provided, in known manner, that the spacing between the two normally vertical edges of a panel 5 is smaller than the spacing between the internal faces of the two panels 6. The existing clearance is thus masked externally in a known manner by means of flaps 15 which are provided on the panels 6. These flaps 15 are arranged in coplanar pairs in the plane of the vertical edges of the panels 6 and extend towards the interior of the caravan and are provided in particular by the attachment of angle irons or the like to the panels 6. The clearance is masked on the inside by means of battens 17 or the like rigidly fixed to the panels 6. Each lower corner of an upper end panel 5 is bevelled as at 18 which defines a free space for the passage of the elements 10. The apertures left by these bevels 18 are masked externally by plates 19 having triangular corners which are integral or attached to the flaps 15 and, internally, by similar angle plates 20 fixed to the panels 5. The roof 7 as described above is ssociated with the upper side panels 6 and not with the upper end panels 5, as is known. This is accomplished by means of rollers 21 pivotally mounted on the panels 6 around shafts 22, which are adjacent the upper horizontal edges of the panels cooperating with complementary guide-ways 23 fixed to the depending end edge 24 of the roof 7. This arrangement has the effect that, on the one hand, the increase in bulkiness caused by the rollers 21 and guide-ways 23 is formed at the front and rear ends of the caravan and not along the sides and, on the other hand, the free space inside the caravan can be increased and used efficiently. The lower horizontal edge of the depending side edge 25 bears on the upper edge 9b of the panels 4 (contrary to known arrangements), where support of the roof 7 on the base 1 allows lightening of the roof 7 and the elements 10. Equally, the panels 6 can, when the caravan is folded, be placed to one side and to the other. To this end, the height of the upper panels 5, 6 is at the most equal to half the width of the base 1 measured between the axes 9. The panels 5 are thus no longer load-bearers and can be used for other specific purposes. For example, the panels 5 are able to be designed in order to be folded down along their width in the same manner as a ventilator to enable air to circulate. Naturally, this particular association of the roof 7 with the panels 6 is in no way limiting and the invention applies equally to the case where the roof 7 is associated with the panels 5. FIG. 6 shows a variation of a caravan as described above comprising means for actuating the panels 6 usually in the form of screw jacks 26 placed in the housings or grooves 13 provided with two threads 27 of opposed direction, each of which cooperates with a nut 28 of opposed thread. On each nut 28 is hinged a strut 29 which is hinged at its other end to one panel 6 in particular in the housing 14. The struts 29 can thus be located in the housings or grooves 13 when the caravan is folded. Counterbalancing struts 30, hinged to the panels 6 on the one hand and to the roof 7 on the other hand permit keeping the roof 7 in permanent horizontal equilibrium. By means of a bevel gear 31 and a shaft 32, the two screw jacks 26 can be driven by drive means 33 such as a motor located in the base 1 of the caravan. The housing 13 can be made in various ways as will be described hereafter in the case where the elements 10 are associated with the panels 5 (but which can also be employed in the case of the panels 6). In a first variation (FIGS. 7 and 8) the housing 13 is in the form of a recess or groove, inside a panel 4 and extending from the adjacent panel 3, limited on its two major plane and parallel faces respectively by the inside and the outside faces of the panel 4. The recess is, in elevation, of V-shape or pseudo V-shape wherein a first arm 34 is coplanar with the internal face and inclined to the panel 3 and whereof a second arm 35 is also inclined and is directed upwards towards the middle part of the caravan which is also inclined. The two arms 34 and 35 define at their junction a lower point 36. The free tips 37, 38 of the branches 34 and 35 define the upper opening of the recess, which is the housing 13. This opening is defined sectorially which does not weaken the panel 4 and allows the attachment and the seating of the panel 6 on the upper horizontal edge of this panel 4. The inclination of the arm 35 is such that it allows the housing of the element 10 when the caravan is folded (FIG. 8). The spindle 11 is carried either by the panel 3 or by the panel 4 particularly in the vicinity of the point 36. In this particular arrangement the base 1 presents an upper opening with displacement towards the base at the level of the upper edges of the panels 4, that is to say the upper edges of the panels 4 are located beneath the upper edges of the panels 3 in such a manner that the panels 6 are at least substantially juxtaposed and coplanar under the panels 5 when the caravan is folded. According to another possible variation, there is provided a profile 39 of U-shape of which the core 40 is attached to the internal face of the panel 5. This profile 39 extends from the edge 8a in the direction of the upper horizontal edge opposite the panel 5 and is located in order to lie over the opening of the housing 13 when the caravan is folded (FIG. 8). The spacing between the two flaps 41 of the profile 39 corresponds substantially to the thickness of the panel 4 and the panel 6 with which the profile 39 extends. The element 10 is located at least partially at its upper part in the profile 39 which supports the spindle 12. The free side edges 42 of the flaps 41 are spaced from the vertical edge 43 opposite the panels 6 in a manner such that the profile 39 does not interfere with this panel 6 when in the vertical position. Naturally, within the scope of the invention, other embodiments of the profile 39 can be employed, in particular in the form of two angle members or the like. More generally, the profile 39 is replaced by any appropriate member giving a satisfactory spacing between the two spindles 11, 12 in order to improve the action of the element 10 at the instant of opening of the caravan while permitting housing of the element 10 at least as regards its part outside the housing 13. The free edge of the flap 41 can cover the attached plate 19 to conceal the bevelling 18. The combination of the housing 13 such as described, the bevelling 18, the plate 19 and the profile 39 constitutes a continuous housing--with the caravan folded or wholly erected--formed within the thickness of the caravan wall and in which is disposed the element 10. In another embodiment (FIG. 11) the housing 13 is omitted and the element 10 is pivoted directly to the base 1 or in the region of the upper horizontal edge of the longitudinal lower panel 4. In yet another variation also illustrated in FIG. 11 but applicable to other embodiments already described, the bevelling 18 and possibly the plate 19 are omited which is possible due to the inclination given to the element 10 and the spacing between the vertical edge 43 of the panel 6 and the internal face of the panel 3. In the embodiment of FIG. 10, the housing 13 in the base 1 is totally or partially omitted as indicated above and the element 10 is at least partially disposed in a housing 45 associated with an upper end panel 5. In this embodiment, the panel 5 comprises a core 46 enclosed at its vertical edge 47 by a profile 48 forming a corner of the panel 5. The profile 48, which is made of metal or plastics material, comprises a first U-shaped part 49 with which the core 46 cooperates to ensure a rigid connection between the core 46 and the profile 48, and a second U-shaped part 50, whereof the core 51 is an extension of the exterior flap of U-shaped part 49, this second U-shaped part 50 constituting the ousing 45 and the resilient element 10 being connected by its spindle 12 to the core 51. Similarly to previously described embodiments, the external flap 52 of the second U-shaped part 50 is longer than the internal flap 53. The element 10 is, for example, directly connected to the panel 4 at its upper horizontal edge. The panel 6 is provided on its edge 43 with a profile 54 of inverted U-form with a flap 55 having a function corresponding to that filled by the attached plate 19. In this construction, the flaps 52 and 53 have an identical purpose to that filled by flaps 15 and 41. This particular construction permits either omission of the housing 13 as described, or reducing it, or inclining the element to increase its effect.
A folding, rigid caravan with assisted erection. A base is carried by a chassis defined by a floor and four lower panels, each of which has an upper edge. Two upper end panels and two upper sidewall panels are provided pivotal about the horizontal axes and disposed respectively either substantially horizontally within the upper opening of the base or substantially vertically as extensions of the corresponding lower panel when the caravan is folded or erected. Each upper panel has a thickness, side edges and two faces defining the thickness. A roof rests horizontally either on the base or on the upper panels, respectively, when the caravan is folded or fully erected and is movably associated with the upper panels by rollers engaging in guideways. At least one uni-directional extensible erecting element is provided connected to the base and to an upper panel to urge the upper panel to pivot permanently in a caravan unfolding direction. Each erecting element is disposed permanently at least partly within the thickness of the panels defining the caravan concealed from the outside and inside. Each erecting element in the erecting position is within a space defined by an upper horizontal edge of a lower panel, a side edge of the upper panel perpendicular to the lower panel, and the two faces of the upper panel parallel to the lower panel when the caravan is erected.
1
BACKGROUND OF THE INVENTION The invention relates to a method for traction control (ASR) which will aid initiating movement on an incline. The simultaneous use of ABS (anti-skid braking system) components provided in automobile brake systems for traction control or as an aid in starting movement uphill or on a slippery surface is known from British Pat. No. 2,119,883. The patented device makes use of a special embodiment of an anti-skid system, the so-called ABS-2. This kind of known anti-skid system is provided with pressure fluid tanks combined with a recirculating pump. In the ABS step of pressure reduction, the pressure fluid reservoirs receive pressure fluid from the wheel brake cylinders through the ABS control valves, which are usually of the 3/3-way type, switched accordingly. Via the recirculating pump, which communicates with the reservoir tanks or chambers, the pressure fluid then reaches the connecting line between the master brake cylinder and the wheel cylinders; as related to the standpoint of the master brake cylinder, the connection is typically located upstream of the ABS control valves. To achieve traction control on the basis of this known, separate ABS-2, British Pat. No. 2,119,883 provides an additional pressure tank, which in the event of a traction control function communicates via a 3/2-way valve with the pressure line leading to the wheel brake cylinders. Depending on the triggering of the ABS control valves for the ASR (traction control) function to be achieved, the fluid pressure available in this pressure tank reaches whichever wheel brake cylinder on the driven axle is to be selectively triggered to attain a locking differential effect; in that case, the ABS control valves are triggered inversely, which can be done via a suitably embodied control logic circuit for the combined ABS/ASR situation. For economical yet fully high-quality traction control by using the components of the anti-skid control means, a further pressure controlled reversing valve, an overpressure valve and a pressure switch are provided in addition to the pressure tank and the magnet valve connecting it with the wheel cylinders. The pump is designed as an aspirating pump, and whenever there is not enough pressure in the tank, upon the switchover of the magnet valve, for attaining traction control functions, the pump is triggered either via the pressure switch or directly by the electronic control unit, so that it feeds pressure fluid into the pressure tank or into the brake circuit connected to it. The additionally provided pressure controlled reversing valve opens when a predetermined minimum pressure is attained at the outlet of a feed pump storage chamber, and thus causes pressure fluid to flow from the master brake cylinder to the reservoir chamber and provides for refilling. Finally, the check valve that is also provided assures that the pressure between the magnet valve that switches over when ASR functions are to be performed and the ABS valves do not become excessively high in the vicinity of the wheel brakes. U.S. Pat. No. 4,416,347 also discloses the use of ABS components for traction control or as an uphill movement starting aid, with corresponding "inverse" triggering of the ABS control valves and modification of other existing components, although if both driven wheels are spinning very markedly, additional means are provided, which lower the output power of the driving engine, by exerting influence on the mechanical connection between the gas pedal and the throttle valve in the intake tube of the engine. This can be done with the aid of an electromagnetically triggered 3/2-way valve. In a further combined apparatus for achieving both anti-skid and traction control functions using the same components, the ABS system is assigned an additional pressure tank, which serves to supply braking pressure in the event of traction control functions. This pressure tank can be charged under valve control with the aid of the recirculating pump of the anti-skid system; the recirculating pump feeds into this tank during the pressure reduction phases of the traction control. Outside such control phases, or in other words during normal operation, the pressure tank can be recharged either by actuating the vehicle brake, or, if the vehicle is stopped or is in a non-braked operating state, by automatic activation of a charging circuit with the cooperation of the recirculating pump. Here, precisely as in the combined systems discussed earlier above, additional hardware components are needed--that is, at least one additional pressure tank and hydraulic lines connecting it with the other components--and the required pressure for achieving traction control functions is always drawn from this additional pressure tank. OBJECT AND SUMMARY OF THE INVENTION It is an object of the present invention, based on an anti-skid system of the ABS-2 type, to embody this system with the fewest possible additional means in such a way that, when considering the driver and using appropriate software that can be installed in the control unit (on-board computer) without difficulty, an effective traction control or uphill movement starting aid can be achieved, with a pressure level that is independent of the function of the tank chamber that the ABS-2 system always has. The invention attains its object and has an advantage that even though it dispenses with an additional supply of energy, nevertheless traction control functions can be achieved at very little additional expense by effectively generating braking pressure, in the sense of a locking differential effect, at the wheel that is spinning. The only additional hardware expense required is a reversing valve, preferably in the 3/2-way version; in an advantageous embodiment, two check valves can also be used, one of which is an overpressure check valve. The invention uses the existing basic components of an ABS-2 type of anti-skid system, that is, the existing recirculating pump, and the pressure tank present as an ABS component, though instead of using the possibly limited pressure generated by this tank, in the traction control situation the desired selective braking pressure action is generated by drawing pressure fluid from the tank with a recirculating pump. Another advantage is that the invention expressly includes the driver of the vehicle in the achievement of traction control functions, so that these functions are attainable only when the driver considers them desirable. Both normal braking and the attainment of anti-skid functions in a given situation can be performed unhindered by the expanded possibilities of the traction control functions. Other advantageous features of the invention are disclosed herein. For instance, parallel to the reversing magnet valve, a one-way valve is connected in the direction of the wheel brake, so that even during the performance of traction control functions, while the reversing magnet valve is triggered, the brakes can still be actuated. The invention will be better understood and further objects and advantages thereof will become more apparent from the ensuing detailed description of a preferred embodiment taken in conjunction with the drawing. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 schematically shows a detail of an automobile brake system with the master brake cylinder and some ABS components, as well as several modifications made possible by the invention; and FIG. 2 illustrates a flow chart for a programmed operation of the traction control. DESCRIPTION OF THE PREFERRED EMBODIMENT It should be noted at the outset that the drawing shows only the hardware components necessary for the invention; to trigger the electromagnetic reversing and control valves provided, an electronic control circuit not shown in the drawing, preferably in the form of a program-controlled computer, is provided, which triggers and reverses the switches as necessary on the basis of the output signals supplied to it by well known wheel sensors and possibly other information. Such control circuits are known for standard brake systems including associated ABS components, so these features need no further description here, even in the expanded version for traction control (ASR) operation. In the drawing, the master brake cylinder of the brake system is shown at 10; it includes the brake pedal actuation 11 and a supply tank 12 for the pressure fluid; in the present case, two separate brake circuits I and II are provided, each either leading to the wheels of a different axle, or with diagonal brake circuit layout, each acting on one front and one rear, diagonally opposed wheel. It is assumed that in the exemplary embodiment shown, brake circuit I, which is shown in detail, is connected in its particular layout with the wheel brake cylinders 13a, 13b of the wheels of the driven axle; in a known manner, multi-position magnet valves 15a, 15b (3/3-way valves) that effect the ABS functions of pressure buildup, pressure maintenance and pressure reduction are incorporated into the pressure line from the master brake cylinder 10, between the master cylinder and the wheel brake cylinders 13a, 13b. To receive excess pressure fluid in the ABS function of pressure reduction, the applicable valve connection 16a, 16b communicates with an end chamber 17, which in a cylindrical housing 18 includes a piston 20 biased by a spring 19. To recirculate the pressure fluid received by the tank chamber back into the brake circuit, a recirculation pump 21, RFP for short, communicates via a one-way pump inlet valve 22 with the tank chamber 17 and via a one-way pump outlet valve 23 with the main connecting line 14 between the master brake cylinder 10 and the wheel brake cylinders. In order to achieve a traction control or uphill movement starting aid according to the invention on the basis of this kind of brake system having an ABS-2 type of anti-skid system, the only additional hardware component is a magnetic reversing valve 24, MVU for short (this abbreviation is mentioned here to facilitate interpreting the flow chart that follows later below), installed in the master brake circuit I of the driven axle upstream of the ABS control valves 15a, 15b. The reversing magnet valve 24 is preferably a 3/2-way valve; the connection of the pump outlet side of the recirculating pump 21 is between this magnetic reversing valve 24 and the 3/3-way magnet valves provided for the traction control functions. The structure of the recirculating pump 21 may be such that, as schematically shown in the drawing, this pump has a piston 21c which is biased by a spring 21b and driven by a cam 21a. To achieve startup movement traction control or an aid in uphill movement starting, the driver of the vehicle equipped with this kind of modified brake system actuates the brake to stop the vehicle, while the vehicle is stopped, and also, by manual actuation of a switch 25 connected to the power source UB, brings about the switchover of the reversing magnet valve 24 to attain traction control (ASR) functions; this valve will hereinafter be called the ASR valve. If the driver now trips the brake, then because the ASR valve 24 has been switched over into its other position, the brake pressure previously brought to bear by the driver is fed into the driven axle. Startup signals or the instant for startup can be ascertained by using already existing sensors; e.g., disengagement of the clutch (with standard transmissions), corresponding signals in the case of an automatic transmission, or actuation of the gas pedal, taking a minimum engine rpm into account and using it. This is followed first by triggering of the ABS control valves 15a, 15b, here embodied as 3/3-way valves, into the third position, in which the brake pressure that has been fed in and so far maintained is relieved by flowing into the end chamber of tank 17. The process then continues as follows. If the vehicle is set into motion without excessive loss of traction, as detected by the already existing ABS wheel sensors, then when a certain speed is attained, which may be on the order of 40 km/h (25 mph) , the ASR magnet valve 24 is de-excited, and by briefly triggering the recirculating pump motor, the volume of pressure fluid relieved into the end chamber of tank 17 is returned to the master brake cylinder. On the other hand, if on starting to move an an excessive loss of traction (spinning) is detected at a wheel, then with the ABS control valves now back in the first position that assures normal communication between the master brake cylinder and the wheel brake cylinders, although the communication with the master brake cylinder is still interrupted by the position of the ASR valve, brake pressure is generated by immediately triggering the recirculating pump; as noted, this pressure is blocked off toward the master brake cylinder 10 by the excited ASR magnet valve 24, and is now modulated as required in the wheel brake cylinder of the spinning wheel by the ABS control valves 15a or 15b, suitably triggered for attaining traction control functions. It is recommended that the control algorithm in the ABS/ASR control unit be made such that primarily, only one driven wheel at a time is braked, the goal being synchronization of the wheel speeds of the driven wheels so as to provide a locking differential effect. If under special circumstances both of the driven wheels are spinning, then excessive engine torque is fundamentally present; automatic intervention can be made in a known manner by controlling the engine torque, for instance by acting on the throttle valve, and the drive power produced by the engine can be reduced; optionally, taking the driver into account, the driver can be informed of this situation by an optical and/or acoustical signal, so that the driver himself can reduce the gas pedal position. Since the recirculating pump 21 attempts to pump the entire volume previously stored in the tank 17 back out again, yet the need for braking a spinning wheel may sometimes be less, it is advantageously possible, to avoid an undesirable overpressure, to effect a corresponding relief of excess pressure, by providing an overpressure valve 26 and switching it such that in the excited or triggered position of the ASR magnet valve 24, the outlet side of the recirculating pump 21 communicates with the tank 17. As a result, on the one hand, depending on the design of the overpressure check valve 26, the maximum pressure that can be generated by the recirculating pump 21 is limited; on the other hand, the originally captive volume of pressure fluid is as a result made to recirculate constantly, and so it can be drawn on as needed for brake pressure modulation. It is appropriate to allow use of the traction control or ASR only within a limited speed range (for example, up to 40 km/h maximum). If a suitably set limit speed is exceeded, the recirculation of pressure fluid volume into the master brake cylinder is effected, as described above, by triggering of the recirculating pump once the ASR magnet valve 24 has been switched back. To assure that brake actuation is possible at any time, even with the ASR magnet valve 24 triggered, a one-way or check valve 27 is finally also incorporated with a parallel fluid flow relative to the ASR magnet valve 24, in the direction of the wheel brake. The exemplary embodiment of the invention shown in the drawing has a hydraulic function switching layout for front- or rear-wheel brake circuit distribution; with a diagonal distribution, logically, two ASR magnet valves 24, check valves and overpressure valves are necessary. The flow chart shown in FIG. 2 for program controlled traction control or aiding in starting movement uphill that follows shows the functions as explained above that are to be performed by the control unit or computer, not shown. It will be understood that the invention is preferably used as part of a program controlled system on the part of the electronic ABS/ASR control unit; the ASR functions can for instance be called upon actuation of the switch or starting aid key 25--that is, upon switchover of the ASR valve 24 into the second position shown in the drawing. The foregoing relates to a preferred exemplary embodiment of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.
A system for traction control (ASR) and an aid for initiating movement on an incline for spinning wheels in an anti-skid brake system (ABS) having ABS multi-positional control valves between the wheel brake cylinders and the master brake cylinder. The system includes a tank chamber for receiving a volume of pressure fluid, and a recirculating pump for pumping fluid during a traction control. The driver first actuates the brake to stop the vehicle, then by switch actuation, triggers an ASR reversing valve that interrupts fluid communication with a master brake cylinder, whereupon on starting movement, the ABS control valves are triggered to relieve the brake pressure into the tank chamber and then, if a wheel is spinning, the recirculating pump for generating brake pressure and the ABS control valve acted upon it for ASR brake pressure modulation are selectively triggered.
8
BACKGROUND OF THE INVENTION In a patent application filed concurrently herewith and commonly assigned, the preparation of substituted spiro (isoxazolidine-3,2'-tricyclo[3.3.1.1 3 ,7 ]decane) derivatives (I) is described. 2-Adamantanone is reacted with an N-substituted hydroxylamine to furnish an adamantyl nitrone which is then reacted with a substituted olefin. The nitrone undergoes a 1,3-dipolar cycloaddition reaction to provide the decane derivatives (I). This preparation scheme is illustrated below: ##STR1## We have now found that 2-(substituted amino)-2-[2-hydroxy-2-alkyl (or phenyl)ethyl]tricyclo[3.3.1.1 3 ,7 ]decane hydrohalide can be prepared from I by opening the heterocyclic ring. The new compounds possess anti-inflammatory, analgesic, anticonvulsant and/or antihypoxia activity. BRIEF SUMMARY OF THE INVENTION According to this invention there is provided a compound having the formula: ##STR2## Where R 1 is lower alkyl, Where R 2 is branched or unbranched alkyl containing 1 to 18 carbons, phenyl, or phenyl which is mono- or disubstituted with lower alkyl, lower alkoxy, halogen, nitro and combinations thereof, and Where X is Cl, Br, or I. DETAILED DESCRIPTION The heterocyclic ring of the spiro(isoxazolidine-3,2'-tricyclo[3.3.1.1 3 ,7 ]decane) derivatives (I) can be opened to prepare the compounds of the invention by either catalytic hydrogenation of their hydrohalide salts in the presence of a palladium catalyst or by zinc-acetic acid reduction according to the following scheme: ##STR3## Where R 1 is lower alkyl Where R 2 is branched or unbranched alkyl containing 1 to 18 carbons, phenyl, or phenyl which is mono- or disubstituted with lower alkyl, lower alkoxy, halogen, nitro and combinations thereof, and Where X is Cl, Br, or I. As used herein, lower alkyl and lower alkoxy mean straight and branched chain alkylene groups which contain 1 to 6 carbons and halogen means Cl, Br, I, and F. The following examples illustrate the preparation of various compounds of the invention. Melting points were determined on a Thomas-Hoover capillary melting point apparatus and are uncorrected. EXAMPLE 1 Preparation of 2-(2-Hydroxyoctyl)-2-(methylamino)tricyclo[3.3.1.1 3 ,7 ]decane Hydrochloride (1) Zinc dust (14 g.) was added portionwise to a solution of 6.56 g. (20 mmol) of the hydrochloride salt of 2-methyl-5-hexylspiro(isoxazolidine-3,2'-tricyclo[3.3.1.1 3 ,7 ]decane) in 200 ml of 50% by volume aqueous acetic acid. The resulting suspension was heated to 65°-70° C. for 7 hours, then filtered, and the inorganic residue washed with 100 ml of hot water. The combined filtrate was neutralized with 160 g. of sodium bicarbonate and extracted with 500 ml of ether. The organic layer was dried over anhydrous magnesium sulfate and then saturated with hydrogen chloride gas in order to give the hydrochloric salt 1 as a white precipitate. Crystallization of the latter from 50 ml ethyl acetate gave 5.07 g of pure 1 (Mp 182°-185° C.). The compound 1 when tested on rats had antihypoxia and anti-inflammatory (carrageenen-induced rat paw assay) activity. EXAMPLE 2 The 2-(ethylamino)-2-[2-hydroxy-2-phenylethyl]tricyclo[3.3.1.1 3 ,7 ]decane hydrochloride (2) (Mp 241°-244° C.) was prepared from 2-ethyl-5-phenylspiro(isoxazolidine-3,2'-tricyclo[3.3.1.1. 3 ,7 ]decane) hydrochloride by a procedure similar to that described in Example 1. The compound 2 when tested on rats had anticonvulsant, antihypoxia, analgesic, and anti-inflammatory activity. EXAMPLE 3 Preparation of 2-(2-Hydroxyoctadecyl)-2-(methylamino)tricyclo[3.3.1.1 3 ,7 ]decane Hydrochloride (3) 5-(Hexadecyl-2-methylspiro(isoxazolidine-3,2'-tricyclo[3.3.1.1 3 ,7 ]decane) hydrochloride (10.0 g, 0.2 mol) was added in one portion to a solution of 1.0 g. of 5% palladium on carbon in 200 ml of acetic acid. The mixture was hydrogenated in a Parr apparatus at room temperature for 72 hours. The reaction mixture was filtered and the filtrate was evaporated under reduced pressure at a temperature of 40° C. The crude, oily residue was dissolved in 250 ml of methylene chloride and washed sequentially with 100 ml of 8 percent by weight aqueous sodium bicarbonate, 100 ml water and 100 ml of brine. The organic extract was dried over anhydrous magnesium sulfate and evaporated to yield a yellow oil which solidified on standing. Subsequent purification by flash chromatography and treatment with ether saturated with hydrogen chloride gas provided 2.76 g of 3 (Mp 145°-149° C.). Additional compounds of the invention were synthesized in Examples 4 to 9 by procedures similar to that of Example 3. EXAMPLE 4 2-(2-Hydroxyhexyl)-2-(methylamino)tricyclo[3.3.1.1 3 ,7 ]decane hydrochloride 4 (Mp 181°-185° C.) was prepared from 5-butyl-2-methylspiro(isoxazolidine-3,2'-tricyclo[3.3.1.1 3 ,7 ]decane) hydrochloride. EXAMPLE 5 2-(2-Hydroxydecyl-2-(methylamino)tricyclo[3.3.1.1 3 ,7 ]decane hydrochloride (5) (Mp 162°-166° C.) was prepared from 2-methyl-5-octylspiro(isoxazolidine-3,2'-tricyclo[3.3.1.1. 3 ,7 ]decane) hydrochloride. EXAMPLE 6 2-(2-Hydroxyduodecyl)-2-(methylamino)tricyclo[3.3.1.1 3 ,7 ]decane hydrochloride (6) (Mp 156°-158° C.) was prepared from 5-decyl-2-methylspiro(isoxazolidine-3,2'-tricyclo[3.3.1.1. 3 ,7 ]decane) hydrochloride. EXAMPLE 7 2-(2-Hydroxyhexadecyl)-2-(methylamino)tricyclo[3.3.1.1 3 ,7 ]decane hydrochloride (7) (Mp 148°-152° C.) was prepared from 2-methyl-5-tetradecylspiro(isoxazolidine-3,2'-tricyclo[3.3.1.1. 3 ,7 ]decane) hydrochloride. EXAMPLE 8 2-(2-Hydroxyeicosyl)-2-(methylamino)tricyclo[3.3.1.1. 3 ,7 ]decane hydrochloride (8) (Mp 141°-145° C.) was prepared from 2-methyl-5-oxtadecylspiro(isoxazolidine-3,2'-tricyclo[3.3.1.1. 3 ,7 ]decane) hydrochloride. EXAMPLE 9 2-(2-Hydroxy-2-phenyl)ethyl-2-(methylamino)tricyclo[3.3.1.1. 3 ,7 ]decane hydrochloride (9) (Mp >210° C.) was prepared from 2-methyl-5-phenylspiro(isoxazolidine-3,2'-tricyclo[3.3.1.1 3 ,7 ]decane) hydrochloride.
2-(Substituted amino)-2-[2-hydroxy-2-alkyl (or phenyl)ethyl]tricyclo[3.3.1.1 3 ,7 ]decane hydrohalides are described such as 2-(2-hydroxyoctyl)-2-(methylamino)-tricyclo[3.3.1.1 3 ,7 ]decane hydrochloride. The compounds possess anti-inflammatory, analgesic, anticonvulsant and/or anti-hypoxia activity.
2
FIELD OF THE INVENTION The present invention relates to a device, system and method for lubricating bearings in refrigerant compressors. More particularly, the present invention relates to a device, system and method in which a lubricant which has been dissolved in a liquid refrigerant is deposited on a bearing in sufficient quantity to provide for the lubrication thereof by vaporizing the liquid refrigerant at a point proximate the bearing to be lubricated. BACKGROUND OF THE INVENTION At the present time, most refrigeration systems utilize two partially miscible fluids; a refrigerant for heat transfer, and a lubricant for lubricating machine elements in the compressor, such as bearings and the like. The lubricant is necessary because refrigerants typically do not have adequate viscosity or lubricity for lubrication purposes. Because it is impractical to completely seal the two fluids from each other within the compressor, refrigeration systems are designed to manage the degree and locations where the mixing of these two fluids can occur. Compressors typically have a separate sump, pumping means, and distribution system for the lubricating oil, all isolated, but not sealed from the refrigerant. Pressure, temperature and mechanical separation means are employed to maintain a sufficiently oil rich mixture in the sump for reliable lubrication, typically no more than 20% refrigerant by weight. Refrigeration systems are also designed to limit the amount of oil discharged into the heat transfer devices, such as the evaporator, to avoid fouling and associated loss of system efficiency. Solubility characteristics between the fluids are tailored to minimize the amount of dissolved refrigerant in the oil sump, yet provide sufficient solubility in the evaporator, condenser, and interconnecting piping to assure oil leaving the compressor returns via entrainment in the circulating refrigerant. The need to maintain an oil rich fluid in the sump, and limit the build up of oil in the evaporator, over the wide range of operating conditions common in refrigeration systems, usually necessitates complex and costly control systems and fluid separation features. Loss of control of the two fluids during extreme system operating conditions is a common cause of compressor failures, particularly compressor bearing failures, due to excessive refrigerant buildup in the sump. For these reasons, efforts have been directed to elimination of the need for oil separation, and to use the refrigerant rich lubricating fluids naturally residing in the evaporator or condenser for lubrication purposes. A typical refrigeration system includes a compressor, condenser, expansion valve, and evaporator. Compressed refrigerant rich gas typically containing less than 2% oil is discharged from the compressor into a condenser where heat rejection transforms the refrigerant into a liquid. The mixture then passes through an expansion valve into the evaporator, where absorbed heat transforms the liquid mixture back into a gaseous refrigerant and liquid oil. As the mixture is discharged from the compressor, the oil is mechanically separated into a sump and the refrigerant is channeled into the compression process. In the specific case of oil flooded screw compressors, the mixture of oil and refrigerant discharged from the compressor is passed through an oil separator, where droplets containing 80% oil/20% refrigerant are collected for lubrication and oil sealing purposes. Various efforts have been reported in the prior art to use oil and refrigerant mixtures as part of a lubrication system. Zimmern et al. U.S. Pat. No. 4,589,826 proposes a method of lubricating bearings in a compressor in which a refrigerant gas loaded with oil in the form of a mist is delivered to the bearings. This system requires a two phase system of gaseous refrigerant and oil droplets, and requires equipment to mix a known quantity of oil in a refrigerant gas. The parent application of Zimmern et al., Noda et al. U.S. Pat. No. 4,553,399 discloses transferring a liquid refrigerant having oil dissolved therein to a casing of the compressor motor to vaporize the refrigerant, to form a two phase mixture with oil droplets in a gas mixture. The two phase mixture is then transferred to the bearings or other parts needing lubrication. In an alternative embodiment, the oil itself is transferred to the bearings after the gaseous refrigerant has been removed by vaporization using the heat of the motor. In both Noda et al. and Zimmern et al., attempts are made to lubricate bearings with gaseous refrigerants and droplets of lubricating oil, typically in concentrations of less than 2% or 3% by volume of oil. One of the earliest designs for refrigeration machines having lubrication is disclosed in Stair U.S. Pat. No. 1,195,162. In the Stair patent, the lubricant is separated from the refrigerant by centrifugal force, one of many means of separation of oil from refrigerant that may be used. Finally, two patents to Shaw, U.S. Pat. Nos. 4,375,156 and 4,439,121, disclose transfer of oil in a mist form, representing a two phase mixture of oil mist in gaseous refrigerant. Accordingly, it is an object of this invention to provide an improved device, system and method for lubricating bearings and the like in refrigerant devices such as refrigerant compressors. Another object of the present invention is to provide a device, system and method for using the oil contained in liquid refrigerant to lubricate bearings utilizing the heat generated by the bearing as the refrigerant vaporizing means and the like which in accordance with the preferred embodiment of the invention without use of expensive and complicated separation devices. Other objects will appear hereinafter. SUMMARY OF THE INVENTION It has now been found that the above and other objects of the present invention may be accomplished in the following manner. Specifically, an improved lubrication device, system and method of its use has been invented. The invention provides for lubrication of at least one bearing in a flow path defined for a refrigerant/oil mixture such that the bearing is in a portion of the flow path. A fluid comprising a small quantity of oil dissolved in liquid refrigerant is carried through that portion of the flow path in which the bearing is disposed at a slow flow rate. Means are provided for vaporizing at least a portion of the liquid refrigerant at a location proximate the bearing to thereby release and deposit oil on the bearing in sufficient quantity to provide for the lubrication thereof. The oil is deposited by control of flow rate, heat and pressure drop at the bearing being lubricated. The term oil, as used herein, is intended to include natural and synthetic oils and other lubricants which are compatible with refrigerants used devices of the type described herein. This invention provides a means of reliably lubricating rolling bearings in refrigerant compressors with refrigerant/oil mixtures which would normally have inadequate viscosity for such purposes. It has been discovered that, generally speaking, mixtures containing less than about 75% oil by weight can not sustain an oil film in rolling element bearings and therefore are unsuitable for lubrication purposes. In conflict with this requirement is the need to restrict oil concentration to 5% or less in the heat exchangers of a refrigeration system. The presence of oil in a heat exchanger negatively affects heat transfer and overall system efficiency. This invention provides a means for using a refrigerant rich mixture communicated from either an evaporator or condenser, to lubricate rolling element bearings by a process which concentrates the oil to a level suitable for the lubrication of such bearings. The concentration of oil is achieved by movement of the mixture into the two phase region of its pressure-enthalpy region to release an oil rich fluid for lubrication purposes on the bearing. The success of the present invention may be accomplished in two ways. In one, the mixture is "flashed" from a high pressure condenser, rapidly dropping the pressure such as by metering it through a flow restricting orifice, thereby vaporizing refrigerant and releasing an oil rich fluid for lubrication purposes. In the other way, starting with low pressure liquid from an evaporator, the addition of heat has the same affect. Bearing frictional heat plays a significant role in the enrichment process if flow rates are limited to the low levels typical of spot or mist lubrication methods (centiliters rather than liters per minute). At such low flow rates, bearing frictional heat, or bearing frictional heat combined with reduction of pressure, is sufficient to evaporate the refrigerant. Liquid refrigerant buildup in the bearing cavity should be limited to facilitate efficient vaporization and thereby concentration of oil. The principal advantage of this invention is that the use of lubricating fluids naturally residing in either a low pressure evaporator or a high pressure condenser avoids the need for expensive and complicated mechanical oil separators, and avoids the need for a separate oil sump and associated sealing elements. This is particularly true in screw compressors using liquid refrigerant injection instead of oil injection to cool and seal the compression process since an oil separator would only be needed for bearing lubrication. Another advantage is that significantly reduced bearing friction is achieved due to low oil flow which may be as low as that used in spot or mist lubrication. The invention requires that temperature, pressure and flow rate for the mixture be controlled to accomplish the vaporization of refrigerant from the mixture and the deposition of the remaining oil on the bearing. Proper control of these variables will insure good lubrication in accordance with the invention. In the preferred embodiment of the invention, bearing frictional heat alone or bearing frictional heat in combination with a pressure drop is used to vaporize refrigerant and deposit oil on the bearing. The volume of oil dissolved in the liquid refrigerant will be small, typically in the range of 0.5% to about 5.0% by weight. Preferably the concentration of oil in the liquid refrigerant in contact with the bearing should be at least 75% oil, based on the total weight of liquid. The invention may also be employed in more sophisticated designs, such as where pressure, temperature and flow sensors, and heaters are utilized at the location of the bearing to monitor and control the vaporization of refrigerant to enrich the oil concentration to 75% or more. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects of the present invention and the various features and details of the operation and construction thereof are hereinafter more fully set forth with reference to the accompanying drawings, where: FIG. 1 is a schematic view of a typical refrigeration system employing the concepts of the preferred embodiment of this invention. FIG. 2 is a pressure-enthalpy diagram for a particular refrigerant, illustrating a typical refrigeration cycle. FIG. 3 is a schematic illustration of bearing lift-off speed as a function of variations in temperature and pressure. FIG. 4 illustrates the equilibrium relationship of refrigerant/oil mixture for various pressures and temperatures. FIG. 5 shows the influence of mixture composition and temperature on viscosity. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a typical refrigeration system, consisting of a compressor 31, a condenser 32, an expansion valve 33, an evaporator 34, and the associated interconnecting piping. Refrigerant/oil mixtures typically reside in liquid form in both the evaporator and the condenser. Typical evaporator conditions in R134a: 45 psia and -1° C. Typical condenser conditions: 160 psia and 100° C. Systems are usually designed such that the fluid returning to the compressor through suction line 35 consists of vaporized refrigerant which may or may not contain droplets of oil. In the case of flooded type evaporators commonly used with centrifugal compressors, oil tends to remain in solution in the evaporator rather than return in droplet form. In direct expansion evaporators, commonly used with reciprocating, screw, and scroll compressors, oil droplets return to the compressor entrained in the vaporized refrigerant, and circulate through the entire system. A typical flooded evaporator 34 contains a bath of liquid refrigerant, through which a second liquid flows isolated within passage ways. In a direct expansion evaporator, the refrigerant flows through the passage ways, isolated from and surrounded by the second fluid. In both cases heat transfer from the second fluid vaporizes liquid refrigerant. FIG. 2 illustrates the process on a standard pressure--enthalpy diagram for refrigerant R-134a, describing a cycle that is typical for most refrigerant systems. Refrigerant vapor is compressed from state point G to F in the compressor. Heat is rejected in the condenser from F to A, condensing the vapor back into a liquid phase. Reexpansion A to B occurs as the fluid passes through a metering device which lowers the pressure from the high pressure in the condenser to the low pressure in the evaporator. In this process most of the fluid remains liquid at state point D, and a portion vaporizes to a gas at state point E. Heat absorbed in the evaporator vaporizes the remaining refrigerant to state point E. To assure that no incompressible fluids return to the compressor, the vaporized gas is often super heated to state point G. An oil film separating a rolling element from a raceway is essential for reliable lubrication of rolling element bearings. In laboratory investigations, the presence of such an oil film was established using lift off speed as a criteria. The formation of an oil film is highly dependent on lubricant viscosity and bearing rotational speed; higher viscosity and speed improves film formation and thickness. Lift off is defined as the minimum speed required to prevent metal to metal contact between raceway and rolling element. Low lift off speed is a criteria for efficient film formation. From measurements of lift off speed as a function of bearing cavity pressure and outer ring temperature, it was possible to develop the map of lift off speed as a function these variables shown in FIG. 3. For an understanding of FIG. 3, it is necessary to consider first how pressure and temperature influence composition of the refrigerant/oil mixture, FIG. 4, and secondly how mixture composition and temperature influence viscosity, FIG. 5. To achieve low lift off speeds, the lubricant must have sufficiently high viscosity. In the two phase region of the pressure--enthalpy chart, FIG. 2, any mixture of oil and refrigerant will be in equilibrium with a vapor phase of the refrigerant, so that the equilibrium concentration of refrigerant in oil is highly dependent on pressure and temperature. FIG. 2 is for refrigerant only, but may be used to describe approximately the behavior of refrigerant rich solutions of both oil and refrigerant. FIG. 4 is complimentary to FIG. 2 and shows the dependence of mixture composition upon pressure and temperature for the oil rich fluids necessary to provide good bearing lubrication. FIG. 5 shows the influence of mixture composition and temperature on viscosity. The experimental observations shown in FIG. 3 can be explained by considering specific combinations of bearing outer ring temperature, and lift off speed from FIG. 3, in relationship with equilibrium concentrations in FIG. 4. In the experiments, a ball bearing of size 6204 was used. In order to make the experimental results independent of bearing size, the NDM speed concept is useful. This is done by multiplying the bearing mean diameter DM with the bearing speed N. The mean diameter for bearing size 6204 is 33.5 mm, therefore at 1000 rpm the NDM speed is 33,500. The experimental data is valid for polyolester oil and R134a refrigerant. The data in the table below are taken from FIG. 3 and FIG. 4. ______________________________________POINT H I J K______________________________________Lift off speed NDM (FIG. 3) 50000 30000 20000 15000Outer ring temp °C. (FIG. 3) 19.0 20.0 14.0 5.5Pressure, bar (FIG. 4) 5.15 4.46 3.77 3.08Oil Dilution % (FIG. 4) 27% 23% 25% 25%______________________________________ These results show that bearing oil film formation was achieved at a refrigerant dilution of approximately 25%, or in other words, 75% concentration of oil. Turning back to FIG. 1, an embodiment of the invention, Alt 1, is shown, applicable to systems with oil present in the condenser, such as screw compressor driven systems. The refrigerant rich mixture from the condenser, state point A, is flashed through orifice 36 into bearing cavity 37 and state point B. This process alone releases some oil rich fluid for lubrication purposes. Frictional heat from bearing 38 vaporizes additional refrigerant and releases additional oil. Total flow and amount of fluid in the bearing cavity must be kept low enough such that bearing frictional heat, and heat from adjacent components is sufficient to vaporize liquid refrigerant to concentrate the oil to 75% or more. For systems with large fluctuations in operating conditions or shaft speed, an auxiliary heat source 39 and flow control devices 16 and 17 can be added to assure adequate vaporization at all operating conditions. Control of flow is achieved with flow meter 16 and flow control valve 17. Auxiliary heat input could be controlled using pressure sensor 40 and temperature sensor 41 to assure conditions favorable for vaporization and deposition of oil on the bearings. Bearing cavity 37 is vented back to the suction line via line 42. In this embodiment naturally occurring system pressure differentials can be used to circulate the lubricant, avoiding the need for a lubricant pump. An alternative embodiment, Alt 2, of the present invention is also shows in FIG. 1. In Alt 2, oil resides in the evaporator and does not pass through the compressor into the condenser, such as a flooded evaporator combined with a centrifugal compressor. In this case, all of the oil is mixed with liquid refrigerant at state point D in the evaporator. Pump 43 delivers the refrigerant rich mixture through flow meter 18 and orifice 36 into bearing cavity 37. In this case, pump speed and flow rate can be controlled by flow meter 18. The only function of orifice 36 is to atomize the mixture for better distribution within the bearing cavity. Bearing frictional heat, heat from adjacent components, and an auxiliary heat source 39 are combined to vaporize liquid refrigerant; from state point D to E. This alternative requires a greater amount of heat for vaporization because of starting from D rather than B as in the high side alternative above. Pressure and temperature sensors 40 and 41 can be employed for control purposes as described above. Line 45 is provided to transport lubricant to multiple bearings of the compressor 31 regardless of which alternative source, condenser 32 or evaporator 34, is used. In summary, the present invention provides for an improved lubrication device, system and method, where a small quantity of a refrigerant/oil mixture is introduced to the region proximate a bearing under flow rate, temperature and pressure conditions which vaporizes the refrigerant and deposit a lubricant containing at least 75% oil by volume on the bearing(s). The heat generated by the bearing(s) provides the refrigerant vaporizing means either alone or in combination with auxiliary heating means or pressure control means depending on the compressor system configuration. Other modifications and embodiments will become apparent to those skilled in the art upon reading the above disclosure.
A refrigerant device comprising at least one bearing disposed in a housing having a refrigerant flow path. The bearing is contacted with a lubricant charge of a small quantity of lubricant dissolved in liquid refrigerant. At least a portion of the liquid refrigerant proximate the bearing is vaporized to deposit lubricant on the bearing in sufficient quantity to provide for the lubrication thereof. The refrigerant may be vaporized by heat or by pressure drop, or by both. A sensor may be provided to monitor or control temperature and pressure conditions to insure that sufficient refrigerant is vaporized to form a lubricant liquid of at least about 75% lubricant by volume.
5
BACKGROUND OF THE INVENTION 1. The Field of the Invention This invention relates to router guides used in woodworking for guiding a router in making a groove in a piece of wood. Specifically, it is a router guide which allows the user to cut grooves such as dadoes of different widths with a single router bit. 2. Description of the Related Art The prior art shows various types of devices used to make routers easier to use and to help the user to make cuts and grooves in wood. Examples of patents related to the present invention are as follows, and each patent is herein incorporated by reference for the supporting teachings: U.S. Pat. No. 5,738,470, is a guide device for cutting a groove. In the device of this invention, a rectilinear guide member comprises a pair of guide members, where the opening width of an opening defined between the guide members is set to be the same as the diameter of a rotary bit of a router. A dado having a width that is the same as the thickness of a board to be used as a shelf is formed by operating the router with a scrap piece of that board inserted between the guide members to get an accurately cut dado. U.S. Pat. No. 3,782,431, is a tool for use by a carpenter, used particularly in cabinet construction work, the tool comprising, a guide for a router, wherein the guide is adjustable, the guide being comprised of a pair of parallel guide bars interconnected by transverse extending adjustable bolts for selectively spacing the guide bars apart, and a plurality of transverse extending clamps extending across the guide bars for locating the router position. U.S. Pat. No. 4,770,216, is a fixture which allows cuts to be made in a board with a hand held router in both a longitudinal and transverse direction of such board. The fixture includes a pair of first members of predetermined length. A pair of second members of shorter predetermined length is secured to a first pair of members such that in an assembled relationship they form a rectangle. At least one T-shaped slot is formed in each of the first pair of members and a notch is formed in at least one of the second pair of members intermediate to the ends thereof. U.S. Pat. No. 5,203,389, is a multi-purpose woodworking fixture having a structure for facilitating precision-controlled positioning of a woodworking tool, such as a router, about a wood workpiece for cutting wood-joint cuts, wood molding, or geometric designs. The fixture facilitates making a variety of the common wood-joints including dovetail joints, box joints, dado joints, dovetail-dado joint, rabbet joints, combination rabbet and dado joints, mortise and tenon joints, mortise and mortise joints, biscuit joints, lap joints, cross lap joints, end lap joints, dowel joints, spline joints, tongue and groove joints and stile and rail joints. The fixture features a router carriage, a detachable calibrated router positioning mechanical attachment for positioning the router in the X-direction and Y-directions and which complements the router's adjustment in the Z-direction. The fixture enhances the router's capabilities for controllably working on the workpiece, either in a freehand manner or by using, the calibrated router positioning mechanical attachment, either manually or with an optional motorized means. U.S. Pat. No. 5,101,875, is a router base and combination router and base for use as a guide in making a dado, rabbet groove, or similar cuts, which has a plurality of peripheral edge segments spaced different distances from the center line of the router bit. The base provides for making one or more cuts of varying distances from a conventional fence without adjusting the fence. U.S. Pat. No. 5,533,556, is a router guide comprising, a channeled track with a fixed fence attached at a top surface on a first end and a moveable fence slidably attached between the first end and the second end. The track affixes to one side of the workpiece and a router attached to a circular disk is manually slid between the fences to cut slots in the workpiece. The fences are rotatable to a plurality of angles to the track. A pair of router stops may be attached to the fences to limit the sliding motion of the router. U.S. Pat. No. 5,240,052, is a precision router guide for guiding a router in the formation of grooves, slots, steps or other cutaway sections of various widths in a work piece. The precision router guide includes a rectilinear guide member with an integral clamping assembly for securing the guide member to a work piece, and an adjustable template assembly adapted to be slidingly coupled to the guide member. The adjustable template assembly is configured to receive a router base, and provides for the router bit to extend through an opening into engagement with the work piece. The adjustable template assembly also includes two adjustable guide elements and one fixed and one adjustable stop designed to allow adjustable movement between the router base and the template assembly in a direction perpendicular to the guide member, the amount of such movement being determined by the desired width of the cut. Adjustable pointers are provided on the template assembly to enable the groove, slot, step or other cutaway section to be precisely located on the work piece. The foregoing patents reflect the state of the art of which the applicant is aware and are tendered with a view toward discharging applicant's acknowledged duty of candor in disclosing information that may be pertinent in the examination of the application. It is respectfully stipulated, however, that none of these patents teach or render obvious, singly or when considered in combination, applicant's claimed invention. PROBLEMS WITH THE PRIOR ART Routers are woodworking tools used to make grooves along the length or width of a material. Movable handheld routers are capable of producing precise edges and decorative designs as well as grooves such as dadoes, rabbets, and other similar groove cuts. These powered routers are becoming increasingly popular and common among both professional and hobbyist woodworkers. In using a router, the woodworker typically clamps a straightedge to the material being cut and secures the material to a work surface. This surface usually has a second straight edge, or "fence" which is used to help the woodworker to cut in a straight line. The groove to be cut is made by guiding the router along this fence. Routers have several characteristics which make their use difficult, time consuming, and potentially wasteful of material. First, variances in the density of the material being cut or imperfections such as warping in the material make cutting a straight line with a router very difficult. Users often spend much time making customized guides or patterns for specific projects or operations. Further, often the groove being cut needs to be wider than the width of the router bit. One method for making grooves wider in the prior art was to change router bit sizes when needed. This process has historically been time-consuming and clumsy. Another method for increasing the width of grooves was to repeatedly move and reclamp either the fence or the material being cut with each pass made with the router until the groove had reached the desired width. By introducing this step of moving or repositioning the fence or the material being cut, however, the effort and time needed to complete a project were increased. In addition, the potential for inaccuracy was greatly increased by the repositioning of the pieces. Each reposition of the components required remeasuring to assure that the new position would allow the proper cut to be made, and each reposition could introduce either the chance that another cut would be needed to make the requisite width, or the danger that too much will be cut away, leaving a groove which is unusably wide. As a result, time and potentially material are wasted by using the methods known in the prior art. There is thus a need for a router guide which effectively guides the user in cutting alone straight lines with a hand router, while allowing the user to cut grooves of different widths with a single router bit. SUMMARY OF THE PREFERRED EMBODIMENT It is a feature of the invention to provide a router guide, used to cut grooves of varying widths with a router bit of fixed size. In particular, there is a router guide which performs better than those disclosed in the prior art. A further feature of the invention is to provide a router guide, comprising a base plate, having a guide edge, a depression, and a first hole; and a rotating plate, set into the depression in the base plate, which rotates around a first hole central axis of the first hole, having a second hole located substantially over the first hole, but having a second hole central axis that is offset by a distance. It is an additional feature of the invention to provide a router guide, wherein the first hole is larger than the second hole, thus allowing the router bit to rotate around a first hole central axis of the first hole. A further feature of the invention is to provide a router guide wherein the base plate has a guide edge which is used to align the guide with a guide fence. An additional feature of the invention is to provide a router guide wherein the rotating plate is circular. The invention resides not in any one of these features per se, but rather in the particular combination of all of them herein disclosed and claimed, and it is distinguished from the prior art in this particular combination of all of its structures for the functions specified. There has thus been outlined, rather broadly, the more important features of the invention so that the detailed description thereof that follows may be better understood, and so that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter which would form the subject matter of the claims appended hereto. Those who are skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims are regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers, and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, neither is it intended to be limiting as to the scope of the invention in any way. Other features of the present invention will become clearer from the following detailed description of the invention, taken with the accompanying drawings and claims, or may be learned by the practice of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view of a router tool. FIG. 2 is a cutaway view of the router tool shown in FIG. 1 along the line indicated in FIG. 1. It is noted that the drawings of the invention are not to scale. The drawings are merely schematic representations, not intended to portray specific parameters of the invention. The drawings are intended to depict only typical embodiments of the invention, and therefore should not be considered as limiting the scope of the invention. The invention will be described with additional specificity and detail through the use of the accompanying drawings. Like numbering used on different drawings represents like elements. Charter by the U.S. Constitution This disclosure of the invention is submitted in furtherance of the constitutional purposes of the United States Patent Laws "to promote the progress of science and useful arts," as stated in Article 1, Section 8 of the United States Constitution. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 and FIG. 2, there is a top view and a cutaway view of the preferred router tool 10. Specifically, there is a base plate 12, a rotating plate 14, and a retainer 20. Rotating plate 14 rests rotatably in depression 15 in base plate 12. Base 12 further comprises a guide edge 28, which is pressed against a guide fence (not shown) to assure that the router traverses along straight lines in successive cuts in the same region. A router 30 will be mounted to the rotating plate 14 by attachment points 21, such that the router bit (not shown) will fit through first and second holes 17 and 19. Center line 16 runs through the first hole central axis 25 of first hole 17 in base 12. Center line 18 runs through the second hole central axis 27 of second hole 19 in rotating plate 14. Base 12 slidably lays on board 23 for cutting a groove (not shown)along center line 18. Uniquely, center line 18 and hole 19 are not centrally aligned with base 12. This allows the router bit to rotate about the first hole central axis 25 of first hole 17 as rotating plate 14 is rotated. The distance of the movement is the distance between center line 16 and center line 18, which is distance 22. This distance may be calibrated to correspond with measurements shown on measurement scale 26. When indicator arrow 24 is at the position of FIG. 2, the center line 18 is at its furthest position distal to the guide fence from center line 16. By rotating rotating plate 14 by 90 degrees, center line 18 becomes coextensive with center line 16. In operation, a first cut on board 21 is made when center lines 16 and 18 are coextensive. Thus, a 1/2" router bit will cut an exact 1/2" first groove. An edge of a second board meant to fit within the groove may be abutted to the first groove, or measurements may be noted to determine how much wider the groove needs to be. The rotating plate 14 is then rotated either clockwise or counterclockwise, dependent on which direction the user desires to displace the router bit from the center of hole 17, thus displacing center line 18 from center line 16 sufficiently to equate distance 22 to the increase in width needed for the groove. Remarks About the Preferred Embodiment One of ordinary skill in the art of designing woodworking equipment will realize many advantages from using the preferred embodiment. First, a skilled artisan would appreciate the use of the invention in cutting grooves such as dadoes, rabbets, and other grooves. Note that the first hole central axis (25) and the second hole central axis (27) are offset from each other, which positions the two holes eccentrically to each other. A skilled artisan would appreciate this eccentricity of second hole 19 on rotating plate 14 from first hole 17 on base plate 12. This eccentricity allows the user to use a router to make grooves of varying widths by making repeated cuts with a single router bit. A skilled artisan would further value the fact that since second hole 19 is always smaller than first hole 17 in the invention, rotation of second hole 19 around the first hole central axis of first hole 17 allows the position of the router bit to change relative to the guide fence. Further, a skilled artisan would recognize that use of an eccentric circular guide allows for very smooth, gradual adjustment of the distance 22 in order to accommodate any needed change in width of the groove within the range of distances possible for distance 22. Similarly, one skilled in the art would recognize the benefits of the retainers 20 for holding the rotating plate 14 in place after adjustments have been made to change the distance between the center lines of the first and second holes, 17 and 19. These retainers hold the rotating plate in a fixed position, thus preventing slippage and unintended changes in the width of the groove being cut by the router. A skilled artisan would similarly appreciate that the design of the guide 10 allows for additional cuts to be made on either side of the original groove, thus being more proximal or more distal to the guide fence. By turning rotating plate 14 clockwise up to 90 degrees, the distal side of the original groove may be widened with additional cuts. Similarly, by turning rotating plate 14 counterclockwise up to 90 degrees, the proximal side of the original groove may be widened with additional cuts. A skilled artisan would also recognize that the device is equally usable to right- and left-handed users by rotating it to abut the guide fence either on the left side of the workpiece. Variations of the Invention A skilled artisan would consider it an obvious design change to use different sizes and dimensions in constructing the apparatus in order to accommodate different types or sizes of routers, router tables, guide fences, and router bits. Further, the dimensions of the first and second holes 17 and 19 in both the base and rotating plates 12 and 14, respectively, may be varied in size and relationship in order to accommodate different sizes and shapes of router bits and thus the desired grooves. In all designs of the invention, however, second hole 19 will have to some extent a diameter smaller than that of first hole 17. Further, a skilled artisan would consider changes to the size and shape of base plate 12 to accommodate the needs or desires of the user to be obvious. These modifications to base plate 12 could include changing its shape to be square, rectangular, etc. Further, the corners of base plate 12 could be rounded. Further, base plate 12 could be constructed of any number of materials, including plastic, metal, and wood, without departing from the scope of the invention. Base plate 12 could likewise be mounted on bearings or other such devices to facilitate motion along the guide fence. Guide edge 28 could similarly use bearings to facilitate sliding along the guide fence. Rotating plate 14 could also be changed in size and shape to any form rotatable in depression 15. Rotating plate 14 could be made large enough, for example, to allow cutting of grooves wider than the router bit as well as entirely separate grooves without unclamping or moving the workpiece or guide fence. Rotating plate 14 could also be mounted on bearings or other similar devices to facilitate its rotation in depression 15 without departing from the spirit of the invention. A skilled artisan would further consider it obvious to increase or decrease the size of rotating plate 14 in relation to base plate 12. Such an artisan would similarly consider it obvious to increase or decrease the sizes of first and second holes 17 and 19 relative to base and rotating plates 12 and 14. It would in like manner not depart from the scope of the invention to increase the size of first hole 17 while decreasing the size of second hole 19 in order to permit a very wide range of grooves of different widths to be cut with a single router bit. Additionally, one skilled in the art would recognize that measurement scale 26 could be extended to cover 1/4, 1/2, or all of the perimeter of rotating plate 14 on base plate 12 to allow freedom of adjustment with indicator arrow 24, and to allow use of the router guide 10 with a guide fence on either the right or the left of the material to be cut to accommodate either right- or left-handed users. Similarly, it would be considered an obvious design change to mark the measurement scale in centimeters, inches, degrees, or other units corresponding either to the degree of the angle between the indicator arrow 24 and center line 16, or to the amount of change of size of the groove which would be caused by making an additional cut with the indicator arrow 24 at a given placement. Similarly, the number, type, and position of retainers 20 could be varied to provide either more or less support of the rotating plate 14 or otherwise facilitate the use of guide 10 without departing from the scope of the invention. While the invention has been taught with specific reference to these embodiments, someone skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and the scope of the invention. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
A router guide is disclosed which is used to cut grooves of varying widths with a router bit of fixed size. The router guide comprises a base plate, having a guide edge, a depression, and a first hole; and a rotating plate, set into the depression in the base plate, that rotates along a central axis of the first hole, having a second hole located substantially over the first hole, but having a center offset by a distance, wherein the first hole is always larger than the second hole.
1
CROSS-REFERENCE TO RELATED APPLICATIONS This application is a 371 of Patent Cooperation Treaty application PCT/US2008/056347 filed Mar. 8, 2008 which claims benefit of U.S. Provisional Application 60/894,196 filed Mar. 10, 2007. TECHNICAL FIELD The invention relates broadly to methods and apparatus employed in the manufacture of devices based on wafers. Examples of such devices include photovoltaic cells, light emitting devices and integrated circuits. More particularly, the invention relates to apparatus and methods for in-line quality control of wafers, such as the quality control in conveyer type high throughput manufacture of silicon solar cells. Whilst this invention has initially been developed for application to photovoltaic cells (and is described herein as such), the invention is not limited to this field. BACKGROUND OF THE INVENTION Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common knowledge in the field. State-of-the-art silicon solar cell production is based on highly automated belt-type conveyor configurations. The as-cut p-type Si wafer is typically first subjected to chemical etching which removes saw damaged layers from both front and back surfaces of the wafer or edge damage from the laser cutting of silicon ribbons and then passes through the consecutive process steps including phosphorous diffusion to form a p/n junction; the deposition and firing of an antireflection Si 3 N 4 coating; the creation of the front-side metal contact grid and Al back-side metal contact. Other modifications to optimize the process are also used in variants of these solar cell process steps. Finally, the individual solar cells are connected sequentially in strings, to achieve required voltage and current, and the strings are laminated into solar panels. The PV industry, with crystalline silicon as a dominant segment, is rapidly expanding to meet growing renewable energy demands all over the world. The silicon wafer is a major contributor to the overall cost of the solar cell: currently up to 75% of the overall cost. One of the major technological problems is the identification and elimination of sources of wafers' mechanical defects such as thermo-elastic stresses and cracks leading to the loss of wafer integrity and ultimately to the breakage of as-grown and processed Si wafers and of PV cell based on these wafers. The price of silicon raw material has grown substantially in the last three years due to a world-wide shortage of polycrystalline silicon feedstock. To compensate for the feedstock shortage, solar Si wafers are sliced thinner to a thickness of less than 100 microns [J. Wohlgemuth, M. Narayanan, R. Clark, T. Koval, S. Roncin, M. Bennett, D. Cunningham, D. Amin, J. Creager “ Large - scale PV module manufacturing using ultra - thin polycrystalline silicon solar cells” Conference Record of the Thirty - First IEEE Photovoltaic Specialist Conference (IEEE Cat. No. 05CH37608), 2005, Pages 1023-1026]. Wafer areas have also been increased to reduce overall production costs, and larger sizes, up to 210 mm×210 mm, are now available. Thinner and larger wafers are, however, more difficult to handle during production, this leads to a reduction in yield due to increased breakage especially in high speed automated manufacture. In-line wafer breakage reduces equipment throughput as a result of down time required for cleaning in-line equipment, and removing broken wafers from fixtures. There is, therefore, a recognized need for devices and a methodology for fast in-line quality control methods and apparatus. Common problem leading to wafer breakage is related to small cracks that under thermal or mechanical stress cause wafer's mechanical fracture. Further, it is recognised that impact of a particular crack on wafer's mechanical property depends on the size of the crack and its location within the wafer. The majority of the methods presented in the prior art are based on imaging techniques, comprising capturing and processing an image of a wafer in order to determine its spatial irregularities. Scanning Acoustic Microscopy (SAM) is an imaging technique using 150 MHz pulses for precise identification and visualization of micro-cracks as small as 10 microns. The cracks are identified as acoustic impedance discontinuity of wafer at the crack region [M. C. Bhardwaj “ Principles and methods of ultrasonic characterization of materials” Advanced ceramic materials, 1 (1986) pp 311-324]. The steps of SAM technique including, immersion of wafer into de-ionized water, mapping of the pulse amplitude, and data analyses are each relatively slow, so that the full testing procedure even in its automated version can occupy several minutes of precious manufacturing time. This evidently makes SAM unsuitable for in-line applications where no more than a few seconds per wafer is acceptable for quality inspection. Another approach is offered by an optical inspection imaging where relatively large cracks are visualized by a light transmission technique [E. Rueland, A. Herguth, A. Trummer, S. Wansleben, P. Fath “ Optical micro - crack detection in combination with stability testing for in - line - inspection of wafers and cells”, Proceedings of 20 th EU PVSEC (Barcelona, 2005) pp. 3242-3245]. This technique, however, lacks the capability to observe small cracks at the wafer's periphery. The optical inspection is also non-applicable to processed wafers having back-side Al contact and to complete solar cells. An additional limitation of the transmission technique is that tightly closed cracks with width of ˜1 micron are not detectable due to the optical diffraction limit. Recently reported data on luminescence imaging [T. Trupke, R. A. Bardos, M. C. Schubert, W. Warta, “ Photoluminescence imaging of silicon wafers”, Applied Physics Letters (2006), Volume 89, Issue 4, 44107; T. Fuyuki, H. Kondo, T. Yamazaki, Yu. Takahashi, Yu. Uraoka “ Photographic surveying of minority carrier diffusion length in polycrystalline silicon solar cells by electroluminescence” Appl. Phys. Letters 86, 262108 (2005)] is particularly developed for testing of indirect band-gap semiconductor devices such as silicon solar cells. As an imaging technique the method's speed is limited by implemented image recognition software, which needs to perform a substantial computational task of analysing complex luminescence image of a wafer. Another drawback of the method is that other defects such as surface scratches and dislocation slip lines can be misinterpreted as cracks thus leading to false positive answers. The application of this method to identification of electrically isolated or poorly connected regions such as those caused by breaks in the metal pattern was disclosed in details in an international patent application PCT/AU2007/000595. Ultrasonic lock-in thermography is sufficiently sensitive, however it requires a longer measuring period for signal averaging due to low infrared intensity [J. P Rakotoniaina, O. Breitenstein, M. H. Al Rifai, D. Franke, A. Schnieder “ Detection of cracks on silicon wafers and solar cells by lock - in ultrasound thermography”, Proceedings of PV Solar conference (Paris, June 2004), pp. 640-643]. A new non-imaging experimental algorithm for fast crack control using Resonance Ultrasonic Vibrations (RUV) was disclosed in the paper [A. Belyaev, O. Polupan, W. Dallas, S. Ostapenko, D. Hess, J. Wohlgemuth “Crack detection and analyses using resonance ultrasonic vibrations in full-size crystalline silicon wafers”, Appl. Phys. Letters 88, 111907-1 (2006). The RUV approach for stress control in silicon wafers was also disclosed in the U.S. Pat. No. 6,413,789 B2 [S. Ostapenko “Method of detection and monitoring stresses in a semiconductor wafer” U.S. Pat. No. 6,413,789 B2]. The method, as described in prior publications, allows for fast detection of wafer's imperfections but is not applicable for in-line control. The method involves measurement of a single resonant curve and correlating one parameter of the curve with the internal stresses or cracks in a wafer. The wafers, however, vary in a range of physical parameters such as lateral dimensions, thickness, and shapes. While small variations of these parameters are acceptable within the quality requirements for PV cells, these variations often lead to false positive events when an acceptable wafer is falsely recognised as a potentially breakable wafer with cracks. Further, the method is not capable to provide an information in relation to the location of crack. Above mentioned shortcoming limit benefits of using the method of U.S. Pat. No. 6,413,789 for in-line quality control of wafers. Another method, based on impact testing is disclosed in the U.S. Pat. No. 5,257,544 titled “Resonant frequency method for bearing ball inspection”. This invention provides a method for detecting defects in test objects which includes generating expansion inducing energy focused upon the test object at a first location, thereby causing pressure wave within the test object. At a second location, the acoustic waves are detected and the resonant frequencies' quality factors are calculated and compared to predetermined quality factor data. The inventors claim that such comparison provides information of whether the test object contains a defect. Once again, the method operates with a single rejection parameter, which, when applied to wafers, limits its ability to distinguish cracked samples from statistically variable samples, leading, therefore to high proportion of false positive event unacceptable in manufacturing practice. Further the method requires high precision in locating an incoming acoustic pulse (impact) and of a sensor detecting acoustic waves. This precludes identification of cracks located in proximity to the selected positions. Crucially, an impact testing by a single or multiple acoustic pulses is less sensitive than techniques based on periodical sinusoidal excitation. The periodic excitation allows for substantial reduction of signal-to-noise ratio by synchronizing frequency and phase of a detected response to an excitation with that of a reference signal causing the excitation. Furthermore, the impact testing has high probability to creating new cracks in standard silicon wafers when focused ultrasonic beam hit the wafer close to areas of high internal stress. It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. Therefore, the present invention addresses the need for fast, accurate and non-destructive determination of mechanical defects in wafers, including detecting and locating cracks in wafers, particularly applicable as a diagnostic in-line tool in solar cell production. SUMMARY OF THE INVENTION The invention provides a method and apparatus for in-line detection and location of cracks in a thin wafer by exciting multiple mechanical vibrations in the wafer and measuring the response of the wafer at certain selected locations. In its broadest aspect the present invention presents a method for in-line mechanical quality control of wafers, said method comprises the steps of: coupling a wafer with a broad-band actuator, providing at least one acoustic sensor adapted for measuring vibrations at selected locations on the wafer, measuring multiple resonant frequency curves by sweeping frequency of the broad-band actuator simultaneously in predetermined frequency intervals and recording the wafer's resonance vibrations using the acoustic sensor; comparing the measured resonant frequency curves with reference resonant frequency curves, generating a rejection signal if the deviation between measured and reference resonant frequency curves exceeds a defined set of values, and decoupling the wafer and the actuator. In a preferred embodiment a resonance frequency, an amplitude and a bandwidth of each of the resonant curves are each compared with that of a reference resonance frequency curves. In one embodiment according to this aspect of the invention, the method for in-line mechanical quality control of wafers is calibrated using a standard wafer. The standard wafer is carefully selected to be mechanically sound and crack free. The standard wafer is typically inspected using a range of the characterization methods known in the art, but not necessarily suitable for the requirements of fast in-line quality control. The calibration of the method for in-line control of wafers includes the steps of: Recording of a full range acoustic frequency spectrum of the reference wafer; Analysis of the spectrum, identification of resonance peaks and selection of those peaks that are sensitive for cracks and other mechanical defects that can cause the breakage of a wafer; Selection of the required number and positions of the sensors, depending on the quality requirements of the manufacturing process that is to be controlled. While we found that in most cases two separate sensors provide sufficient data, it is appreciated that the tougher the requirements for quality the larger the number of sensors required; Including a quality table of acceptable deviations into the defined set of values. It is preferable to use a plurality of standard wafers to record statistical variations of the reference resonant curves caused by the factors not leading to breakage during high throughput manufacturing process. Such factors include, for example, small variations in lateral dimensions of wafer, its thickness, and shape. In some cases some small cracks are considered acceptable, especially when these cracks are located in non-critical parts of wafers. Therefore, it is preferable that plurality of standard wafers is selected to be representative in respect to a full batch excluding, of course, cracks that lead to the mechanical breakage. During the calibration each of the standard wafers is subjected to the same procedural steps as the tested wafer during in-line testing within a continuous manufacturing process. This excludes the step of comparing the resonant frequency curves and the step of generating the rejection signal. In one embodiment, the statistical analysis of the reference resonant frequency curves comprises determination of statistical parameters listed in the following table. TABLE 1 Statistical parameters of reference resonant frequency curves. Frequency of a resonance  Amplitude  Bandwidth A parameter of resonance f i A i BW i curve of the i-th frequency interval Corresponding mean value f i Ā i BW i determined from the standard frequency curves Standard deviation of the σ i f σ i A σ i BW mean value Sensitivity factor n i f n i A n i BW In a preferred embodiment each of the multiple resonant frequency curves is analyzed to compute the parameters shown in the first raw of the table. The rejection signal is generated when the following conditions are simultaneously satisfied: | f i − f l |>n i f σ i f | A i −Ā l |>n i A σ i A | BW i − BW l |>n i BW σ i BW The coefficients n i are chosen in accordance with a selected detection limit and with an acceptable number of false rejections. It is appreciated that the lower the detection limit the higher the number of false rejects. The invention provides for adjusting the coefficients n i depending on specific requirements of a particular manufacturing process. The detection limit is preferably the minimum size of a crack which, if detected in a wafer, causes generation of the rejection signal. In a further embodiment, prior to coupling with the actuator and after completion of the measurements, the wafer progresses through a manufacturing line; the manufacturing line usually comprises a number of manufacturing processes. In a typical arrangement, the manufacturing line includes a movable platform, conveyer belt, pick-and-place mechanisms or any other transportation means used in such continuous manufacturing processes, and the wafer is engaged with the transportation means. The wafer coupled with the actuator is preferably disengaged from the transportation means. In a still further embodiment the coupling and decoupling the wafer and the actuator is synchronized with the operation of the transportation means. It is essential to achieve an in-line integration of the quality testing procedure. In one example, the transportation means remain motionless during the recording of the resonant frequency curves. In another example, the movement of the transportation means just slows down. It is preferable that when the recording and analysis of the resonant frequency curve is completed and the wafer is about to be decoupled from the actuator, the next subsequent wafer is in proximity to the actuator, so that the in-line quality control procedure can be applied to the next wafer without undue delay. In a yet further embodiment the coupling of the wafer and the actuator is achieved by a high speed electronically controlled coupling means such as electrostatic chuck, utilizing electrostatic attraction, magnetic coupling, injecting a coupling fluid, or any other coupling means known in the art of acoustic measurements. In a preferred arrangement the coupling means is an electronically controlled vacuum switch creating a vacuum in the space between the wafer and the actuator so that the wafer is coupled with the actuator by action of vacuum force. Typically the actuator comprises a piezoelectric generator of acoustic wave and a body on which the generator is mounted. The invention provides for an arrangement where the wafer coupled with the actuator is mechanically supported by the actuator during the measurement of the resonant frequency curves. In one realization the wafer rests on the actuator. In another arrangement the wafer is suspended beneath the actuator. In another embodiment, the rejection signal initiates transferring of the wafer to the separating means. In the absence of the rejection signal the accepted wafer is either returned to the transportation means, from which it was disengaged prior to the measurements or is moved to another transportation means. In both cases the transportation means transfer the wafer through stages of a manufacturing process. If, however, the wafer was determined to be not suitable for further stages of manufacture, it is transferred to the separation means. Similarly to the transportation means, the separation means may comprise a conveyer belt, a pick-and-place mechanism, movable platform, or even a stack or a cassette where the rejected wafers are collected. To minimize false positive decisions when an acceptable wafer is mistakenly transferred to the separation means, the invention provides for an additional step of inspecting the rejected wafer. It is appreciated that only a small proportion of the wafers will be rejected and, therefore, the step of inspecting the rejected wafer does not need to satisfy stringent requirements of in-line procedures, such as fast handling and short duration of time intervals required for collection and processing of data. The inspection of the rejected wafer preferably comprises an imaging technique, such as, for example, luminescence. In a still another embodiment, if the inspection of the rejected wafer determines that the reject signal was false, the wafer is returned to the transportation means and the statistical parameters, including the defined set of values, are adjusted to accommodate the new reference information. In a yet another embodiment vibrations of the wafer are simultaneously detected in at least two differing selected positions of the wafer by at least two separate acoustic sensors. The sensors may be in a contact with the wafer at selected locations or alternatively may be placed proximate the selected positions. In the latter case the wafer's vibrations can be detected by one of the known means including, for example, monitoring the position or the direction of a reflected laser beam. It is preferable to choose the selected positions on the wafer's periphery. In some cases, in particular, when a decision to accept/reject the wafer is on the boundary of accept/reject conditions the method may include relocating the sensors to new selected positions and repeating the measurements of the resonant frequency curves. From another aspect, the invention provides an apparatus for in-line quality control of wafers comprising: A broad band acoustic actuator capable of exciting mechanical vibrations in a wafer simultaneously in the predetermined frequency ranges. At least one acoustic sensor capable for detecting mechanical vibrations in the wafer and converting the vibrations into electrical signals At least two electrical generators jointly delivering the superposition of the electrical signals to the acoustic actuator At least two electrical amplifiers each synchronized with the corresponding electrical generator and tuned to measure the vibrations of the wafer in one of the predetermined frequency ranges Data acquisition and control system and A means for fast coupling the wafer with the actuator. In one embodiment, the apparatus further comprises a transportation means for transferring the wafer prior to coupling the wafer and the actuator. The transportation means is preferably adapted to disengage the wafer for the measurement of the resonant frequency curves. In another embodiment, the data acquisition and control system is adapted to synchronize the transportation means with the means for fast coupling the wafer and the actuator. In yet another embodiment, the apparatus further includes a means for positioning the sensors at the selected locations of the wafer. In a further embodiment, the apparatus further includes the means for fast coupling the wafer and the actuator. The means for fast coupling the wafer and the actuator preferably comprises a fast electronically controlled vacuum switch, so that the wafer is mechanically coupled with the actuator by the action of a pressure differential created between the outer side of the wafer facing the atmosphere, and the inner side facing the actuator. In one realization, the pressure differential is applied to the wafer through a small hole created in the actuator. After the resonant frequency curves are detected, the wafer may be uncoupled from the actuator and returned to the manufacturing line. This is commonly achieved by returning the wafer to the transportation means. However, if the wafer fails quality requirements and is found to be not suitable for further manufacturing steps, the wafer may be removed from the processing line and, for example, placed in the separation means designated for reworking or disposal. In an alternative arrangement, the wafer is in a stack of wafers and is taken from the stack for coupling with the actuator. If the wafer complies with the quality requirements it may be returned to the original stack, placed into another stack or transferred onto the transportation means. If, however, the wafer fails the quality requirements, it may be, for example, transferred to a container or yet another stack designated for reworking or disposal. Based on the decision on the quality of the wafer an electrical signal may be generated to either keep the wafer within the manufacturing line or to remove the wafer from the manufacturing line. BRIEF DESCRIPTION OF THE DRAWINGS Other advantages of the present invention will be readily appreciated as it becomes better understood by referring to the following detailed description when considering the accompanying drawings wherein: FIG. 1 is a diagram showing a method for quality control of wafers according to the first example of the invention. FIG. 2 is a diagrammatic cross-sectional representation of an apparatus for in-line mechanical quality control of wafers according to the second example of the invention. FIG. 3 is a diagrammatic top-view representation of a device for in-line mechanical quality control of wafers according to the third example of the invention. FIG. 4 is a full range ultrasonic frequency spectrum obtained on a crack-free reference wafer, showing four individual vibration modes A, B, C and D according to the fourth example of the invention. FIG. 5 is a comparison of the resonance frequency curves on the reference wafer and the wafer with a crack according to the fifth example of the invention. FIG. 6 is a dependence of peak-shift, at selected frequencies, on the size of a crack according to the sixth example of the invention. FIG. 7 demonstrates the effect on the position, shape and amplitude of the resonance peaks by cracks in a wafer according to the seventh example of the invention. FIG. 8 demonstrates commonly used shapes of wafers and corresponding shapes of the actuators according to the eights example of the invention. FIG. 9 is a diagrammatic representation of a four-sensor apparatus according to the 9 th example of the invention. FIG. 10 depicts resonance peaks obtained from measurements made at the four sides of a square wafer according to the 10 th example of the invention. FIG. 11 is a flow-chart diagram of a method for quality control of wafer according to the 11 th example of the invention. FIG. 12 is a flow-chart diagram of a calibration procedure according to the 12 th example of the invention. FIG. 13 is a histogram demonstrating a statistical distribution of bandwidths of a set of 282 125×125 mm wafers according to the 13 th example of the invention. FIG. 14 depicts normal distribution of resonance frequency (a), bandwidth (b) and amplitude (c) according to the 14 th example of the invention. FIG. 15 demonstrates a statistical analysis performed on a set of 125 mm Si solar cell. DETAILED DESCRIPTION OF THE INVENTION The chosen first example of the invention, shown in FIG. 1 includes a generator subsystems 4 comprising a number of generators X 1 , X 2 , . . . XN, Y 1 , Y 2 . . . YK, each tuned to a certain frequency range and each controlled by a data acquisition and control subsystem. Each of the generators is synchronized with a corresponding amplifier either from a subsystem 4 X connected to a sensor 12 X, which detects vibrations of a wafer 10 in the X-direction, or from a subsystem 4 Y, connected to a sensor 12 Y, which detects vibrations of the wafer 10 in the Y-direction. It is common for the predetermined frequency range of X-generators to be similar or even identical to that of the analogues Y-generators, such that the generators X 1 and Y 1 may operate in the same range of frequencies. However, each of the X-generators operates in a different frequency range. The number of generators depends on the number of resonance peaks to be recorded. The number N of X-generators is not necessarily the same as the number K of Y-generators. The generators 4 are electrically connected to an actuator 11 that is acoustically coupled to a wafer 10 . The actuator and the sensors are typically piezoelectric devices. The actuator is a linear device, so that a superposition (linear combination) of independent electrical signals generated by X- and Y-generators is converted by the actuator to a superposition (linear combination) of acoustic vibrations at frequencies identical to frequencies of the independent electrical signals superimposed by the actuator. In operation, a data acquisition and control subsystem 5 effects the generators 4 to sweep the frequency of generated electrical voltage in a range predetermined for each generator. This causes the actuator 11 to vibrate according to a superposition of signals created by the generators. The actuator 11 , in turn, causes ultrasonic vibrations in the wafer 10 . The vibrations are measured by the sensors 12 X and 12 Y and further amplified by the amplifiers 4 X and 4 Y for acquisition by the data acquisition and control subsystem 5 . In this way, individual frequency sweeps from each generator are transferred to corresponding vibration modes of the wafer and these vibration modes are recorded independently from each other and simultaneously by the sensors 12 X and 12 Y. An apparatus for in-line mechanical quality control of wafers of the second example, shown schematically in FIG. 2 , comprises a vacuum holder 21 ; a piezoelectric actuator 25 , supported by the vacuum holder 21 and acoustically coupled to a wafer 20 ; a sensor 22 , also acoustically coupled to the periphery of the wafer 20 ; a vacuum pump 24 ; an electronically controlled vacuum switch 23 ; and an electronic block 26 , that includes a generator, an amplifier, and a data acquisition and control subsystem. The actuator 25 has a small central hole allowing a reliable vacuum coupling between the wafer and the actuator by applying small (about 50 kPa) negative pressure to the back side of the wafer. In operation, the vacuum pump 24 is switched on permanently and the vacuum switch 23 is initially in the closed position. When the wafer 20 is positioned on the actuator 25 the electronic block opens the vacuum switch 23 and the negative pressure created at the back side of the wafer 20 ensures coupling of the wafer 20 and the actuator 25 . The sensor 22 approaches the wafer 20 and contacts the wafer's edge at a selected location. The electronic block immediately commences sweeping frequency simultaneously at a number of predetermined frequency ranges. The actuator 25 vibrates causing ultrasonic vibrations in the wafer 20 ; the sensor 22 converts these vibrations into electrical voltage that is in turn amplified, acquired and analyzed by the electronic block 26 . By comparing the measured resonant frequency curves with reference resonant frequency curves the electronic block 26 makes a rejection-acceptance decision. When the measurements are completed, the electronic block 26 closes the vacuum switch 23 ; the wafer 20 can now be removed from the apparatus and depending on the rejection-acceptance decision either returned to the conveyer line for further processing or placed aside for reworking or disposal. In a preferred arrangement, the wafer is on a transportation means, typically—on a conveyer belt (not shown), prior to coupling the wafer and the actuator. The transportation means may stop for a short time required for the measurement. Typically the transportation means has an opening and the wafer is transported in such a way that the opening is below and close to the centre of the wafer. The vacuum holder 21 supporting the actuator 25 is attached to a Z-stage (not shown) positioned bellow the transportation means. The Z-stage moves the vacuum holder 21 upwards until the actuator is in contact with the wafer. This is followed by opening the vacuum switch 23 to provide a pressure differential sufficient for acoustic coupling the actuator and the wafer. Optionally the Z-stage may further raise the vacuum holder 21 such that the wafer mechanically supported by the actuator is raised above the conveyer belt. The sensor 22 is now in contact with the wafer's edge. When the measurements are completed, the data acquisition and control system switches the vacuum switch off; this removes the pressure differential and decouples the wafer 20 and the actuator 25 . Prior to that the system may cause the Z-stage to lower the wafer back to the conveyer belt. The vacuum holder 21 is then transferred to its position below the transportation means while the wafer 20 is returned to the transportation means. If, however, the rejection signal is generated, the wafer may be removed from the transportation means sideways. The transportation means recommences its movement until the next wafer is brought to a measurement position above the vacuum holder. The transportation means stops at this position and the measurements are now repeated with another wafer. In this way the in-line mechanical quality control of wafers is conducted. A horizontal double-sided arrow in FIG. 2 shows directions of movement of the sensor 22 towards (before measurements) and away from (after measurements) the wafer 20 , whereas a vertical double sided arrow shows the directions of movement of the actuator 25 , attached to the vacuum holder 21 , upwards towards the wafer 20 and then upwards with the wafer 20 (before the measurements); and downwards with the wafer 20 , and, after the wafer 20 rests on the transportation means, further downwards bellow the transportation means (after the measurements). An apparatus of the third example of the invention is shown in FIG. 3 . A wafer 30 is shown in 3 separate positions: before the test ( 30 a ), during the test ( 30 b ), and after the test ( 30 c ). The wafer is transported by a conveyer belt 34 . During the test the wafer enters the measuring unit 37 , where it is acoustically coupled with an actuator 31 and a sensor 32 . After completion of the test the wafer 30 is returned to the conveyer belt 34 . FIG. 4 is a calibration frequency scan recorded on a crack-free standard wafer in the frequency range from 20 to 93 kHz. As shown, four separate resonance peaks, labeled as A, B, C and D, are recorded and selected for in-line mechanical quality control of wafers. FIG. 5 shows experimental verification of the invention. Two identical in size and shape 125 mm×125 mm square shaped single-crystal silicon wafers were tested. One of these wafers is a standard wafer (closed marks), having no mechanical or structural defects such as cracks, that was confirmed by Scanning Acoustic Microscopy imaging with 10 microns resolution. The second wafer (open marks) has a 3 mm peripheral crack introduced at the center of the wafer's edge. The effect of the crack is clearly observed as a downward frequency shift, reduction of the peak amplitude and increased peak bandwidth (peak broadening). FIG. 6 demonstrates that in-line mechanical quality control of wafers is capable for detecting dimensions of cracks in a wafer and distinguishing between cracks at the centre of the wafer edge and that at its corner. In this example peak shifts (difference between the measured resonance frequency and the reference resonant frequency) measured at three different resonances (at 40 kHz, 58 kHz and 86 kHz) are presented as functions of the length of a crack. The example demonstrates that 86 kHz resonance is preferable for the detection of cracks close to the centre of the wafer's edge, whereas 58 kHz is more suitable for the detection of cracks positioned in the proximity of the wafer's corners. At least two separate resonances are therefore required to indicate the position of a crack on a wafer edge. An example of FIG. 7 shows resonance peaks recorded for a standard wafer (closed marks) and a cracked wafer (open marks). A resonance at around 56.3 kHz is shown in FIG. 7 a , and at around 87.6 kHz—in FIG. 7 b . A 6 mm crack positioned closed to the centre of the wafer's edge resulted in a small 18 Hz frequency shift at the 56.3 kHz resonance, and in a substantial 600 Hz downward frequency shift at the 87.6 kHz resonance. The method for in-line mechanical quality control of wafers would reject this wafer from further processing. Three different examples of actuators are shown in the FIG. 8 . An arrangement when the shape of a transducer is similar to the shape of a wafer usually results in better acoustic matching and is preferred. A circular actuator is preferable for use with a circular wafer ( FIG. 8 a), a square actuator—with a square wafer ( FIG. 8 b ) and a rectangular actuator—with a rectangular wafer ( FIG. 8 c ). FIG. 8 also demonstrates that in a preferable arrangement a transducer is coupled to the geometrical centre of a wafer. Yet another example of the invention is shown diagrammatically in FIG. 9 . An apparatus of this example comprises four sensors 82 , each adapted to measure mechanical vibration of a square wafer 30 at approximately the centre of each side of the square. The sensor 82 N measures at the north side of the wafer, sensor 82 S—at the south side and so on. An actuator 81 , acoustically coupled to the wafer 80 , is controlled by an electronic block 86 . The electronic block 86 is adapted to sweep frequency in two independent intervals and to collect resonant frequency curves from four separate sensors. Therefore, the block 86 comprises two generators and two groups of amplifiers (four amplifiers in each group). Each amplifier from the first group is synchronized with the first generator to measure the first vibration resonance and, similarly, each amplifier from the second group is synchronized with the second generator to measure the second resonance. In operation, the first and the second generators sweep the frequency around the first and the second resonance peaks correspondingly, causing vibration of the actuator, which in turn excites vibrations of the wafer. If the wafer is free of defects, the resonance peaks detected at each of N, S, W, E sides of the wafer are identical at each of the preselected resonances. If, however, one of the sides contains defects the resonance peak measured at that side may deviate from those measured at the other three sides of the wafer. FIG. 10 shows data obtained experimentally by measuring two vibration resonances at each of four sides (N, S, W, E) of a 125 mm×125 mm square wafer. In FIG. 10 ( a ) a resonance peak at 36 kHz is measured at the centers of four different sides (East, North, South and West) of the wafer. All four resonance peaks have close values of amplitude, peak position and bandwidth. In FIG. 10 ( b ) the same measurements were repeated at a different resonance peak of 88.6 kHz. Evidently, in this case the amplitude and shape of signals are quite different. The South side has the smallest resonance peak amplitude due to mechanical defects on this side. Therefore, method and apparatus of the invention allow not only to detect the presence of mechanical defects in a wafer, but also to determine their geometrical location. FIG. 11 and FIG. 12 depict flow-chart diagrams and include procedures typically implemented in the invention. With respect to FIG. 13 the histogram depicts statistical distribution of bandwidth of measured resonant frequency curves of a set of identical as-cut 286 cast wafers selected from a single batch. The distribution is approximated by Gaussian curve and has the following parameters: mean value−90.4 Hz, standard deviation−33 Hz. The wafers with bandwidth outside 3σ interval around the mean value were rejected FIG. 14 shows a normal distribution of one of rejection parameters of the method, i.e. the resonance frequency, the amplitude of the bandwidth on a set of standard wafers. Internal part of the normal distribution is less than one standard deviation (σ) from the mean (μ). For the normal distribution, this account for 68.2% of entire set of wafers, while two standard deviations (2σ) from the mean value account for 95.4% and three standard deviations account for 99.6%. FIG. 15 demonstrates an importance of the simultaneous application of rejection criteria. Only cells which fall outside 3σ—thresholds for at least 2 of 3 rejection criterion were considered rejects. These cells (#2, 26, 43, 54 and 62) were independently measured using a Scanning Acoustic Microscope, which revealed cracks in the range of lengths from 3 mm to 50 mm. The invention has been described in an illustrative manner and it is to be understood that the terminology that has been used is intended to be in the nature of words of description rather than of limitation. It is now apparent to those skilled in the art that many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that the invention may be practiced otherwise than as specifically described.
An apparatus and a method are disclosed for testing the quality of a wafer. The apparatus and a method comprise coupling a broad-band actuator to the wafer. Sweeping frequencies are connected to the broad-band actuator for vibrating the wafer. An acoustic sensor is coupled to the wafer for measuring a resonant frequency of the vibrating wafer. The measured resonant frequency of the vibrating wafer is compared with a reference resonant frequency to deterring the quality of the wafer.
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RELATED APPLICATIONS The present application is related to U.S. Provisional Patent Application Ser. No. 60/915,904, filed on May 3, 2007, which is incorporated herein by reference and to which priority is claimed pursuant to 35 USC 119. BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a method for shaping glass on a microscopic scale utilizing self-inflation. 2. Description of the Prior Art Glass blowing is an art that dates back over 2000 years. Today, glass blowing is used in a wide array of applications, including scientific glassware, optical components, consumer glass containers, and visual arts. Although blow-molding techniques are used in the glass industry to automate the fabrication of bottles and other containers, many fine glass products are still shaped one at a time by glass blowers. The property that enables the successful shaping of glass is that its viscosity is highly dependent on the temperature. In order to shape glass it needs to be heated above its softening point, i.e., the temperature at which glass has a viscosity of 10 6.6 Pascal-seconds (Pa-s) (about 800° C. for borosilicate glass). In conventional glass blowing, a gob of glass is first heated inside a furnace. The gob is then removed from the furnace and blown into desired shapes. Often the heating and blowing steps are repeated multiple times. Once the glass is shaped, it is usually annealed to remove stresses that developed during the blowing. The original implementation of micro-glass blowing was a direct adaptation of conventional glass blowing techniques on a microscale, i.e., to bond a glass wafer to a through-etched silicon wafer, heat the bonded wafers, and directly apply fluidic pressure through the etched holes in order to blow spheres—described in US Patent Application Publication 2007/0071922. Microspheres have been fabricated in the past using different fabrication methods. For example, see: R. Cook, “Creating Microsphere Targets for Inertial Confinement Fusion Experiments”, Energy & Technology Review, pp. 1-9, April 1995; R. Dagani, “Microspheres Play Role in Medical, Sensor, Energy, Space Technologies”, Chemical and Engineering News, pp. 33-35, December 1994. However, previously fabricated microspheres are not attached to a substrate and can only be filled with certain light gases (e.g. hydrogen) through diffusion. BRIEF SUMMARY OF THE INVENTION Glass blowing techniques can normally only be used on a macroscopic scale, and the glass products have to be shaped one at a time. We here disclose and demonstrate how multiple micro-glass-spheres can be formed simultaneously on a silicon substrate. A thin sheet of glass is first bonded to an etched wafer. The sample is then heated inside a furnace above the softening point of glass, and due to the expansion of the trapped gas the glass is blown into spherical shapes. Other alternative ways of shaping the glass are also included with the scope and spirit of the invention. The capability to blow glass on a wafer level enables several applications, e.g. micro-lenses and small gas confinement chambers. Potentially this technology can also be used for drug delivery and diagnostic devices, as well as other biomedical applications. It must be understood that the term “wafer” is or can be used interchangeably with the term “chip” throughout this specification as appropriate. In general, a wafer may include a multiplicity of chips or be diced into separate chips. A chip may also include a plurality of spheres and need not be a considered as restricted to carrying a single sphere or micro-object included on it. Additionally, while spherical shapes are considered for illustrative purposes, non-spherical shapes can also be fabricated by applying blowmolding techniques. Furthermore, cylindrical (in-plane) micro-glass channels can be achieved by defining narrow etched trenches in the silicon wafer. Thus, the illustrated embodiment is particularly directed to glass blowing on a microscopic level, glass blowing compatible with microfabrication technologies, glass blowing on a wafer level, a method for fabricating microspheres or other micro-glass shapes, simultaneous manufacturing of numerous micro-structures on a chip, an ability to simultaneously fill multiple glass shells with gases and other substances This disclosure introduces fabrication processes where glass is blown on a wafer level allowing thousands of glass parts to be built simultaneously. The presented micro glass blowing also opens opportunities for integration with electrical and mechanical components on a chip using conventional microfabrication techniques. The illustrated embodiment of the fabrication process was developed for a micromachined implementation of a nuclear magnetic resonance gyroscope (NMRG), where a spherical gas confinement chamber is preferred in order to minimize the self-magnetization of the atoms. Although no previous micro-NMRGs have been reported, large NMRGs built around traditionally blown glass spheres have been demonstrated in the past. Many other novel applications may be enabled by this new fabrication technique, including microscopic spherical gas confinement chambers, complex three-dimensional microfluidic networks for gas analyzers or miniature drug delivery systems, spacers and hermetic enclosures for wafer-level packaging, micro discharge lamps and plasma light sources, and micro-optical components (e.g. mass-produced microscopic glass lenses). The illustrated embodiments thus include a method for glass-blowing on a microscopic level comprising the steps of defining a plurality of blind microholes in a wafer; disposing a sheet of thermally formable material onto the wafer covering the microholes to trap a gas in the microholes; heating the sheet of thermally formable material until a predetermined degree of plasticity is achieved; applying thermally generated pressure arising from the thermal expansion of the trapped gas in the microholes to the sheet of thermally formable material, while the sheet of glass is plastic; and simultaneously forming a plurality of blown micro-objects in the sheet on the wafer by means of continued application of thermally generated pressure for a predetermined time. The step of defining the microholes comprises etching the microholes using deep-reactive ion etching (DRIE). However, it must be understood that the microholes may be made using any methodology now known or later devised, such as etching by either wet or dry etchants, micromechanical drilling, laser etching, microelectromachining and the like. The step of defining the microholes comprises etching the microholes using wet etchants. The step of defining the microholes comprises etching the microholes using any currently known or future discovered means of etching. The step of disposing a sheet of thermally formable material comprises bonding the thermally formable material to the wafer using anodic bonding to seal the plurality of microholes. The step of disposing a sheet of thermally formable material comprises bonding the thermally formable material to the wafer using any bonding methods currently known or future discovered. The step of disposing a sheet of thermally formable material comprises bonding borosilicate glass to the wafer. The step of disposing a sheet of thermally formable material comprises bonding the thermally formable material inside a controlled pressure environment so that the volume of the corresponding micro-object formed by the thermally generated pressure can be accurately controlled. The illustrated embodiments of the method further comprises the step of fabricating integrated electrical and mechanical components on or into the wafer. The illustrated embodiments of the method further comprises the step of disposing a gas-source material in a solid state in the micro-objects and heating the gas-source material to produce a vapor inside the micro-objects. The illustrated embodiments of the method further comprises the step of sealing the micro-objects by bonding a layer to the backside of the wafer. The step of simultaneously forming a plurality of blown micro-objects in the sheet on the wafer by means of continued application of pressure for a predetermined time comprises blowmolding the micro-objects into a mold. The step of simultaneously forming a plurality of blown micro-objects in the sheet on the wafer by means of continued application of pressure for a predetermined time comprises controlling the pressure of the surrounding environment so that the volume of the corresponding micro-object formed by the thermally generated pressure can be accurately controlled. The step of simultaneously forming a plurality of blown micro-objects in the sheet on the wafer by means of continued application of pressure for a predetermined time comprises forming a hollow substantially spherical micro-object or hemispherical micro-object. The step of simultaneously forming a plurality of blown micro-objects in the sheet on the wafer by means of continued application of pressure for a predetermined time comprises forming hollow substantially cylindrical micro-channels. The step of defining the plurality of blind microholes into the wafer further comprises defining an enlarged volume chamber within each blind microhole so that the corresponding micro-object formed by the thermally generated pressure is increased in volume as compared to the micro-object formed by the thermally generated pressure in the corresponding microhole without the enlarged chamber formed therein. Each microhole has an opening adjacent to the sheet communicating with an interior of the micro-object when the micro-object is formed. The opening has a reduced diameter r 0 compared to remaining portions of the microhole such that sphericity of the micro-object formed in the sheet as determined by the ratio of the height of the micro-object to its radius tends toward 1. The reduced diameter opening is of the order of a few microns. In one embodiment the wafer is comprised of two layers bonded together, namely a top layer having the microholes defined therethrough with the reduced diameter opening and a bottom layer having blind microholes defined therein with a larger diameter than the opening aligned with the microholes in the top layer, and where disposing the sheet of thermally formable material onto the wafer covering the microholes to trap a gas in the microholes comprises disposing the sheet of thermally formable material onto the top layer. The illustrated embodiment includes an apparatus in which some of the foregoing embodiments of the method is practiced. The illustrated embodiment further includes the fabricated micro-objects which are made from some of the foregoing embodiments of the method. While the apparatus and method has or will be described for the sake of grammatical fluidity with functional explanations, it is to be expressly understood that the claims, unless expressly formulated under 35 USC 112, are not to be construed as necessarily limited in any way by the construction of “means” or “steps” limitations, but are to be accorded the full scope of the meaning and equivalents of the definition provided by the claims under the judicial doctrine of equivalents, and in the case where the claims are expressly formulated under 35 USC 112 are to be accorded full statutory equivalents under 35 USC 112. The invention can be better visualized by turning now to the following drawings wherein like elements are referenced by like numerals. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 a - 1 e is a diagram of the steps of a method wherein micro-objects are made without the assistance of external blowing or pressure, but are thermally self-inflated or blown. FIGS. 2 a - 2 d is a diagram of the steps of a method to fabricate micro-objects in which larger or highly spherical shapes can be made. FIG. 3 is a cross-sectional diagram of a substantially hemispherical micro-object fabricated with a wafer according to the invention. FIGS. 4 a - 4 h is a diagram of the steps of a method wherein micro-objects are thermally self-inflated or blown and then later filled with an alkali, gas and/or other substance. FIG. 5 is a graph of the estimated height of a blown structure or micro-object, as a function of the radius of the undeformed membrane, r 0 . FIG. 6 is a graph of the estimated sphericity of a blown structure or micro-object, i.e., the ratio between the height and the diameter of the hollow semisphere, as a function of the radius of the undeformed membrane, r 0 . FIG. 7 is a diagram of an embodiment wherein two wafers are employed to fabricate a substantially spherical micro-object with a size and volume that can be defined independently of the radius of the undeformed membrane, r 0 . FIG. 8 is a graph of microsphere estimated height verse estimated blow up time required to blow uniformly heated hollow glass semispheres at 850° C. FIG. 9 is a diagram illustrating the variables which parameterize wall thickness thinning in a microsphere. FIG. 10 is a microphotograph of a microsphere fabricated according to the invention with scanning electron microscope insets showing wall thickness and structure in two locations with are included with solid outlined boxes. The invention and its various embodiments can now be better understood by turning to the following detailed description of the preferred embodiments which are presented as illustrated examples of the invention defined in the claims. It is expressly understood that the invention as defined by the claims may be broader than the illustrated embodiments described below. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The illustrated embodiments of the invention disclosed below provide a way of simultaneously forming multiple microscopic glass components on a wafer. These glass-structures are orders of magnitude smaller than what can be achieved using traditional glass blowing techniques. In the illustrated embodiment, the glass spheres are attached to a wafer, allowing for integration with traditional micro-fabrication techniques. Furthermore, the glass structures can be filled with gaseous, liquid, and/or solid materials post fabrication. The illustrated embodiment of the invention satisfies the need to implement a microscopic gas confinement chamber. Many specific applications for such a chamber can be considered, e.g. nuclear magnetic resonance gyroscopes, microlamps, and hydrogen capsules for H-vehicles. Other possible applications include micro-lenses, optical switches, laser fusion targets, magnetic shielding when a shielding material is applied on the inside/outside of the sphere, as well as lab-on-a-chip, drug delivery systems, medication capsules, and other biomedical devices. In the preferred fabrication process as depicted in FIGS. 1 a - 1 e a silicon wafer 10 is first patterned with a layer of AZ4620 photoresist 12 . Cylindrical cavities 14 are then etched in the wafer using deep-reactive ion etching (DRIE). The photoresist 12 is removed with acetone and a thin sheet of borosilicate glass 16 (e.g. Pyrex 7740) is anodically bonded to the top surface of wafer 10 , covering the openings to etched cavities 14 . Once bonded, the glass 16 may also be ground and polished if thinner cross sections or particular surface finishes are desired. Next the glass covered wafer 10 of FIG. 1 d is placed inside a furnace at a temperature above the softening point of the glass 16 . Since the pressure inside the sealed cavities 14 increases when the wafer 10 is heated, the glass 16 will deform into spherical shapes 18 , as illustrated in FIG. 1 e. Once the glass 16 is shaped, the backside 20 of the wafer 10 can be etched as shown in FIG. 4 e described below to allow for filling of various gases or other substances into spheres 18 . The backside 20 can then be resealed using conventional wafer bonding techniques. Etching of the backside 20 is also necessary if the process is used for creating micro-lenses, although the backside would naturally not be resealed in this case since an optical path would be needed between the two sides of the lens. The fabrication method illustrated in FIGS. 1 a - 1 d constitute the foundation of the micro glass blowing process and define the shape and size of the glass structures 18 . While these steps are usually included in the fabrication process, additional steps can be added as needed to suit a particular application. For many applications, e.g. micro-lenses and gas confinement chambers, it is necessary to etch the backside of the silicon wafer 10 after the glass spheres 18 have been formed. For example, FIGS. 4 a - 4 h illustrate how a gas confinement chamber can be fabricated by etching the backside of the silicon wafer 10 in order to be able to fill the glass sphere 18 with an alkali metal and/or buffer gas. The steps illustrated in FIGS. 4 a - 4 c are the same as those in FIGS. 1 c - 1 e respectively (the steps in 1 a - 1 b were omitted from this illustration, but would be included in the actual fabrication). In the step illustrated in FIG. 4 d , the wafer 10 is placed in a temporary holder 22 in order to protect the glass spheres 18 . The backside 20 is then patterned and etched in the step FIG. 4 e , using for example DRIE. For illustrative purposes, a filling technique similar to that described in S. Knappe, et al., Opt. Lett. 30 (2005) 2351-2353 is used. It is to be understood that any filing technique now known or later devised could be substituted. BaN 6 and 87 RbCl are placed inside a small glass ampoule 24 with a 5 mm long nozzle 26 of 700 μm diameter. The wafer 10 with the glass-blown cell or sphere 18 is placed inside a vacuum chamber and the ampoule 24 is aligned with the opening 14 . Next, the ampoule 24 is heated in order to react the compounds, as shown in the step FIG. 4 f of the fabrication process. Since the vapor pressure of rubidium is higher than that of Ba and Cl, a fairly pure beam of 87 Rb emerges from the ampoule 24 and is deposited into the sphere 18 . The nitrogen produced during the reaction is pumped away. The vacuum chamber inside which the filling is performed (not shown) is then filled with the desired combination of buffer gases, here a mixture consisting of Xe in natural isotopic abundance and N 2 . The backside 20 is then sealed by anodic bonding of a glass wafer or sheet 28 in the step of FIG. 4 g . Finally, the wafer 10 is taken out from the vacuum chamber and the temporary holder 22 is removed from the wafer 10 as shown in the step of FIG. 4 h . The materials used to fill sphere 18 have been described here only for the purposes of illustration and it is to be expressly understood that any materials and gases may be substituted as desired. One alternative option is to fill the cavities 14 with the desired substances before the glass 16 is bonded in the step of FIG. 1 d (or FIG. 4 b ). If this is done, the etch, filling, and resealing steps in FIGS. 4 d - 4 g would not be required. However, certain light gases may diffuse through the glass 16 when the glass covered wafer 10 is heated inside a furnace. Furthermore, some substances may vaporize and Increase the pressure Inside the etched cavity 14 more than desired. For certain substances, an additional filling step (before the step of FIG. 1 d ) is a preferred option instead of filling cavities 14 and spheres 18 from the back with substances post-fabrication. Another embodiment of the process is to etch non-cylindrical cavities in the wafer. For example, if a trench of substantial length (not shown) is etched in the wafer and the thermally formable material is subsequently bonded and shaped by the thermally generated pressure, the micro-structure 18 ′ would assume the shape of a cylindrical channel with its axial direction parallel to the wafer plane (or out-of-plane relative the sketch in FIG. 3 ). By defining a network of connecting trenches in the wafer, a complex three-dimensional network of micro-glass channels can be obtained. Yet another embodiment of the process is to use a mold to shape non-spherical structures 18 ′. For example, a wafer with predefined etched cavities (e.g. cubical molds) can be temporarily attached on top of the glass before the step in FIG. 1 e . After the blowing in step in FIG. 1 e , hollow cubical glass structures 18 ′ would now be obtained instead of hollow semispheres (not shown). Many other types of glass shapes can be made by employing this molding principle similar to conventional blow molding at macroscopic scales. Using the processes in the above embodiments, multiple glass structures 18 can be batch fabricated simultaneously. The fabrication process also allows for potential integration of other electrical and mechanical components on the wafer 10 using conventional microfabrication techniques. If the wafer 10 needs to be diced, some care needs to be taken to assure that the glass 18 is not damaged. Several methods can be employed for this purpose, e.g. covering the wafer 10 with wax before the dicing. The wax can then be removed by heating the sample in a water bath. Alternatively the dicing can be performed before the glass is blown (between the steps in FIGS. 1 d and 1 e ). As was illustrated in the fabrication processes disclosed above, no external blowing needs to be involved in the fabrication of the glass spheres 18 although it may be included. Instead, the glass components 18 can be formed by themselves due to the increased pressure inside the sealed cavities 14 , which is understood to include the volume within the glass component 18 , when heated. An estimate of the pressure that develops inside the cavity can be obtained from the ideal gas law PV=nRT  (1) where P is the pressure, V is the volume, n is the number of moles, R is the Boltzmann constant, and T is the temperature. Since n and R are both constants, the ideal gas law can also be written as P 1 V 1 /T 1 =P 2 V 2 /T 2 . An estimate of the pressure that develops inside the cavity 14 before the glass 16 is deformed can be obtained from the ideal gas law (for constant volume): P=P i T f /T i where T f is the final temperature, T i is the initial temperature, and P i is the initial pressure. For example, inside a container that is initially at room temperature and atmospheric pressure, and is then heated to 1200 K, the pressure will increase to four atmospheres. In order to control the size of the glass shapes, the pressure inside the sealed chambers 14 needs to be controlled. Large shapes may be obtained by either increasing the pressure or increasing the volume of the etched cavity 14 . While it is also possible to increase the temperature at which the glass shapes are formed, the range of usable temperatures is pretty narrow since the temperature needs to be just slightly above the softening point of glass. Thus, the pressure and volume of the etched cavity will affect the size of the shapes to a greater extent than the temperature. If a larger cavity 14 is etched, a larger glass bubble 18 can be blown due to the ideal gas law at an elevated but constant temperature when the glass volume begins to expand: V=V etched P i /P f where V is the total volume enclosed by both the etched cavity and the deformed glass, V etched is the volume of the etched cavity only, P i is the initial pressure at an elevated temperature (just before the glass starts to deform), and P f is the final pressure once the bubble has been blown (˜1 atm if the self-inflation of the glass is performed in a furnace at atmospheric pressure). Making wafers 10 thicker and etching deeper cavities 14 is one way of achieving larger glass spheres. Alternatively the wafer 10 may be heated inside a vacuum furnace in order to amplify the pressure difference between the inside and outside of the etched cavity 14 by decreasing P f . Another option is to perform the anodic bonding inside a pressurized chamber, allowing precise control over P i . Yet another option is to fill the cavity 14 with a substance that vaporizes and increases the pressure inside the cavity 14 (i.e. increase P i ). Yet another mode to increase the volume of the etched cavity 14 is to use a 2-step DRIE process as illustrated in FIGS. 2 a - 2 d . After the initial DRIE etch in FIG. 2 a , the sidewalls are passivated and coated with a masking material. In FIG. 2 b the bottom of the cavities are then etched using either a dry or wet etchant. This will increase the etched volume for a certain depth, and thus enable the blowing of larger structures. Yet another alternative allowing for increased volume of the blown glass is shown in FIG. 7 . Here two silicon wafers have been bonded (before the glass was bonded). The first wafer now defines the “base” of the sphere, and the second wafer defines the volume (V etched ). The principles of the glass blowing processes described above are based on the free inflation and large deformation of an initially flat glass sheet at elevated temperatures. Thus, the modeling is related to that of biaxial inflation of viscoelastic membranes, commonly used for material characterization in the polymer industry. A few assumptions are made regarding the glass in order to model the fabrication process. At room temperature glass essentially behaves like an elastic solid, responding rapidly to applied stress. However at sufficiently high temperatures, stress is immediately relieved from the material due to the low viscosity of the glass. At high temperatures (and consequently low viscosities) glass can be modeled as a Newtonian fluid. Glass also has a viscoelastic region for viscosities between approximately 10 8 Pa-s and 10 13 Pa-s. In the fabrication processes described in the illustrated embodiments, the glass is shaped at temperatures between 850 and 900° C. The viscosity in this temperature region is less than 10 6 Pa-s for borosilicate glass. It is therefore assumed in the following that the glass can be modeled as an incompressible Newtonian fluid due to the low viscosity at the elevated temperatures. In the illustrated embodiments the glass blowing takes place inside a furnace at atmospheric pressure, although this need not be required in all embodiments. When the wafers 10 are placed inside the furnace, the high temperature will cause the pressure to increase rapidly inside the sealed cavities 14 of the silicon wafer 10 . At the same time the viscosity of the glass 16 decreases and the glass sheet 16 starts to deform. The glass 16 will grow into a spherical shape due to the uniform pressure distribution. After a sufficiently long period of time the pressure inside the glass shells, hemispheres or spheres 18 will be almost equal to the atmospheric pressure inside the furnace and most of the stresses in the glass shells 18 will be relieved. Since the final pressure is approximately equal on the inside and the outside of the hollow semisphere 18 and the cavities 14 were sealed at atmospheric pressure, the ideal gas law yields the following relation between the initial volume V e of the etched cavity 14 , and the volume of the blown glass shell 18 , V g = V e ⁡ ( T f T s - 1 ) ( 2 ) where T f is the furnace temperature and T s is the temperature at which the cavities 14 etched in the silicon wafer 10 were sealed by the glass wafer 10 . Note that this equation only holds true in the illustrated embodiment when the etched cavities are sealed at the same pressure as the pressure inside the furnace in which the shaping of the glass is performed (here 1 atm). As was previously discussed, the bonding and/or furnace pressures may alternatively be individually controlled in order to provide better control over the size and volume of the glass structures. In this case the complete ideal gas law has to be considered: P s V e /T s =P f (V e +V g )/T f , where P s and P f are the pressure at which the etched cavities are sealed and the pressure at which the glass structures are shaped (e.g. inside a furnace), respectively. From geometry considerations, the radius of curvature of the hollow glass semisphere 18 develops according to r g = h g 2 + r 0 2 2 ⁢ ⁢ h g ( 3 ) where h g is the height of the glass semisphere 18 and it is assumed that the undeformed membrane was circular with a radius of r 0 . Note that the height of the glass 16 is measured from the bottom of the undeformed glass sheet 16 to the interior wall of the top of the blown glass shell 18 , as illustrated in FIG. 3 . By considering the ratio between the volume of the undeformed glass membrane, πr 0 2 δ 0 , and the approximate final volume of the glass shell 18 , 2πr g h g δ, and assuming that the glass 16 is incompressible, the thickness of the hollow semisphere 18 can be estimated as δ = r 0 2 ⁢ δ 0 r 0 2 + h g 2 ( 4 ) where δ 0 is the initial thickness before the deformation. However, in reality the thickness will vary slightly over the surface of the shell 18 with the smallest thickness at the top. In the process that was illustrated in FIGS. 1 a - 1 e the etched cavity 14 is cylindrical and the blown glass shell 18 is spherical. Thus, their respective enclosed volumes are V e = π ⁢ ⁢ r 0 2 ⁢ h e ⁢ ⁢ and ( 5 ) V g = π 3 ⁢ h g 2 ⁡ ( 3 ⁢ ⁢ r g - h g ) . ( 6 ) By combining Equations (3) and (6), the final height of the semisphere 18 can be shown to develop as a function of the furnace temperature, the temperature at which the cavity 14 was sealed, and the depth and radius of the etched cavity 14 according to a. h g = [ ( 3 ⁢ ⁢ V g + r 0 6 ⁢ π 2 + 9 ⁢ ⁢ V g 2 ) ⁢ π 2 ] 2 3 - r 0 2 ⁢ π 2 π ⁡ [ ( 3 ⁢ ⁢ V g + r 0 6 ⁢ π 2 + 9 ⁢ ⁢ V g 2 ) ⁢ π 2 ] 1 3 ( 7 ) where V g =h e πr 0 2 (T f /T s −1) is obtained from Equations (2) and (5). While it is possible to shape glass over a wide range of temperatures, empirical trials show that if the temperature is lower than 800° C. it will take a long time for the glass spheres 18 to develop. Also, if the temperature is higher than 950° C. the spheres 18 tend to break due to the low viscosity at higher temperatures. The best shapes were obtained at temperatures between 850 and 900° C. when using Pyrex 7740 borosilicate glass. The height of the semisphere 18 as a function of the initial radius of the undeformed glass membrane (equal to the radius of the etched cavity) is plotted in FIG. 5 for etch depths of 300, 500, 700, and 900 μm. Plots are shown for both 850° C. (solid) and 900° C. (dashed). Note that the variation in height due to furnace temperature is relatively small in the region of 850-900° C. The radius of the etched cavity 14 has the largest influence on the final volume of the glass shell 18 due to the square of r 0 in Equation (5). In certain applications a highly spherical shape is desired. For example in a nuclear magnetic resonance gyroscope, which is the application that the wafer-level glass blowing was initially developed for, a spherical gas confinement chamber reduces the self-magnetization of the confined atoms due to symmetry. Thus, a spherical chamber can potentially improve the performance of the inertial instrument. In order to make the shells as spherical as possible, the base radius at the bottom of the hollow semisphere 18 should be small. Therefore it is advantageous to use thick wafers and etch deep cavities (large h e ) instead of increasing the etched radius. The ratio between the height and the diameter of the blown semispheres 18 , i.e., the sphericity measured in percent, is shown in the graph of FIG. 6 for different etch depths and as a function of the radius of the undeformed glass membrane. Naturally a narrower opening, r 0 , gives a more spherical shape. But even for a fairly large radius of 200 μm the estimated ratio between the height and the diameter of the semisphere 18 is greater than 90%, as long as the etched cavity 14 is deeper than 500 μm, as can be seen in FIG. 6 . An alternative process, which potentially allows for larger sphericity, is illustrated in FIG. 7 . In this process two silicon wafers 10 a and 10 b are bonded. The first double-side polished (thin) wafer 10 a will define the base of the hollow glass semisphere 18 and is etched all the way though with a small radius microhole 14 . In the second wafer 10 b a large chamber or enlarged microhole 14 ′ is etched. Once etched, the silicon wafers 10 a and 10 b are bonded using, for example, a fusion bond process. Next, a thin glass wafer is anodically bonded to wafer 10 a and the bonded wafers are then placed inside a furnace in order to blow the glass. In this process the radius of the base of the glass shell 18 , r 0 , can be designed to be much smaller than the radius of the cavity etched in wafer 10 b , r e . While it is here assumed that the cavity etched in wafer 10 b is cylinder-shaped, only the volume matters and wafer 10 b can readily be etched into any desired shape using either wet or dry etching. The final volume enclosed by the glass shell 18 is determined primarily by the volume of the cavity etched in wafer 10 b and the sphericity is now independent of the microhole's 14 ′ radius, r e . By utilizing this process, r 0 can be made as small as a few microns, which in turn gives a ratio between the height and the diameter of the blown hollow semisphere 18 of close to 100%, and thus potentially an almost perfect sphere. Consider the axis symmetric inflation of a thin circular membrane. Force equilibrium conditions lead to the following estimation of the pressure difference between the inside and outside of the resulting thin spherical membrane: Δ ⁢ ⁢ P = 2 ⁢ ⁢ δ r g ⁢ σ ( 8 ) where δ is the thickness of the membrane, r g is the radius of the semisphere, and σ is the stress. A few assumptions were made during the derivations of this equation. First, the shell thickness is assumed to be much thinner than the radius of curvature, so stress gradients across the shell 18 can be ignored. Furthermore, the thickness of the inflated membrane is assumed to be uniform. While this is not quite true for the described glass blowing process, the above spherical shell equation can still be used to get an idea of the approximate blow-up time of the glass spheres 18 . As was previously discussed, the properties of the heated glass 16 depend on the temperature. For low temperatures the glass 16 behaves like an elastic solid, but for higher temperatures viscoelastic models are normally used. At very high temperatures glass is modeled as a Newtonian fluid. The stress can be split into a viscoelastic part and a viscous part. The resistance to fast deformations is determined primarily by the viscous response. Now consider the top of the hollow semisphere 18 , where the flow is purely elongational due to the biaxial stretching of the membrane. For elongational flows of a Newtonian fluid the stress is given by σ=−3ηdε/dt, where η is the viscosity and dε/dt is the strain rate. The strain is ε=ln(δ/δ 0 ), and hence the stress can be written as σ = - 3 ⁢ ⁢ η ⁢ ⅆ ⅆ t ⁢ ( ln ⁢ δ δ 0 ) . ( 9 ) In order to estimate the time required to shape the glass 16 , Equations (8) and (9) are combined. The height of the glass shell, h g , now develops according to Δ ⁢ ⁢ P = 24 ⁢ ⁢ η ⁢ ⁢ r 0 2 ⁢ δ 0 ⁢ h g 2 ( r 0 2 + h g 2 ) 3 ⁢ ⅆ h g ⅆ t ( 10 ) where ΔP=P i −P o is the pressure difference between the inside, P i , and outside, P o , of the shell 18 . In the fabrication process illustrated in FIGS. 1 a - 1 e , P o is equal to the furnace pressure (1 atm). The pressure inside the glass shell 18 depends on the furnace temperature as well as the time-dependent height of the semisphere 18 . The magnitude of this pressure was derived from the ideal gas law and the geometry considerations above as P i = P s ⁢ T f T s 1 + h g 6 ⁢ ⁢ r 0 2 ⁢ h e ⁢ ( h g 2 + 3 ⁢ ⁢ r 0 2 ) ( 11 ) where P s is the pressure at which the cavities 14 etched in the silicon wafer 10 were sealed by the glass wafer (assumed to be 1 atm). It was also assumed that the glass membrane will not significantly deform until the final temperature has been distributed uniformly throughout the wafer, and thus the ideal gas law can be applied. This assumption was based on the fact that the wafers are small and quickly positioned inside the furnace and should therefore heat fairly uniformly as well as rapidly. While this assumption does not quite hold true in reality, it is sufficient for the rough estimations of the order of magnitude of the blow-up time presented here. As described by equations (10) and (11), the pressure difference, ΔP, increases rapidly to a few atmospheres when the wafers are placed inside the furnace. As the glass shell 18 grows, the pressure inside the shell 18 will decrease until it is almost equal to the pressure inside the furnace (1 atm). After a sufficient period of time, the pressure difference will be close to zero. The plot in FIG. 8 was obtained from equations (10) and (11). The height of the hollow glass semisphere 18 is shown for etch depths of 300, 500, 700, and 900 μm. It was assumed that the etched radius, r 0 , was 200 μm, the initial glass thickness, δ 0 , was 100 μm, and the viscosity of glass, η, was 10 6 Pa-s (approximate viscosity of borosilicate glass at 850° C.). The blow-up time is on the order of 15 s. Since a few extra seconds need to be added to allow for the heating of the wafers, the time required to fully form the glass spheres 18 inside a furnace is estimated to be on the order of one minute. In the discussion above it was assumed that the thickness of the glass 16 was uniform throughout the surface of the shell 18 . However, due to the viscous nature of the heated glass 16 this is not true. The top of the semisphere 18 will be slightly thinner than the parts closer to the base. An estimate of the nonuniform wall thickness of the shell can be derived δ = δ 0 ⁡ [ r 0 4 + r 2 ⁢ h g 2 r 0 2 ⁡ ( r 0 2 + h g 2 ) ] 2 ( 12 ) where a particle that was initially positioned at radius r before the circular membrane was deformed is considered. As the glass 16 is blown and forms a hollow semisphere 18 , this particle travels to a new position as shown in FIG. 9 . Note that in the middle of the membrane, and thus the thickness of the top of the glass shell 18 is described by. δ=δ 0 (1+h g 2 /r 0 2 ) −2 . Depending on the particular application of the glass structures, a nonuniform wall thickness may be more or less detrimental. For some applications this property can even be utilized, e.g., to create microlenses. The focal length of a glass shell due to the nonuniform wall thickness can be estimated from the lens makers' equation 1 f = ( n g - n 0 ) ⁢ ( 1 R 1 - 1 R 2 ) ( 13 ) where R 1 and R 2 are the two different meridional radii of curvature, and n g and n 0 are the refractive indices of the glass and the surrounding medium, respectively. Consider again an example of an actual fabrication according to the process illustrated in FIGS. 1 a - 1 e . The fabrication was performed using 2-inch diameter single crystal silicon and Pyrex 7740 wafers 10 . An array of cylindrical cavities 14 was first etched in the silicon wafer using deep reactive ion etching (DRIE). Structures have been successfully fabricated for etched diameters ranging from 100 to 1000 μm. The targeted depth of the etched cavities 14 varied from 300 to 800 μm. Once the cavities were etched in the silicon wafer 10 , a 100 μm thin Pyrex 7740 sheet 16 was anodically bonded to the silicon wafer 10 . The bonding was done at atmospheric pressure on top of a hot plate set to 400° C. and using a voltage of 600 V. Next the wafers 10 were diced using a diamond saw. Optionally the wafer 10 can be diced after the blowing of the glass shells 18 but in order to avoid potential damages to the glass structures the dicing was here performed before the hollow glass semispheres 18 are blown. If the dicing is instead performed as the last fabrication step, some additional care needs to be taken in order to protect the fragile glass shells. The wafers 10 were placed inside a furnace at a temperature of approximately 850° C. for about 3 minutes in order to shape the glass spheres. As was previously discussed, an issue that potentially affects the final shape of the shells 18 in the illustrated embodiments the temperature used during the anodic bonding. The final height (and consequently radius) of the glass shells 18 depends on the temperature at which the etched chambers were sealed, T s . Above it has been assumed that is equal to room temperature. However, in order for this assumption to be valid, a sufficient force must be applied to the top electrode until the anodic bonding is completed to provide a temporary seal between the glass 16 and the silicon of wafer 10 . If the glass 16 and silicon wafers 10 are not perfectly sealed in this manner at room temperature, some air will escape from the etched cavities 14 when heated during the anodic bonding, leading to a higher and thus a smaller final height of the glass shells 18 . The anodic bonding can alternatively be performed inside a pressure chamber. By controlling both the temperature and the pressure during the anodic bonding, the final size of the glass shells 18 can be accurately predicted. Once the hollow glass spheres 18 are fabricated, a few optional fabrication steps may be required depending on the particular application. For example, if the chambers need to be filled with gas or other substances, it may be necessary to open the backside 20 of the wafer 10 . The backside 20 can be patterned and etched using either wet or dry etchants to gain access to the hollow semispheres 18 (assuming the glass shells on the front side are protected). If double-side polished wafers are used, a rim can be maintained on the backside that will allow for resealing of the chamber using anodic bonding techniques. Other additional processing steps may include applying an anti-relaxation coating, etching of the bulk glass to gain access to the silicon, and integration with other electrical and mechanical components. The fabricated shells in the example above were covered with photoresist and diced at the center of the spheres 18 in order to be able to perform metrology. A scanning electron microscope image of the cross-section of one of the hollow semispheres is shown in FIG. 10 . The shell 18 was fabricated using a 1 mm thick silicon wafer bonded to a 100 μm thin Pyrex 7740 wafer 10 , and was formed at 850° C. The cylinder-shaped etched cavity 14 is 750 μm deep and 500 μm in diameter. Table I shows a comparison between the experimental results and the values predicted by the presented analytical model, calculated using the equations above as specified in the table. TABLE I COMPARISON BETWEEN THE GlASS BLOWING MODEL AND THE EXPERIMENTAL RESULTS Chip 1 (h e = 350 μm, r 0 = 375 μm) Chip 2 (h e = 750 μm, r 0 = 250 μm) Parameter Equation Calculated Sphere 1 Sphere 2 Sphere 3 Calculated Sphere 4 Sphere 5 Sphere 6 Glass height, h g (7) 794 μm 806 μm 834 μm 718 μm 860 μm 818 μm 814 μm 803 μm Glass radius, r g (3) 486 μm 520 μm 540 μm 479 μm 466 μm 431 μm 439 μm 436 μm Uniform thickness, δ (4)  18 μm N/A N/A N/A  7.8 μm N/A N/A N/A Thickness at top, δ (12)    3.3 μm  14 μm  13 μm  14 μm   0.6 μm   5.3 μm   5.5 μm   7.2 μm Thickness at side, δ (12)   33 μm  28 μm  22 μm  29 μm  18 μm  11 μm  12 μm  16 μm Two different chips from wafer 10 were diced and three glass shells 18 were measured on each chip. Chip 1 was fabricated from a 450 μm thick silicon wafer by etching 350 μm deep cavities with a radius of 375 μm. A 1-mm-thick wafer was instead used to fabricate Chip 2 , with an etch depth of 750 μm and a radius of 250 μm. The calculated height and radius agree with the experimental values in Table I. However, both equations (4) and (12) failed to predict the final thickness of the shells 18 . While the thickness was not quite uniform, the thickness variation was overestimated using equation (12). Instead the true glass thickness was somewhere in between the thicknesses predicted by the uniform and the nonuniform models. It should be mentioned that two other variables may have affected the results in Table I. First, while great care was taken to attempt to dice the cross-sections in the middle of the spheres 18 , a slight offset from the center was inevitable. Therefore the actual height and radius of the glass spheres 18 may be slightly larger than the values displayed in Table I. In addition, the specified thickness of the Pyrex 7740 wafer was 100 μm±25 μm. This potential variation of 50 μm naturally leads to some discrepancies in the thickness results. The surface quality of both the inside and the outside of the side of the glass semisphere 18 (dashed area in FIG. 10 ) was measured using an optical profiler (Hyphenated-Systems NanoScale 150OP). Although both surfaces were still relatively smooth, the surface roughness was greater on the outside surface. The specified initial surface roughness of the Pyrex 7740 wafers was <10 Å. The average surface roughness after the spheres were formed was 2 nm on the inside surface and 9 nm on the outside. It is believed that the reason for this difference in surface roughness is that the inside surface was subjected to a uniform pressure during the blowing of the spheres, while the outside surface was directly exposed to the surrounding nitrogen gas flow and particulates inside the furnace. Many alterations and modifications may be made by those having ordinary skill in the art without departing from the spirit and scope of the invention. Therefore, it must be understood that the illustrated embodiment has been set forth only for the purposes of example and that it should not be taken as limiting the invention as defined by the following invention and its various embodiments. Therefore, it must be understood that the illustrated embodiment has been set forth only for the purposes of example and that it should not be taken as limiting the invention as defined by the following claims. For example, notwithstanding the fact that the elements of a claim are set forth below in a certain combination, it must be expressly understood that the invention includes other combinations of fewer, more or different elements, which are disclosed in above even when not initially claimed in such combinations. A teaching that two elements are combined in a claimed combination is further to be understood as also allowing for a claimed combination in which the two elements are not combined with each other, but may be used alone or combined in other combinations. The excision of any disclosed element of the invention is explicitly contemplated as within the scope of the invention. The words used in this specification to describe the invention and its various embodiments are to be understood not only in the sense of their commonly defined meanings, but to include by special definition in this specification structure, material or acts beyond the scope of the commonly defined meanings. Thus if an element can be understood in the context of this specification as including more than one meaning, then its use in a claim must be understood as being generic to all possible meanings supported by the specification and by the word itself. The definitions of the words or elements of the following claims are, therefore, defined in this specification to include not only the combination of elements which are literally set forth, but all equivalent structure, material or acts for performing substantially the same function in substantially the same way to obtain substantially the same result. In this sense it is therefore contemplated that an equivalent substitution of two or more elements may be made for any one of the elements in the claims below or that a single element may be substituted for two or more elements in a claim. Although elements may be described above as acting in certain combinations and even initially claimed as such, it is to be expressly understood that one or more elements from a claimed combination can in some cases be excised from the combination and that the claimed combination may be directed to a subcombination or variation of a subcombination. Insubstantial changes from the claimed subject matter as viewed by a person with ordinary skill in the art, now known or later devised, are expressly contemplated as being equivalently within the scope of the claims. Therefore, obvious substitutions now or later known to one with ordinary skill in the art are defined to be within the scope of the defined elements. The claims are thus to be understood to include what is specifically illustrated and described above, what is conceptionally equivalent, what can be obviously substituted and also what essentially incorporates the essential idea of the invention.
A method for glass-blowing on a microscopic level includes the steps of defining a plurality of microholes in a wafer, disposing a sheet of thermally formable material onto the wafer covering the microholes, heating the sheet of thermally formable material until a predetermined degree of plasticity is achieved, applying self-induced fluidic pressure by expansion of the heated trapped gas in the microholes to the sheet of thermally formable material, while the sheet is still plastic, and simultaneously forming a plurality of blown micro-objects in the sheet on the wafer by means of continued application of pressure for a predetermined time.
8
BACKGROUND OF THE INVENTION This invention relates generally to devices and techniques which facilitate the hanging of picture frames and the like. More particularly, this invention relates to devices which aid in the proper positioning of the picture frame. One of the most common household tasks is to hang a picture frame in the proper location and the proper orientation. Typically, a screw, nail or hook with a fastener is mounted to the wall. The back of the frame includes a picture frame wire or other hanger of various functions and forms which is then engaged with the mounted hardware fastener. The precise positioning of the nail, screw or hook is always highly problematic since it is extremely difficult to precisely locate same. Conventionally, the mounting hardware is obstructed by the picture frame when a trial position is attempted and the ultimate hanging relationship is not easily replicated. For large pictures where two suspension points are desired, it becomes quite problematic to properly align the two points for positioning the mounting support. It is well known that one common technique is to essentially guess at the proper position and mark the position more or less with a pencil with the position being essentially blindly marked so that the location of the fastener can be approximated. The problems are also compounded by the difficulties in assessing the proper tensioning on flexible picture frame wires when the weight of a picture frame and the engagement with the wall is finalized. The present invention is a locator used for hanging a picture frame which makes the foregoing positioning process much more precise, predictable and easy. SUMMARY OF THE INVENTION Briefly stated, the invention in a preferred form is a locator device for locating the proper anchor position for hanging a frame. The locator device in one embodiment is adaptable for use with a single anchor mount application and in another embodiment is adaptable for both single and dual frame anchor mounts. The locator device comprises an elongated arm having longitudinally spaced first and second positions. A handle which may be a rod-like member projects orthogonally from the first position. A suspension/marker assembly is disposed at the second position. The suspension/marker assembly comprises a marker and a head for receiving a frame hanger. The assembly comprises a plunger having opposed first and second ends with the head being mounted at the first end and the second end having a pointed configuration. The head has a groove for receiving the frame hanger. The arm further has a bore which receives a portion of the plunger with the plunger point configuration being retracted within the bore in a normal mode and being projectable to extend beyond the bore to mark the proper anchor mount location. A pad may also be mounted to the surface arm at a position generally opposite the head. The locator device in a second embodiment comprises a first arm having a first boss for suspending a frame hanger and a first marker positioned in close proximity to the first boss. The second arm has a second boss for suspending the frame hanger and la second marker positioned in close proximity to the second boss. A connector connects the arms at a selected fixed angular relationship. The connector may comprise a threaded fastener extending through end locations of the arms and preferably has a wing nut threadable with a fastener. A handle is connected by the connector to the arms and is also positionable in a fixed angular relationship with respect to the arms. The handle further comprises a plate-like member which defines an opening to facilitate holding by the fingers. The handle may also have a second opening, and the handle is positioned between the first and second arms wherein a fastener extends through the arms and the connector. The marker preferably takes the form of a plunger having a point which is projectable beyond the boss. In one form of the invention, the point is formed from lead. A pad is mounted on an end of the plunger opposite the point. The boss also preferably comprises a central bore which receives the plunger assembly. In a normal mode, the pointer is retracted within the boss. In an activated mode, the plunger extends beyond the boss. The bosses and markers are preferably substantially identical. The first and second arms form a vertex with the connector being disposed at the vertex, and the markers are disposed generally opposite the vertex to facilitate precisely locating two anchor points for the hanger frame. In this regard, the boss preferably defines a generally arcuate groove for receiving the frame hanger. It should be appreciated that either one or both arms may be employed depending on whether it is desired to locate a single anchor point or dual anchor points. The locator device is configured so that the frame may be suspended from the locator device, and when the proper position is determined, the frame is slightly depressed against the plunger assembly to force the markers to project from the boss to mark the proper locations on the wall or mounting surface. An object of the invention is to provide a new and improved locator for use in hanging a picture frame which eliminates many of the drawbacks and problems with conventional hanging techniques. An object of the invention is to provide a new and improved tool for facilitating the hanging of a picture. A further object of the invention is to provide a new and improved tool which precisely locates the proper position of the picture hanger in an efficient and highly reliable manner. Another object of the invention is to provide a new and improved hanger for a picture frame which eliminates guesswork in properly locating the position for a picture frame fastener. A further object of one embodiment of the invention is to provide a new and improved tool for hanging picture frames which is readily adjustable to provide the proper position for either a single or a multiple mounting support. Other objects and advantages of the invention will become apparent from the drawings and the detailed description. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a picture frame hanger locator illustrating the locator in a position for locating a pair of mounts; FIG. 2 is a rear view of the picture hanger locator of FIG. 1 , illustrating the locator for locating a single mount, portions being broken away and portions shown in phantom; FIG. 3 is a side sectional view of the picture hanger locator of FIG. 1 taken along the line 3 — 3 thereof; FIG. 4 is a side sectional view of the picture hanger locator of FIG. 1 taken along the line 4 — 4 thereof; and FIG. 5 is a front view, partly in schematic and partly shown in broken lines, illustrating the use of the locator of FIG. 1 for hanging a picture; FIG. 6 is a front view, partly in schematic and partly in broken lines, illustrating a second mode for hanging a picture using the locator of FIG. 6 ; FIG. 7 is a side sectional view, illustrating the relationship between the wall and locator and a picture frame for the locator of FIG. 1 , which is partially illustrated; FIG. 8 is a diagram illustrating a method for mounting a picture frame using the locator of FIG. 1 ; FIG. 9 is a side view, partly broken away and partly in section of another embodiment of a picture frame hanger locator in accordance with the present invention; and FIG. 10 is a side sectional view, illustrating a relationship between the wall and the locator and a picture frame for the locator of FIG. 9 , which is partially illustrated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to the drawings wherein like numerals represent like parts throughout the figures, a locator for use in hanging picture frames and similar items is designated generally by the numeral 10 . The locator 10 facilitates the hanging of picture frames 12 , 14 by properly locating the proper position for the nail, screw, hook or other anchoring fastener (not illustrated) which is to be fixed to the wall W or support structure for suspending the frame. As illustrated in FIGS. 5 , 6 and 7 , the locator 10 functions to replicate the suspended configuration of the picture frame/hanger and to precisely locate the picture in a precise position for either a single ( FIG. 6 ) or dual anchoring ( FIG. 7 ) mount. It will be appreciated that for the dual anchor mount, the locator also aides in the proper horizontal alignment of the mounting hardware. The locator 10 comprises a pair of pivotally connected elongated arms 20 and 30 . The arms are joined by a wing nut 42 which threads against a bolt 40 . A hanger 50 is disposed between the ends of the arms 20 and 30 and is also pivotally joined therewith. The hanger 50 preferably includes an opening 52 or other contoured surface to allow sufficient grasping with a finger to allow a suspension therebelow. It will be appreciated that the arms 20 , 30 and the handle 50 are adjustable to form a fixed relationship at any of a wide range of angles. The wing nut 42 is then tightened to provide the desired configuration. For a dual mount location configuration as illustrated in FIGS. 1 and 5 , the arms 20 , 30 form an inverted V-shaped configuration. For a single mount configuration, the arm 30 may be pivoted away or in a linear configuration such as illustrated in FIGS. 2 and 6 . Each arm carries a selectively projectable marker assembly 60 which is best illustrated in FIG. 4 . The rear side of each arm includes a boss 62 with a circumferential groove 64 , which is contoured to receive the wire hanger 13 , 15 of the associated picture frame 12 , 14 . The boss 62 forms an interior cavity 66 which, in a normal mode, receives a pointed tip 68 of a plunger 70 . The plunger 70 includes a head 72 with a pad 74 at the frontal side of the arm. A spring 76 is disposed between the underside of the head and the arm to urge the pointer to the retracted position illustrated in FIG. 4. A pin 78 may be threaded through the end of the plunger to retain same to the arm. The tip 68 of the plunger may be in the form of a lead point, or may merely be a sharp point which will place a mark or depression in the support surface W when it is depressably projected through the cavity 66 . The tip 68 may alternatively be covered with a marking substance to facilitate marking for example, the tip 68 may be depressed and brought into contact or rubbed with a crayon or graphite may be applied. As best illustrated in FIGS. 5-7 and described in the diagram of FIG. 8 , a picture frame 12 or 14 is suspended from the locator by means of the picture frame wire 13 or 15 being positioned in the groove 64 on the top of the boss 62 with the head pad 74 being disposed against the back of the frame and the boss 62 being disposed against the wall W or the support surface. The installer then grasps the hanger 50 and moves the locator with the suspended picture frame to the proper position. When the proper positioning is obtained, a light force is transmitted against the frame in the direction of the FIG. 7 arrow to project the point 68 to mark the proper position on the wall. It will be appreciated that the hanger 10 may be suitably adjusted (by angular positioning of arms 20 and 30 ) and the frame suspended for either a single ( FIG. 5 ) or a double point ( FIG. 6 ) location. After the position has been properly marked, the picture frame is then dismounted from the locator and the fastener is positioned at the properly marked point, for example, a screw, nail or other hook type fastener may then be mounted to the wall. The picture frame may be then suspended from the fastener and will accurately replicate the position previously marked on the wall. It will be appreciated that the suspension configuration of the picture will be replicated and that the precise location for the anchoring point will be determined by the locator 10 . With reference to FIGS. 9 and 10 , a second embodiment of a locator for use in hanging a picture frame is generally designated by the numeral 100 . The locator 100 facilitates a hanging of a picture frame by property locating the proper position for the anchoring fastener which is to be fixed to the wall W or support structure for suspending the frame when only a single anchor point is required. The locator 100 comprises an elongated arm 120 . A rod-like handle 150 projects forwardly from an upper portion of the arm. A suspension/marker assembly 160 is positioned at a generally opposite location of the arm 120 and carried by the arm. The assembly 160 includes a head 162 with a circumferential groove 164 , which is contoured to receive a flexible wire hanger 113 of an associated picture frame 114 . The head 162 is mounted to a plunger 170 which is partially received in a throughbore 106 of the arm. The spring 176 of the plunger is disposed between the head 162 and the front surface 102 of the arm. The distal end 172 of the plunger is pointed and in a normal mode is retracted within the throughbore 106 . Preferably, a soft pad 180 is mounted on the rear surface 104 of the arm and also includes an opening communicating with the throughbore 106 . The pad 180 may have a fabric or rubber composition. The plunger 170 includes a slot 178 and a pin 182 extends through an edge of the arm to retain the plunger assembly to the arm. The point may be contacted against a crayon or other similar marking substance to facilitate marking the wall. As best illustrated in FIG. 10 and described in FIG. 8 , the frame 114 is suspended by reception of hanger 113 in the groove 164 and the locator 100 is held via the handle 150 . The locator with the suspended picture frame is then moved to the proper position. When the proper positioning is obtained, a light force is applied against the front of the picture frame in the direction of the FIG. 10 arrow to project the point 172 to mark the proper position on the wall W. After the position has been properly marked (not illustrated), the picture frame is then dismounted from the locator 100 and the fastener is positioned at the properly marked point P where, for example, a screw, nail or other hook type fastener may then be mounted to the wall. The picture frame is then suspended from the fastener to accurately replicate the optimum previously marked position. While a preferred embodiment of the invention has been set forth for the purposes of illustration, the foregoing description should not be deemed a limitation of the invention herein. Accordingly, various adaptations, modifications and alternatives may occur to one skilled in the art without departing from the spirit and the scope of the invention.
A locator for hanging picture frames employs an arm which has a handle dispose at one end. A suspension/marker assembly is carried at a second position of the arm. The suspension/marker assembly comprises a plunger which has a point and also mounts a head which receives a frame hanger. Embodiments are disclosed for both a single mount and for a single or a dual mount application.
0
BACKGROUND OF THE INVENTION This invention relates to certain 4-amino- b 6,7-dimethoxy-2-(6,7-disubstituted-1,2,3,4-tetrahydroisoquinol-2-yl)quinolines which are useful in the treatment of cardiac arrhythmias in human subjects. SUMMARY OF THE INVENTION Thus the invention provides compounds of the formula: ##STR1## and their pharmaceutically acceptable salts, wherein one of R 1 and R 2 is methoxy and the other is a group of the formula --OH, --O.CO(C 1 -C 4 alkyl), --O.COPh or --O.COCH 2 Ph where Ph is a phenyl group optionally substituted by one or two substituents each independently selected from F, Cl, Br, I, CF 3 , C 1 -C 4 alkyl and C 1 -C 4 alkoxy. Preferably, ether R 1 is hydroxy and R 2 is methoxy or R 1 is methoxy and R 2 is hydroxy. DETAILED DESCRIPTION OF THE INVENTION The compounds of the formula (I) in which one of R 1 and R 2 is methoxy and the other is hydroxy can be prepared by the cyclisation of a compound of the formula: ##STR2## wherein one of R 3 and R 4 is methoxy and the other is either hydroxy or a protected hydroxy group, preferably benzyloxy. It is preferred to use a protected hydroxy group. The intermediates of the formula (II) also form a part of the invention. The cyclisation is preferably carried out with a Lewis acid, e.g. zinc chloride or bromide, or aluminium chloride. The use of zinc chloride is preferred. The reaction is typically carried out by heating the compound (II) with zinc chloride in a suitable organic solvent, e.g. dimethylacetamide, and preferably under reflux. The reaction mixture is then treated with a base such as aqueous 2.0-2.5N sodium hydroxide to destroy any complexes that the zinc chloride may form with the end product. The product can then be isolated and purified by conventional techniques. When one of R 3 and R 4 is a protected hydroxy group, then the protecting group will need to be removed after cyclisation to generate compounds of formula (I) where R 1 or R 2 is OH. Benzyl groups are typically removed by hydrogenating the benzyloxy compound in methanol at about 2.068×10 5 Pa (30 psi) at room temperature in the presence of a palladium-on-carbon catalyst. The compounds of the formula (I) in which one of R 1 and R 2 is --O.CO(C 1 -C 4 alkyl), --O.COPh or --O.COCH 2 Ph can be prepared by the acylation of the corresponding hydroxy-compounds according to conventional techniques, e.g. using an appropriate acid chloride or anhydride. Protection of the 4-amino group is not usually necessary. The intermediates of the formula (II) in which R 3 is methoxy and R 4 is benzyloxy can be prepared as follows: ##STR3## Similary, the intermediates of the formula (II) in which R 3 is benzyloxy and R 4 is methoxy can be prepared from the corresponding 6-hydroxy-7-methoxytetrahydroisoquinoline. The intermediates of the formula (II) in which one of R 3 and R 4 is methoxy and the other is hydroxy can be prepared similarly to the above but with the omission of the benzylation step and provided that the level of phosphorus oxychloride is increased in the final step. The 1,2,3,4-tetrahydroisoquinoline hydrochloride starting materials are described in J. Org. Chem., vol. 30, pages 2247-2250 (July 1965). Also according to the invention, there is provided a method of treatment of cardiac arrthythmias which comprises administering to a human subject suffering from or liable to cardiac arrhythmias an effective cardiac arrhythmia reducing or preventing amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof. The invention also provides a compound of the formula (I), or a pharmaceutically acceptable salt thereof, for use as a medicament. Also, the invention further provides the use of the compound of formula (I), or of a pharmaceutically acceptable salt thereof, for the manufacture of a medicament for the prevention or reduction of cardiac arrhythmias. The ability of the compounds of the formula (I) to reduce or prevent cardiac arrhythmias can be assessed by their antagonism of adrenaline-induced ventricular arrhythmias when administered intravenously to anaesthetised dogs. The ability of the compounds of the formula (I) to reduce or prevent cardiac arrhythmias can also be assessed by their ability to antagonise picrotoxin-induced ventricular arrhythmias in anaesthetised cats. It is expected that for human use in the prevention or reduction of cardiac arrhythmias single, oral dosages of a compound of formula (I) will be in the range from 0.1 to 10.0 mg per day for an average adult patient (70 kg), taken in up to 4 doses per day. Thus individual tablets or capsules might contain from 0.025 to 10.0 mg of active compound, in a suitable pharmaceutically acceptable vehicle or carrier. Single dosages for parenteral, e.g. intravenous, administration would be expected to be within the range from 0.1 to 10 micrograms/kg taken in up to 4 doses per day, e.g. 5 to 1000 micrograms, as required. A severe cardiac arrhythmia is preferably treated by the intravenous route in order to effect a rapid conversion to normal sinus rhythm. Variations on these dosages may occur depending on the weight and condition of the subject being treated, as will be determined by the medical practitioner. The compounds of the formula (I) and their pharmaceutically acceptable salts can be administered alone, but will generally be administered in admixture with a pharmaceutical carrier selected with regard to the intended route of administration and standard pharmaceutical practice. They can be administered both to patients suffering from arrhythmias and also prophylactically to those likely to develop arrhythmias. For example they may be administered orally in the form of tablets containing such excipients as starch or lactose, or in capsules either alone or in admixture with excipients, or in the form of elixirs or suspensions containing flavouring or colouring agents. They may be injected parenterally, for example, intravenously, intramuscularly or subcutanesously. For parenteral administration, they are best used in the form of a sterile aqueous solution which may contain other solutes, for example, enough salts or glucose to make the solution isotonic with blood. The pharmaceutically acceptable acid addition salts of the compound of the formula (I) are salts formed from acids which form non-toxic salts such as the hydrochloride, hydrobromide, hydroiodide, sulphate or bisulphate, phosphate or hydrogen phosphate, acetate, maleate, fumarate, lactate, tartrate, citrate, gluconate, benzoate, methanesulphonate, benzenesulphonate and p-toluenesulphonate salts. Since the compounds of the formula (I) are phenolic, they may also form metal salts, e.g. alkali metal salts such as sodium salts. The antiarrhythmic properties of the compounds of formula (I) may also be enhanced by use in combination with a non-selective beta-adrenoceptor blocking compound, such as propranolol, or with a cardio-selective beta-adrenoceptor blocking agent, such as atenolol. The following Examples, in which all temperatures are in °C., illustrate the invention. "Merck Art.9385" is the trade mark of a brand of silica. EXAMPLE 1 4-Amino-6,7-dimethoxy-2-(6-hydroxy-7-methoxy-1,2,3,4-tetrahydroisoquinol-2-yl)quinoline ##STR4## (A) 4-Amino-2-(6-benzyloxy-7-methoxy-1,2,3,4-tetrahydroisoquinol-2-yl)-6,7-dimethoxyquinoline N-(1-[6-benzyloxy-7-methoxy-1,2,3,4-tetrahydroisoquinol-2-yl]ethylidene)-2-cyano-4,5-dimethoxyaniline (10.92 g), anhydrous zinc chloride (3.16 g) and dimethylacetamide (25 ml) were mixed at 20° and then stirred at reflux for two hours. The reaction mixture was allowed to cool to about 40° and then 2N sodium hydroxide (16 ml) was added. The mixture was cooled to 25° and stirred for fifteen mixtures. 2N Sodium hydroxide (10 ml) and water (50 ml) were added and the reaction mixture was then extracted with methylene chloride (3×100 ml). The combined organic extracts were washed (H 2 O), dried (MgSO 4 ) and evaporated in vacuo. The residue was chromatographed on silica (Merck "Art.9385") under medium pressure eluting with methylene chloride containing gradually increasing amounts (1-20%) of methanol. The combined product-containing fractions were evaporated and the residue was recrystallised from ethanol and washed (Et 2 O) to give 4-amino-2-(6-benzyloxy-7-methoxy-1,2,3,4-tetrahydroisoquinol-2-yl)-6,7-dimethoxyquinoline (7.1 g) as a pale yellow powder, m.p. 181°-2°. Analysis %: Found: C, 70.81; H, 6.50; N, 8.68; Calculated for C 28 H 29 N 3 O 4 : C, 71.32; H, 6.20; N, 8.91. (B) 4-Amino-6,7-dimethoxy-2-(6-hydroxy-7-methoxy-1,2,3,4-tetrahydroisoquinol-2-yl)quinoline A suspension of the product of part (A) (3.0 g) in methanol (400 ml) was warmed at about 50° until the majority of the product dissolved. The reaction mixture was then transferred to a hydrogenator and hydrogenated under a hydrogen pressure of 2.068×10 5 Pa (30 psi) in the presence of 5% Pd/C (400 mg) at room temperature with stirring for 1.5 hours. The reaction mixture was filtered through "Arbacel" (a microcrystalline cellulose filtration aid), and evaporated to yield impure 4-amino-6,7-dimethoxy-2-(6-hydroxy-7-methoxy-1,2,3,4-tetrahydroisoquinol-2-yl)quinoline (600 mg). The catalyst was then stirred in methylene chloride/methanol (4:1, 200 ml) for 30 minutes, and the mixture was filtered and the filtrate evaporated to yield a further 1.05 g of the impure product. The total of the impure product (1.65 g) was dissolved in methylene chloride/methanol (4:1, 300 ml) and shaken with 10% sodium carbonate solution (50 ml). The organic phase was washed (H 2 O), dried and evaporated. Medium pressure chromatography of the residue on silica (Merck "Art.9385") eluting with methylene chloride containing gradually increasing amounts of ethanol (1-25%) followed by collection and evaporation of appropriate fractions gave the title compound. The compound was slurried in boiling methylene chloride (20 ml), cooled, precipitated with hexane, filtered, and the solid washed with hexane and dried to give the pure title compound as a quarter-hydrate (900 mg), m.p. 250°- 251°. Analysis %: Found: C, 65.62; H, 6.27; N, 10.47; Calculated for C 21 H 23 N 3 O 4 .1/4H 2 O: C, 65.35; H, 6.14; N, 10.89. EXAMPLE 2 4-Amino-6,7-dimethoxy-2-(7-hydroxy-6-methoxy-1,2,3,4-tetrahydroisoquinol-2-yl)quinoline (A) 4-Amino-2-(7-benzyloxy-6-methoxy-1,2,3,4-tetrahydroisoquinol-2-yl)-6,7-dimethoxyquinoline, m.p. 198°-9°, was prepared similarly to Example 1(A), using the product of Preparation 6, zinc chloride, dimethylacetamide, and 2.5N NaOH. Analysis %: Found: C, 70.24; H, 6.02; N, 8.79; Calculated for C 28 H 29 N 3 O 4 .1/2H 2 O: C, 69.98; H, 6.29; N, 8.74. (B) 4-Amino-6,7-dimethoxy-2-(7-hydroxy-6-methoxy-1,2,3,4-tetrahydroisoquinol-2-yl)quinoline hydrochloride, m.p. 204°-5°, was prepared similarly to Example 1(B) by the reduction of the corresponding 7-benzyloxy compound with H 2 /Pd/C in methanol. In this instance the product was isolated as a hydrochloride. This is believed to be due to the presence of chloride ions in the catalyst. Analysis %: Found: C. 60.18; H, 5.75; N, 9.55; calculated for C 21 H 23 N 3 O 4 .HCl: C, 60.35; H, 5.79; N, 10.06. The following Preparations, in which all temperatures are in °C., illustrate the preparation of certain starting materials: PREPARATION 1 N-Acetyl-6-hydroxy-7-methoxy-1,2,3,4-tetrahydroisoquinoline ##STR5## 6-Hydroxy-7-methoxy-1,2,3,4-tetrahydroisoquinoline hydrochloride (15.47 g) was converted to the free base by dissolving it in water (about 100 ml) and adding concentrated (0.88) aqueous ammonia to pH 9-10, giving a precipitate of the free base. The precipitate refused to extract completely into chloroform (100 ml.). The aqueous phase was therefore filtered and the solid washed (EtOH) and dried. The chloroform extract was dried (MgSO 4 ) and evaporated. The two solids were combined to give the free base as a pale powder (11.94 g). A suspension of the free base (11.94 g) in methylene chloride (400 ml) was stirred at 10°, pyridine (5.66 ml) was added followed by the slow dropwise addition of acetic anhydride (6.6 ml) in methylene chloride (10 ml). Solution soon resulted and the reaction mixture was then stirred for two hours whilst allowing the temperature to rise slowly to room temperature. The reaction mixture was washed with water (100 ml), 2N HCl (100 ml) and then water again (100 ml), dried (MgSO 4 ) and evaporated to give the title compound as a quarter-hydrate, (14.03 g), m.p. 139°-140°. Analysis %: Found: C, 63.51; H, 6.69; N, 6.07; Calculated for C 12 H 15 NO 3 .1/4H 2 O: C, 63.84; H, 6.92; N, 6.21. The tetrahydroisoquinoline hydrochloride starting material is described in J. Org. Chem., vol. 30, July 1965, pages 2247-2250. An alternative preparation of the title compound is described in J. Org. Chem., Vol. 36, no. 20, 1971, pages 3006-3010. PREPARATION 2 N-Acetyl-7-hydroxy-6-methoxy-1,2,3,4-tetrahydroisoquinoline ##STR6## 7-Hydroxy-6-methoxy-1,2,3,4-tetrahydroisoquinoline hydrochloride (2.60 g) was dissolved in water and the solution was basified to pH9 with concentrated (0.88) aqueous ammonia. The free base was extracted with methylene chloride/ethanol (9:1) (3×200 ml). The organic extracts were combined, washed (H 2 O), dried (MgSO 4 ) and evaporated to dryness. The residue was azeotroped with methylene chloride, evaporated, and the residue was suspended in methylene chloride (100 ml). Pyridine (1.05 ml) was added dropwise at 10° followed by acetic anhydride (1.25 ml) and the resulting mixture was allowed to stand over a weekend (about 68 hours). The solution was washed with 2N HCl, then with water, dried (MgSO 4 ) and evaporated. Medium pressure chromatography on silica (Merck "Art.9385") eluting with methylene chloride containing gradually increasing amounts of methanol (0-3%) followed by collection and evaporation of appropriate fractions gave the title compound as a quarter-hydrate (1.05 g), m.p. 142°-144°. Analysis %: Found: C, 63.49; H, 6.50; N, 5.96; Calculated for C 12 H 15 NO 3 .1/4H 2 O: C, 63.84; H, 6.92; N, 6.21. The tetrahydroisoquinoline hydrochloride starting material is described in J. Org. Chem., vol. 30, July 1965, pages 2247-2250. An alternative preparation of the title compound is described in J. Org. Chem., vol. 36, no. 20, 1971, pages 3006-3010. PREPARATION 3 N-Acetyl-6-benzyloxy-7-methoxy-1,2,3,4-tetrahydroisoquinoline ##STR7## N-Acetyl-6-hydroxy-7-methoxy-1,2,3,4-tetrahydroisoquinoline quarter-hydrate (14.0 g) was dissolved in methylene chloride (200 ml). Benzyl bromide (22.6 ml) was then added, followed by the addition of a solution of potassium hydroxide (4.62 g) in water (200 ml) and then tetra-n-butylammonium bromide (2.04 g). The resulting mixture was stirred vigorously overnight (16 hours). The organic layer was then separated, washed (H 2 O), dried (MgSO 4 ) and evaporated. Medium pressure chromatography of the residue on silica (Merck "Art.9385") eluting with methylene chloride containing gradually increasing amounts of methanol (0-10%) gave, after collection and evaporation of appropriate fractions, the title compound as a semi-solid which was recrystallised from ethyl acetate to give the pure title compound, 16.84 g, m.p. 125°-6°. Analysis %: Found: C, 73.05; H, 6.56; N, 4.42; Calculated for C 19 H 21 NO 3 : C, 73.29; H, 6.80; N, 4.50. PREPARATION 4 N-Acetyl-7-benzyloxy-6-methoxy-1,2,3,4-tetrahydroisoquinoline, m.p. 105°, was prepared similarly to the previous Preparation, starting from the corresponding 7-hydroxy-1,2,3,4-tetrahydroisoquinoline, benzyl bromide, aqueous potassium hydroxide and tetrabutylammonium bromide. Analysis %: Found: C, 72.02; H, 6.89; N, 4.29; Calculated for C 19 H 21 NO 3 .1/4H 2 O: C, 72.24; H, 6.86; N, 4.43. PREPARATION 5 N-(1-[6-Benzyloxy-7-methoxy-1,2,3,4-tetrahydroisoquinol-2-yl]ethylidene)-2-cyano-4,5-dimethoxyaniline ##STR8## The free base of 2-cyano-4,5-dimethoxyaniline (see J. Amer. Chem. Soc., 68, page 1903 [1946]) was prepared by dissolving the hydrochloride in saturated aqueous sodium bicarbonate solution to pH 8, extracting with methylene chloride, washing the organic extract with water, drying (MgSO 4 ) and evaporating. Medium pressure chromatography of the residue on silica (Merck "MK.9385") eluting with methylene chloride followed by collection and evaporation of appropriate fractions gave the pure free base. Phosphorus oxychloride (3.24 ml) was added over 1 minute to a stirred solution of N-acetyl-6-benzyloxy-7-methoxy-1,2,3,4-tetrahydroisoquinoline (10 g) in methylene chloride (100 ml) at 10°. After stirring for twenty minutes at room temperature, a solution of 2-cyano-4,5-dimethoxyaniline (5.72 g) in methylene chloride (80 ml) was added and the resulting suspension was heated at reflux for 16 hours. The reaction mixture was then allowed to cool, water (60 ml) was added followed by 40% sodium hydroxide to pH 8-9 with stirring for five minutes. The organic layer was then separated and the aqueous phase extracted with methylene chloride (3×50 ml). The combined organic layers were washed (H 2 O), dried (MgSO 4 ) and evaporated. The residue was chromatographed on silica (Merck Art.9385) under medium pressure, eluting with methylene chloride containing gradually increasing amounts of methanol (0-10%). Some impure product-containing fractions were re-chromatographed on silica but using methylene chloride containing 2-4% methanol. The pure product-containing fractions were combined, evaporated, and the residue recrystallised from ethyl acetate to give the title compound as a colourless powder (11.02 g), m.p. 164°-5° (d). Analysis %: Found: C, 71.46; H, 6.18; N, 9.15; Calculated for C 28 H 29 N 3 O 4 : C, 71.32; H, 6.20; N, 8.91. PREPARATION 6 N-(1-[7-Benzyloxy-6-methoxy-1,2,3,4-tetrahydroisoquinol-2-yl]ethylidene)-2-cyano-4,5-dimethoxyaniline The title compound, m.p. 72°-3°, was prepared similarly to the procedure of the previous Preparation, starting from N-acetyl-7-benzyloxy-6-methoxy-1,2,3,4-tetrahydroisoquinoline, phosphorus oxychloride, and 2-cyano-4,5-dimethoxyaniline. Analysis %: Found: C, 71.04; H, 6.16; N, 8.64; Calculated for C 28 H 29 N 3 O 4 : C, 71.32; H, 6.20; N, 8.91.
Novel 4-amino-6,7-dimethoxy-2-(6,7-disubstituted-1,2,3,4-tetrahydroisoquinol-2-yl)quinoline compounds have been prepared, including their pharmaceutically acceptable salts and various novel key intermediates therefor. These compounds are useful in therapy as anti-arrhythmic agents and therefore, are of value in the treatment of various cardiac arrhythmias. Preferred compounds include 4-amino-6,7-dimethoxy-2-(6-hydroxy-7-methoxy-1,2,3,4-tetrahydroisoquinol-2-yl)quinoline and 4-amino-6,7-dimethoxy-2-(7-hydroxy-6-methoxy-1,2,3,4-tetrahydroisoquinol-2-yl)quinoline. Methods for preparing these compounds from known starting materials are provided.
2
BACKGROUND OF THE INVENTION The present invention relates generally to heating ventilation and air conditioning systems (HVAC); and more particularly, it relates to a device for mounting air diffusers and their matching forced air boxes within orifices in floors, ceilings, and walls. One of the most common ways to conduct heated or cooled forced air from a furnace or air conditioning unit is by forcing the air through flexible ducts. The terminal ends of the ducts are connected to boxes positioned adjacent orifices in the room partitions leading to the interior of the room to be heated or cooled. The orifices are typically covered by diffusers or grates within the room interior which are attached to both the room partition and to flanges on the boxes. During installation of a diffuser and its matching box, an installer typically aligns the box with an orifice cut into a partition forming a floor, ceiling, or wall. The box must be held in position on the exterior side of the partition while a second person, positioned on the room side of the partition, drives screws through holes in the diffuser face, through the partition and into flanges on the box. The first person then attaches a flexible duct to the box. This is relatively simple to perform but is very time consuming since two people are needed to perform the installation. In addition, it is common to place HVAC diffusers in ceiling and walls constructed of materials such as drywall, plaster board, and the like. These materials do not accept screws because they are fabricated from calcined compositions which crumble when subjected to a twisting threaded motion as a result of which then form threadless holes or cause the orifice periphery to break away. Thus, screws extending from the diffuser which are driven through a portion of a dry wall partition and into a box flange are only secured to the box flange and are not fixed to the partition. Repeated removal and reattachment of screws driven into the partition periphery, necessitated by cleaning, painting of the room, and the like often result in enlargement of the orifice in the partition and subsequent inability of the user to remount the diffuser and box to the partition. A need, therefore, exists for a device which holds the box in place so only one person is needed to attach the diffuser to the box and to mount the diffuser and box to the partition orifice. A need also exists for a device which provides a secure attachment of the diffuser and box to the partition material and which inhibits the partition from crumbling. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a device which allows one person to install air diffusers and boxes in orifices in room partitions without the assistance of another person. It is also an object of the present invention to provide a secure means of attaching forced air diffuser and register boxes to partitions. Briefly, these and other objects and aspects of the invention are accomplished by a generally S-shaped device for mounting an air diffuser and a box attachable to said air diffuser in a room partition orifice, said device comprising a generally U-shaped bracket comprised of a.) a first panel; b.) a base plate attached to said first panel, and c.) a second panel attached to said base plate; and a resilient flange attached to said second panel of said generally U-shaped bracket. The bracket is attachable to the periphery of a room partition defining an orifice and is attachable to an air diffuser and the diffuser's matching box. The device flange permits entry of a box into a partition orifice and hinders withdrawal of the box from the orifice by spring tension between the device flange and the second panel of the bracket caused by the flange being flexed by the box. The device flange also forces the second panel of the device to accept piercing by screws by spring tension between the flange and the second panel of the device caused by insertion of the box into the partition orifice. The device thereby allows one person to mount the diffuser and box to a partition orifice without the assistance of another person. The generally U-Shaped bracket of the generally S-shaped device also protects the partition periphery from crumbling during insertion and removal of the screws attaching the diffuser to the box, to the partition and to the device, thereby providing a very stable and secure means for mounting the diffuser and box to the partition. Other objects, features, and advantages of the invention will become more apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the invention installed in an orifice in a room partition and attached to a diffuser and a box. FIG. 2 is a perspective view of the invention. FIG. 3 is an exploded perspective view of the invention as installed in FIG. 1. FIG. 4 is a partially cut-away sectional view of the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings wherein like characters designate like or corresponding parts throughout the several views, FIG. 1 illustrates a device 10 attached to a box 20, installed on a room partition 30, and attached to a diffuser 40. Box 20 is attached to flexible duct 50. The word "partition" is defined herein as any construction material such as wallboard, plaster, drywall, or the like which define a wall, or a ceiling. FIG. 2 illustrates the construction of device 10. Device 10 is comprised of a U-shaped bracket shown generally as 11 and a resilient flange 15. Bracket 11 is comprised of a first panel 12, a base plate 13, and a second panel 14. Second panel 14 and first panel 12 are approximately parallel to each other and approximately perpendicular to base plate 13 giving bracket 11 a generally U-shape and flange 15 forms an acute angle with second panel 14 giving an overall S-shape to device 10. Device 10 is utilized as shown in FIGS. 1, 3, and 4. With reference to FIG. 3, at least one and preferably two device 10's are attached to sections of a room partition periphery 31 which define an orifice 60 in a room partition 30 forming a part of a ceiling or wall. Two device 10's are shown in FIG. 3; however, more than two device 10's can be utilized as needed depending on the size and shape of the diffuser and box to be mounted. Box 20 is pushed into orifice 60 adjacent the two device 10's until flanges 21 on box 20 contacts periphery 31 of partition 30 and first panels 12 on each device 10, while sides 22 of box 20 contact and flex flanges 15 away from base plate 13 on each device 10. Flanges 15 are resilient and serve two purposes. The flanges 15 allow box 20 to be slid into orifice 60 but hinder the withdrawal of box 20 from orifice 60. Withdrawal of box 20 can be achieved by prying flanges 15 away from sides 22 and pushing box 20 back through orifice 60 in the reverse direction in which box 20 entered orifice 60. Box 20 is thus held within orifice 60 by one or more device 10's without a person on the duct side 32 of partition 30 holding box 20. Flanges 15 also provides a reinforcing pressure in the opposite direction of screw 70 as shown in FIG. 4 due to the box sides 22 flexing flanges 15 away from base plates 13. A lone installer on the room side 33 of partition 30 can thus position diffuser 40 against flanges 21 of box 20 and attach diffuser 40 to box 21 by driving screws through holes 80 in diffuser 40, through flanges 21, first panel 12, partition periphery 31, and through second panel 14 without requiring the assistance of another person to hold box 20 in place. Device 10 also provides the user with a very secure means to mount the diffuser and box within a partition orifice by providing screw attachment from the diffuser to flanges on the box, and to both first and second panels on the device which brackets the partition periphery 31. This is best shown by FIG. 4. The bracket covers the exterior and room sides of the periphery, thus, inhibiting enlargement of the screw holes through the periphery and thereby inhibiting the periphery 31 from crumbling and enlarging orifice 60. Panels 12 and 14 can have pre-drilled holes to engage screws 70 or the installer can simply create holes in panels 12 and 14 during screw installation. The lone installer can then enter the space on the duct side 32 of partition 30, typically in a basement, crawlspace, attic, or the like and attach duct 50 to duct attachment section 23 on box 20. The method of attaching a forced air duct to a box, a box to a diffuser, and a diffuser and box to an orifice in a room partition comprises the steps of a.) attaching at least one and preferably at least two generally S-shaped devices each comprising a bracket comprised of a first panel, a base plate attached to the first panel, and a second panel attached to the base plate, and a resilient flange attached to the second panel of the bracket to a the peripheral edge of a room partition defining an orifice; b.) inserting a box into the orifice and adjacent the device or devices of step a.) such that the device or devices hold the box within the orifice; c.) attaching a diffuser to the box, to the device or devices, and to the room partition; and d.) attaching a forced air duct to the box. Thus, the device allows one person to install forced air ducts to boxes, and boxes to diffusers within orifices in room partitions without the assistance of a second person. The device also provides a very secure means to mount diffusers and boxes to partitions which decreases the danger that the edges of the partition will crumble and enlarge the orifice in the partition. The device can also be utilized to mount diffusers and boxes to orifices in ceilings, walls, and floors formed by partitions constructed of rigid materials such as wood and cement. Rigid partitions do not require the use of a bracket to prevent enlargement of the partition orifice; however, the device is useful for allowing one person to install the diffusers and boxes to the rigid partitions. It will be understood, of course, that changes in the details and arrangement of steps and parts which have been described and illustrated herein in order to explain the nature of the invention, may be made by those skilled in the art without departing from the principles and scope of the invention as expressed in the appended claims.
The invention is a bracket having a resilient flange. The bracket attaches to the periphery of a room partition defining an orifice. The bracket provides a secure mounting location for an air diffuser and holds the box associated with the diffuser firmly in place allowing one person to install the diffuser and the box within an orifice.
8
TECHNICAL FIELD [0001] The present invention relates generally to fuel vapor storage canisters, and more specifically, to a fuel vapor storage canister having a volume compensator comprising an air-permeable, resilient polymeric foam. BACKGROUND [0002] Fuel vapor storage canisters are standard pieces of automotive equipment used to reduce engine emissions. See U.S. Pat. No. 3,683,597, “Evaporation Loss Control” issued Aug. 15, 1972 to Thomas R. Beveridge and Ernst L. Ranft. The fuel vapor storage canister receives and stores fuel vapors emitted from the fuel tank of the engine. Generally, these canisters contain a vapor adsorbent media, usually activated carbon, usually in the form of activated charcoal. The canister is designed to receive the emitted fuel vapors, and to store these vapors. During engine operation, the stored fuel vapors may be purged from the fuel canister into the engine induction system for consumption within the engine. The greatest quantity of fuel vapor is emitted from the fuel tank immediately after engine shutdown. Vapors are also emitted from the fuel tank to the canister as a result of diurnal losses. [0003] The basic design for fuel vapor storage canisters is well established. It includes an elongated canister housing often of generally rectangular cross section. The housing typically has a flexible construction, which can compensate for expansion caused by environmental conditions. A plastic or nylon housing is typical. The canister housing typically has several internal components including a fuel vapor adsorbent bed of packed activated carbon, an outlet carbon filter, and a volume compensator, which is located at the bottom of the canister housing. [0004] Volume compensators serve two important functions in the fuel vapor canister. First, a volume compensator limits the shifting of the activated carbon particles in the carbon bed, which can cause the particles to erode. Because the canister frequently encounters vibration and other motion, ineffective packing of the carbon bed can result in shifting of the carbon particles, which produces surface erosion. As carbon particles erode against each other flow paths may be left behind through which hydrocarbons can escape without being adsorbed. Accordingly, volume compensators are used to ensure tight packing in the carbon bed and thereby limit the effect of vibration in the carbon bed. Second, the volume compensator helps maintain the internal area of the carbon bed as the canister body expands or contracts due to temperature changes. Changes in the internal area of the carbon bed can also result in the shifting or erosion of the carbon particles. Accordingly, volume compensators are used to minimize the effect of thermal expansion by resiliently compacting the carton bed. [0005] The design of volume compensators has undergone many modifications over the past 40 years. Early fuel vapor storage canisters did not include a volume compensator. An early embodiment of a volume compensator was an assembly of two molded trays separated by springs. See U.S. Pat. No. 5,098,453, “Vapor Storage Canister with Volume Change Compensator” issued Mar. 24, 1992 to Turner et al. The current volume compensators typically include a plastic separator or grid, filter media (usually a closed pore polyester foam), springs, and a screen to prevent the carbon from penetrating into the filter media. The springs are used to compensate for the changes in carbon volume during vehicle operation. See U.S. Pat. No. 6,551,388, Volume Compensator Assembly for Vapor Canister to Oemcke et al. SUMMARY [0006] The present invention uses an air-permeable, resilient, polymeric foam, rather than a mechanical spring, as a volume compensator. In one embodiment, the foam is an open pore foam, also referred to as an open cell foam. BRIEF DESCRIPTION OF THE DRAWINGS [0007] FIG. 1 is a cross-sectional view of a prior art fuel vapor canister with multi-component volume compensator. [0008] FIG. 2 is a cross-sectional view of a fuel vapor canister in accordance with one embodiment of the present invention. [0009] FIG. 3 is a schematic cross-sectional view of an open pore polyurethane foam utilized in the preferred embodiment of the present invention. DETAILED DESCRIPTION [0010] FIG. 1 illustrates a prior art fuel vapor canister with a multi-component volume compensator. At the top of the canister 10 is a first tube 11 connected to a fuel tank, a second tube 13 connected to a purge line, and a third tube 12 that vents to the atmosphere. The tube 11 delivers air-containing fuel vapors from the fuel tank to an activated carbon medium 14 within the canister 10 . During engine operation, the fuel vapors may be purged from the fuel canister 10 to the engine through the tube 13 . The activated carbon medium 14 is supported and compacted by a multi-component volume compensator, which may include a metal screen 15 , a filter media 16 , a plastic grid 17 , and springs 18 . In addition, there is an end plate 19 located on the bottom of the canister 10 for canister sealing. A partition or baffle 20 may be placed in the canister to prevent vapors from passing out tube 12 without first circulating through the carbon bed 14 for absorption. [0011] The metal screen 15 and filter media 16 form a movable base that contains and compacts the carbon in the activated carbon medium 14 . The grid 17 provides a rigid surface against which the springs 18 can exert a compaction force. In conventional fuel vapor canisters, the filter media 16 may be a closed pore or high density open pore polyurethane and the screen 15 may be a fine metal mesh screen. The plastic grid 17 may be any rigid material including plastic and the springs 18 may be mechanical springs such as helical wire compression springs. Some manufacturers of the volume compensator device leave out the screen and/or filter media altogether. [0012] FIG. 2 illustrates a structure in accordance with one embodiment of the present invention. The canister housing 40 includes inlet 41 and outlet 42 tubes, an activated carbon medium 43 , a foam volume compensator 44 , an end plate 45 and a partition 46 . Air containing fuel vapors may be delivered to the carbon medium 43 and purged to the engine for consumption through tube 41 . In another embodiment, separate inlet and purge lines may be used as in the prior art device. [0013] The foam 44 is resilient and maintains the positioning of the activated carbon medium 43 inside the canister housing 40 . When the foam 44 is compressed, the foam 44 provides a compaction force that acts against the activated carbon medium to stabilize the medium 43 as discussed above. Furthermore, the foam 44 is air-permeable to facilitate airflow through the canister and minimize pressure drops. [0014] FIG. 3 provides an enlarged schematic view of an open pore foam used in the fuel vapor storage canister in one embodiment of the invention. Preferably, the foam is a low density open pore polyurethane foam. As depicted in FIG. 3 , the open pore structure provides numerous flow paths through the foam resulting in good air-permeability. The foam can be fabricated with various pore sizes, which enables the foam to be useful in numerous applications. Pore sizes may range from about 25 to 65 ppi. The versatility of pore size and the open pore structure enables the foam to control permeability and airflow. Low density open pore foams provide increased permeability over the closed pore and high density open pore foams employed in the prior art. Further, the foam also provides other functionality such as filtering, sound/absorption, vibration dampening, etc. While polyurethane foams are desirable because of their chemical resistance and mechanical/elastomeric properties, those skilled in the art will recognize other commercially available foams may be used. [0015] In the fuel vapor storage canister, the pore size of the foam used will depend on the carbon medium characteristics. The invention incorporates 35 ppi foam in one embodiment in which 2 mm pelletized carbon is used in the canister, and utilizes 65 ppi foam in one embodiment when 18×36 mesh granular carbon is used. [0016] The variety of pore sizes in which the polyurethane foam is available provides fabrication and manufacturing versatility. In one embodiment the polyurethane foam has a density of about 1.7 to 2.1 lbs/ft3 and an indentation force deflection (IFD) of greater than or equal to 60 lbs. Indentation force deflection is defined herein as the pounds of force necessary to compress a foam sample 25%, i.e., to 75% of its original thickness. One example of suitable foams are the flexible polyurethane foams produced by FOAMEX. [0017] The resiliency of the polyurethane foam 44 facilitates the stabilization of the carbon medium 43 in the fuel vapor storage canister housing 40 . During assembly of the canister, the foam is compressed between the end plate 45 and the carbon bed 43 to approximately 40 to 60% of its original thickness. In response, the foam exerts an opposing compression or compaction force on the carbon bed. This opposing force minimizes the effect of vibration and thermal expansion and contraction. [0018] All documents cited are, in relevant part, incorporated herein by reference. The citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention.
A fuel vapor storage canister comprising an elongate housing, an activated carbon bed, and a volume compensator of resilient, air-permeable foam. The foam volume compensator maintains the canister volume and the position of the activated carbon component, which enables proper adsorption of vapors in the fuel vapor storage canister.
5
CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims benefit of U.S. Provisional Application No. 60/266,958, filed Feb. 6, 2001. BACKGROUND OF THE INVENTION [0002] The present invention relates to infrared (IR) remote control vehicles having multiple body styles operable with a universal chassis with attachable dynamic assemblies, and more particularly to robotic vehicles that can accept one or more different weapon assemblies operable from the drive motors of the universal chassis. [0003] It would be desirable to provide a modular chassis system for children facilitating the customization or modification of overall vehicle designs and allowing for the configuration of robotic vehicles which may include mechanical subassemblies such as weaponry providing a play pattern as between remote control vehicles operable simultaneously such that overall functionality may be removed or limited based on collisions or damages taken on by the vehicles. SUMMARY OF THE INVENTION [0004] Briefly summarized, the present invention provides a universal chassis which may be assembled with modular componentry allowing for a play pattern with the user in which modification of the overall construction of the vehicle is encouraged. There is a desire therefore to provide for the ability to accept a variety of snap-on components. In operating the configured vehicle, two motors, i.e., left and right, are provided with pulsed controlled operation to facilitate two-speed performance. The ability to transmit/receive IR signals modulated on one or more of multiple carriers facilitates the play pattern with simultaneous operation of multiple vehicles. An impact sensor or the like provides for detecting impacts, and processor control may be used for counting impacts in order to modify the functionality accorded to the user with the universal chassis. [0005] Advantageously, snap-on mechanical subassemblies may be powered from either of the two motors of the universal chassis such that operation of either motor may operate the snap-on mechanical subassembly which may be provided as a weapon or the like as use by the robotic vehicle. The controller onboard the chassis controls all functionality of the chassis and may also provide for the detection of the presence or absence of any mechanical subassemblies. Additionally, interlocks or clutch mechanisms may be provided with the mechanical subassemblies for safety and reliability of the configured vehicles. BRIEF DESCRIPTION OF THE DRAWINGS [0006] A better understanding of the present invention is obtained when considered in connection with the following description, drawings and software Appendix (A-1 through A-8), in conjunction with the following figures, in which: [0007] [0007]FIG. 1 illustrates an exploded view of a basic universal chassis in accordance with the present invention; [0008] FIGS. 2 A- 2 J, FIGS. 3 A- 3 J, FIGS. 4 A- 4 J, and FIGS. 5 A- 5 J respectively illustrate four (4) robotic vehicle embodiments illustrating various subassemblies corresponding to associated assemblies as between the embodiments of the FIGS. 2 - 5 , with a total assembly illustrated as (A) and subassemblies (B)-(J); [0009] [0009]FIG. 6 is a schematic diagram of the transmitter electronics provided in a hand-held controller; and [0010] FIGS. 7 A- 7 C are schematic diagrams of the electronic circuitry in the universal chassis in which [0011] [0011]FIG. 7A shows the IR receiver circuitry and [0012] [0012]FIGS. 7B and 7C shows the H bridge motor control circuitry for the chassis motors in which FIG. 7B controls the left-hand motor and FIG. 7C controls the right-hand motor. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0013] With reference to FIG. 1, the universal chassis for the preferred embodiments is provided as an IR controlled vehicle chassis which facilitates multiple functionality including the provision of a dual motor, dual speed, remote control vehicles that accommodate multiple modular wheel, weapon and body assemblies which may be received on the universal chassis of FIG. 1. As described, the chassis is further equipped with on-board electronics for receiving encoded IR signals for controlling the speed of the left-hand and right-hand motors respectively, and microprocessor control is provided for counting the number of physical impacts as identified with an impact switch or tilt sensor. [0014] IR Battlebots are described as a variety of dual motor, dual speed, remote controlled vehicles having a universal chassis with the means for accepting modular wheel, weapon and body assemblies and where the chassis is also equipped with the on board electronics for receiving an IR signal, for controlling the speed of the motors, and for counting the number of physical impacts received. The controller has the means of transmitting via IR any one of 17 codes required for the operation of the vehicles. These functions are forward and reverse for both motors and “turbo” forward and reverse for both motors. There is also a code for when the vehicle is idle. The IR itself is broadcast at one specific carrier frequency. [0015] Both the chassis and the controller may be outfitted with a switch for changing the specific IR carrier broadcast frequency. The number possible switch positions is determined by the number of Battlebots (chassis) required to battle simultaneously. [0016] Alternatively, each Battlebot (chassis) may be tuned to a single specific IR carrier frequency. In this event, two of the same style Battlebots (chassis) will not be able to operate simultaneously. [0017] To clarify further, any chassis may become any Battlebot because of the modular nature of its construction. The modularity is purposely built in to allow users to modify their Battlebot chassis. [0018] A hand-held controller (not shown) is facilitated with the ability to transmit via IR signals nine codes which facilitate 17 operations of the motor as illustrated Appendix A-1 through A-8. The decoding of the 17 encoded operations for the motor drive combinations of the vehicles facilitates the functions of forward, reverse, and turbo drive commands for either or both motors including turbo forward and reverse for both motors. A code is also provided for indicating when the vehicle is in an idle state when the user has not manipulated the controls of the hand-held controller such that the vehicle motor may be provided in an OFF state. Additionally, the IR carrier frequency is broadcast by individual controllers at separate carrier frequencies allowing for the control and operation of multiple vehicles simultaneously by different users. [0019] To this end, the controller and the chassis may be outfitted with a switch, e.g., rotatable, momentary or dip switches, for changing the specific IR broadcast frequencies. The number of possible switch positions or frequency configurations may be determined by the number of vehicles required to battle or otherwise operate simultaneously. Alternatively, each chassis may be tuned to a single specific IR carrier frequency, in which two of the same style chassis may not be able to operate simultaneously. [0020] The configured vehicles are intended for operation at relatively close range with directional infrared IR controllers such that multiple players may engage in a battle or collision activity between multiple vehicles. The operation may be provided either on a tabletop or on a flat floor surface for providing a platform for engaging the play pattern as between the players and their controlled vehicles. It is likely that the players will be operating the vehicles within close range, e.g., 3 to 10 feet, preferably at a range of about six feet. As shown in FIG. 1, the universal chassis includes electronic circuitry on a circuit board including an IR receiver, impact switch, an LED indicator and reset button operable with batteries housed within the chassis. Each of two motors (left and right) have a combination gear which operates the driver train and weapon subassemblies. As discussed, the assemblies of FIGS. 2A, 3A, 4 A, and 5 A facilitate operation from either of the two motors that will activate the weapon subassemblies such that slider gears in FIGS. 2J, 3J, 4 J, and 5 J may individually operate the mechanical subassemblies attached to the universal chassis. [0021] As discussed, the universal chassis accepts modular components and includes four bosses to accept any of the four bodies, or body styles of FIGS. 2G, 3G, 4 G, and 5 G, identified by name by Minion, Blendo, Killerhurtz, and Vlad, body styles, respectively. The reversible motors are provided with two speeds either for pulsed operation from the information processor facilitated with a microprocessor or microcontroller, which controls the speed by providing a pulsed or alternatively a full power (“turbo”) operation. In addition to providing for slower pulsed operation, the pulsed operation of the motor also serves to extend the battery life of the vehicle, and the slow pulsed operation is also a provided mode of operation for steering or otherwise maneuvering the vehicles. [0022] The IR controller is operated on one of multiple carrier frequencies, at least three and preferably four to eight frequencies for allowing simultaneous operation, e.g., eight vehicles over eight carrier frequencies, which are controlled with a frequency configuration switch or input provided by the user. The infrared (IR) transmission link is somewhat directional with the remote hand-held controllers providing an angle of illumination of about 40 degrees allowing for multiple players in indoor closer range operation. The transmit and receive circuitries are described further below in connection with FIGS. 6 and 7A and 7 B which are provided with a conventional Winbond W583 encoding circuit which transmits signals over a carrier frequency generated with a 555 timer. [0023] The mechanical subassemblies are illustrated in exploded views for each of the four embodiments, as shown in FIGS. 2J, 3J, 4 J, and 5 J, respectively, providing a saw operation, a rotary dome with serrated teeth, a hatchet, and forklift type assemblies, however, various other active assemblies may be operable from the universal chassis. [0024] Turning now to FIG. 6, the Winbond W583 encoder circuit which is used both in the transmitter circuit of FIG. 6 and receiver circuit of FIG. 7A, provides for modulation as indicated in the hardware IR of Appendix A-1, which is facilitated with the software control IR transmitter program of Appendix A-2 through A-5 and the IR receiver program of A-6 through A-8. As shown in FIG. 6, the IR output of the W583 integrated circuit is coupled via a transmitter to the 555 timer, which outputs a modulated carrier frequency from a IR LED under the control of a switching transistor. Codes indicated in accordance with Appendix A-1 are thus transmitted from the transmitter circuitry of FIG. 6. The typical operation for the 555 timer provides a carrier output of approximately 38 kilohertz which may be varied for operation on multiple different carriers. [0025] With reference to FIG. 7A, the IR receiver includes a photo diode with a tuner adjustment stage (optional) followed by a two-stage operational amplifier for amplifying the detected IR signal which is presented to a phase-lock loop (PLL) tone decoder herein LM567 decoder which generates an output to the Winbond W583 integrated circuit for controlling the OR GATE operation of the H bridge motor circuitry of FIGS. 7B and 7C, which are provided as conventional motor drive circuits. It will be appreciated that the 555 timer of the FIG. 7A receiver provides gated operation such that the turbo decode output resets the 555 timer so as to provide full power operation to the motors via the control circuitry of FIGS. 7B and 7C. [0026] While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. [0027] VI.12.1 H/W IR Protocol [0028] The output protocol of hardware defined IR begins with a Start bit followed by 9 Data bits(1 data byte, MSB first, and 1 parity bit), and Stop bit. The Start bit is typically composed of 1 mS High(TH) and 6.5 mS Low(TL). Data bit ‘1’ is composed of 1 mS High and 4 mS Low. Data bit ‘0’ and Stop bit are composed of 1 mS High and 2 mS Low. It's called pulse position modulation. The IROUT pin will keep high in TH duration and output 38 KHz carrier with 75% duty cycle in TL duration. Receiver module will recover the original waveform by filtering the 38 KHz carrier out. Parameter Description Min. Typ. Max. Unit TD0 Data “0” period 3000 μS THD0 Data “0” high time 800 1000 1200 μS TLD0 Data “0” low time 1600 2000 2400 μS TD1 Data “1” period 5000 μS THD1 Data “1” high time 800 1000 1200 μS TLD1 Data “1” low time 3200 4000 4800 μS TSTR Start bit period 7500 μS THSTR Start bit high time 800 1000 1200 μS TLSTR Start bit low time 5200 6500 μS [0029] VI.13 CPU INTERFACE [0030] The W583xxx can communicate with an external microprocessor through a simple serial CPU interface. This ; Battle Bots ; ; BBot_T2  IR transmitter program ; ; ; ; W583S40   DEFPAGE 1 NORMAL   OSC_3MHZ   VOUT_DAC   LED0   FREQ2 32:   LD EN0,10111011b LD EN1,00110011b   LD R0,0 LD MODE0,10111111B ;STP C control IR LD MODE1,0FEH ;IR carrier disabled END 0: ;TG1 is low ;ignore TG2 [10] JP 40@TG6_LOW JP 41@TG4_LOW JP 42@TG5_LOW ; LD STOP,11111011b ; [500] ; LD STOP,11111111b ; [500] ; LD STOP,11111011b ; [500] ; LD STOP,11111111b ; [500] ; LD STOP,11111011b ; [500] ; LD STOP,11111111b ; [500] ; LD STOP,11111011b ; [500] ; LD STOP,11111111b ; [500] LD R0,33 ;left turn JP 110 1: ;ignore TG1 ;TG2 is low [10] JP 45 9: ;TG6 is low ;ignore TG4 [10] JP 40@TG1_LOW JP 49@TG2_LOW 3: ;ignore TG6 TG4 is low [10] JP 41@TG1_LOW JP 50@TG2_LOW JP 47 4: ;TG1 returns high [10] JP 45@TG2_LOW JP 46@TG6_LOW JP 47@TG4_LOW LD R0,49 ;stop JP 110 5: ;TG2 returns high [10] JP 0@TG1_LOW JP 46@TG6_LOW JP 47@TG4_LOW LD R0,49 ;stop JP 110 13: ;TG6 returns high [10] JP 0@TG1_LOW JP 45@TG2_LOW JP 47@TG4_LOW LD R0,49 ;stop JP 110 7: ;TG4 returns high [10] JP 0@TG1_LOW JP 45@TG2_LOW JP 46@TG6_LOW LD R0,49 ;stop JP 110 8: ;TG5 is low [10] JP 0@TG1_LOW JP 45@TG2_LOW JP 46@TGG_LOW JP 47@TG4_LOW LD R0,49 ;stop JP 110 12: ;TG5 returns high [10] JP 0@TG1_LOW JP 1@TG2_LOW JP 9@TG6_LOW JP 3@TG4_LOW LD R0,49 ;stop JP 110 40: ;TG1 is low ;TG6 is low JP 43@TG5_LOW LD R0,40 ;forward JP 110 41: ;TG1 is low ;TG4 is low JP 44@TG5_LOW LD R0,37 ;ccw spin JP 110 42: ;TG1 is low ;TG5 is low LD RO,41 ;turbo left turn JP 110 43: ;TG1 is low ;TG6 is low ;TG5 is low LD R0,48 ;turbo forward JP 110 44: LD R0,45 ;turbo ccw spin JP 110 45: ;TG2 is low JP 49@TG6_LOW JP 50@TG4_LOW JP 51@TG5_LOW LD R0,34 ;reverse left turn JP 110 46: ;TG1 is high ;TG2 is high ;TG6 is low JP 54@TG5_LOW LD R0,35 ;right turn JP 110 47: ;TG1 is high ;TG2 is high ;TG6 is high ;TG4 is low JP 55@TG5_LOW LD R0,36 ;reverse right turn JP 110 48: ;TG1 is high ;TG2 is high ;TG6 is high ;TG4 is high ;TG5 is low LD R0,49 ;stop JP 110 49: ;TG2 is low ;TG6 is low JP 52@TG5_LOW LD R0,38 ;cw spin JP 110 50: ;TG2 is low ;TG4 is low JP 53@TG5_LOW LD R0,39 ;reverse JP 110 51: ;TG2 is low LD R0,42 ;turbo reverse left turn JP 110 52: ;TG2 is low ;TG6 is low ;TG5 is low LD R0,46 ;turbo cw spin JP 110 53: ;TG2 is low ;TG4 is low ;TG5 is low LD R0,47 ;turbo reverse JP 110 54: ;TG1 is high ;TG2 is high ;TG6 is low ;TGS is low LD R0,43 ;turbo right turn JP 110 55: ;TG1 is high ;TG2 is high ;TG6 is high ;TG4 is low ;TG5 is low LD R0,44 ;turbo reverse right turn JP 110 110: [300] TX R0 [100] TX R0   ;[1000] [400] JP 110 2: 60: 100: 10: 11: 6: 14: 15: ... 255: jp 32 ; Battle Bots ; ; BBOT_R2  IR receiver program ; ; ; ; W583S40 DEFPAGE 1 NORMAL OSC_3MHZ VOUT_DAC LED0 FREQ2  ;8KHZ POI:   LD EN0,0   LD EN1,0 ;   LD MODE0,0bFH ; LD MODE0,00111111b ;led1 DC,stpc output LD MODE0,00101111b ;led1 DC,stpc output,short debounce ;   LD MODE1,0FFH LD MODE1, 11111111b ;   LD STOP,0FFH   LD STOP,07FH LED1  ;;led1 on   [400] ;   LD EN0,00H LD EN1,00001000b ;TG8 negative edge triggered for jiggle switch ; LD EN1,00000000b ;TG8 negative edge triggered for jiggle switch DISABLED LD R0,50   JP 100 11: JP R0 100:   [880] LD STOP,011111111b JP 101 END 101:   [880] LD STOP,01111111b JP 102 END 102:   [880] LD STOP,01111111b JP 103 END 103:   [880] LD STOP,01111111b JP 104 END 104:   [880] LD STOP,01111111b JP 105 END 105:   [880] LD STOP,01111111b JP 106 END 106:   [880] LD STOP,01111111b JP 107 END 107:   [880] LD STOP,01111111b JP 108 END 108:   [880] LD STOP,01111111b JP 109 END 109:   [880] LD STOP,01111111b   JP 100 END 33: LD STOP,01111110b JP 100 34: LD STOP,01111101b JP 100 35: LD STOP,01011111b JP 100 36: LD STOP,01110111b JP 100 37: LD STOP,01110110b JP 100 38: LD STOP,01011101b JP 100 39: LD STOP,01110101b JP 100 40: LD STOP,01011110b JP 100 41: LD STOP,01101110b JP 100 42: LD STOP,01101101b JP 100 43: LD STOP,01001111b JP 100 44: LD STOP,01100111b JP 100 45: LD STOP,01100110b JP 100 46: LD STOP,01100101b JP 100 47: LD STOP,01100101b JP 100 48: LD STOP,01001110b JP 100 49: LD STOP,01111111b JP 100 50: LD EN1,00000000b ;disable all triggers LD STOP,11111111b ;disable IR input - npn base hi...npn on! LD R0,51 LED1 [1000] LD STOP,01111111b LD EN1,00001000b ;TG8 negative edge triggered for jiggle switch JP 100 51: LD EN1,00000000b ;disable all triggers LD STOP,11111111b ;disable IR input - npn base hi...npn on! LD R0,52 LD MODE0,10111111b ;led1 flash LED1 [1000] LD STOP,01111111b LD EN1,00001000b ;TG8 negative edge triggered for jiggle switch JP 100 52: LD EN1,00000000b ;disable all triggers LD STOP,11111111b ;disable IR input - npn base hi...npn on! LED0 ;led1 off 53: JP 53
A universal chassis which may be assembled with modular componentry allowing for a play pattern with the user in which modification of the overall construction of the vehicle is encouraged. The modularity is purposely built in to allow users to modify their Battlebot chassis. In operating the configured vehicle, two motors, i.e., left and right, are provided with pulsed controlled operation to facilitate two-speed performance. The ability to transmit/receive IR signals modulated on one or more of multiple carriers facilitates the play pattern with simultaneous operation of multiple vehicles. An impact sensor or the like provides for detecting impacts, and processor control may be used for counting impacts in order to modify the functionality accorded to the user with the universal chassis. The mechanical subassemblies (such as weaponry providing a play pattern as between remote control vehicles operable simultaneously such that overall functionality) may be removed or limited based on collisions or damages taken on by the vehicles.
0
TECHNICAL FIELD This invention is directed to an apparatus and method of controlling the environment disposed about a transition joint between two vessels for conveying molten glass, and particularly an expansion joint between two non-contacting conduits. BACKGROUND One method of forming a thin sheet of glass is by a drawing process where a ribbon of glass is drawn from a reservoir of molten glass. This may be accomplished, for example, via a down-draw process (e.g. slot or fusion), where the ribbon is drawn downward, typically from a forming body. Once the ribbon is formed, individual sheets of glass are cut from the ribbon. In a conventional downdraw process, the molten glass is formed by melting precursor, or batch materials in a melting furnace. The molten glass is then flowed through various other components, such as fining vessels and stirring vessels. Eventually, the molten glass is conveyed to the forming body where the molten glass is formed into a continuous ribbon of glass. The ribbon may thereafter be separated into individual panes or glass sheets. The transfer apparatus for molten glass from the upstream portions of the conveying system to the forming body is particularly important, and must be capable of balancing many needs, such as the thermal expansion of the different materials of the system. For example, in the case of a fusion-type downdraw process, the forming body is typically a refractory material (e.g. a ceramic), that has a different thermal expansion characteristic than the principally platinum or platinum alloy vessels preceding it. To that end, the connection between the preceding system and the forming body inlet are typically free-floating, in the sense that the inlet conduit and the feed conduit are not directly joined, but instead ride one within the other without direct contact. Nevertheless, there is a need to provide a seal between the feed and inlet conduits. SUMMARY In a delivery system for conveying molten glass to a forming apparatus to produce high purity glass articles, such as glass for optical components (e.g. optical lenses) and liquid crystal display substrates, the vessels used to convey the molten glass are often formed from a oxidation resistant metal capable of withstanding prolonged exposure to very high temperatures, sometimes in excess of 1600° C. Certain platinum group metals are ideal for such applications, particular platinum group metals such as platinum, rhodium, and alloys thereof (e.g. alloys containing from 70%-80% platinum and 30%-20% rhodium). Since the delivery system is formed of metal vessels (e.g. conduits), the delivery system is typically rigidly connected and supported, and even small displacement can cause damage to the vessels and/or disruption to the forming process. This is particularly true in the case of vessels comprising platinum, since the high cost of the metal drives the need to make the vessels as thin as possible. Unfortunately, certain components of the delivery and/or forming apparatus must be capable of movement. For example, certain components of the delivery and/or forming apparatus may be comprised of different materials with different thermal expansion characteristics. During heat up or cool down of the system or apparatus, the differential expansion can result in relative movement of the components that must be accommodated. In addition, one or more of the components may be intentionally moved. For example, in a fusion-type process for forming glass sheets, the molten glass is flowed over exterior forming surfaces of a forming body. The forming body may, from time to time, be tilted to adjust the mass flow rate over the forming body. Thus, the delivery system must be capable of accommodating this motion without damage to the system components. To provide a flexible non-contact joint between portions of the delivery system and/or forming apparatus, it has been the practice to nest at least a portion of one vessel inside another vessel in a manner such that the first vessel does not contact the second vessel. For example, the end of a first conduit (pipe) may be inserted into the opening of another downstream conduit (pipe), wherein a gap separates the first and second conduits, and the molten glass is flowed from the first conduit into the second conduit. However, the gap provides a free surface to the molten glass that is exposed to the ambient atmosphere. Because of the large temperature differentials associated with the delivery system and surrounding apparatus, thermally induced drafts can cause the formation of gaseous inclusions (blisters) in the molten glass that are then transported to the forming apparatus and incorporated into the formed glass article. As described herein, a flexible barrier is proposed that forms a gas tight seal around the vessel-to-vessel non-contact joint and isolates the atmosphere to which the molten glass free surface is exposed). The flexible barrier allows movement of one vessel of the joint without influencing the position of the other vessel of the joint, and facilitates conditioning of the atmosphere in contact with the molten glass free surface independently from the ambient atmosphere. In accordance with one embodiment, an apparatus for sealing a gap between vessels conveying molten glass comprises a first conduit having an open distal end and a second conduit having an open distal end. At least a first portion of the first conduit adjacent the first conduit distal end is disposed within the second conduit without contacting the second conduit. A gap is disposed between the first conduit and the second conduit that exposes a free surface of the molten glass in the second conduit to a first atmosphere. The apparatus further comprises a flexible barrier disposed about a second portion of the first conduit, wherein the second portion extends from the second conduit open distal end. A first sealing flange is joined to the first conduit and a second sealing flange is joined to the second conduit. The flexible barrier, the first sealing flange and second sealing flange comprise a gas-tight seal that separates the first atmosphere from an ambient atmosphere disposed about an exterior of the flexible barrier. The flexible barrier may be, for example, a bellows. In some embodiments, the first and second flanges each comprise an inner ring and an outer ring joined to the respective inner ring. That is, the outer ring is joined about a periphery of the inner ring. The outer ring and the inner ring may, for example, be welded together. In certain embodiment the inner ring of both the first conduit and the second conduit flanges comprises platinum. The inner ring may be a platinum alloy, such as a platinum rhodium alloy. The first and second conduits may also comprise platinum. To prevent the generation of galvanic electrical currents, the flexible barrier is electrically isolated from the first and second conduits. Moreover, the inner ring of the either or both of the first or second flanges is non-planar, having instead an undulation (deviation from planarity) that accommodates movement of the respective associated conduit by flexing of the respective flange. Preferably, the first atmosphere in contact with the molten glass free surface is different than the second atmosphere. For example, the apparatus may include a control system for varying a hydrogen partial pressure of the first atmosphere. The flexible barrier is preferably formed from a material capable of withstanding exposure to temperatures in excess of 500° C. for at least two months without significant deterioration. For example, a suitable material for the flexible barrier is stainless steel comprising nickel or chromium. In some instances, for example if either the first or second conduits is directly heated by flowing an electrical current through one or both of the conduits, is preferable that the flexible barrier is non-magnetic to prevent the generation of electrical eddy current. To prevent the flow of galvanic currents between the conduits and subsequent generation of oxygen bubbles within the molten glass, the first and/or second conduit is electrically isolated from electrical ground. In another embodiment, a method of making a glass article is described comprising producing a molten glass and conveying the molten glass from a first vessel to a second vessel. The glass article may be, for example, a glass ribbon that can then be separated into individual glass sheets. At least a portion of the first vessel extends within the second vessel without contact with the second vessel, there being a free surface of the molten glass exposed to a first atmosphere in a gap between the first and second vessels. The first atmosphere is separated from an ambient atmosphere by a flexible metallic barrier coupled to the first and second vessels. The flexible barrier comprises a gas tight seal between the first and ambient atmospheres. The molten glass is flowed from the second vessel to a forming body to produce a glass article. The flexible barrier may, for example, comprise a bellows. The bellows includes pleats that allow for both expansion and contraction of the bellows. The flexible barrier is preferably electrically isolated from the first and second vessels to eliminate galvanic current flow between the first and second vessels. In some embodiments a partial pressure of hydrogen in the first atmosphere is controlled to prevent hydrogen permeation bubbles from being generated in the molten glass. In certain embodiments a first flange is joined to the first vessel and a second flange is joined to the second vessel, the first and second flanges being coupled to the flexible metallic barrier, and the first flange is electrically isolated from the second flange. In some processes, the second vessel may be moved relative to the first vessel, and the movement of the second vessel results in an extension or compression of the flexible metallic barrier. To control a temperature of the molten glass conveyed within the first vessel, the first vessel may be heated, such as through the use of external heating elements disposed proximate the first conduits wall, or by flowing an electrical current through the first vessel. The first atmosphere is separated from a second atmosphere by the first flange, and a hydrogen partial pressure of the second atmosphere may also be controlled. In some embodiments, a third atmosphere may be disposed about at least a portion of the second vessel and the third atmosphere is separated from the second atmosphere. A hydrogen partial pressure of the third atmosphere may also be controlled independently from the first and second atmospheres. The invention will be understood more easily and other objects, characteristics, details and advantages thereof will become more clearly apparent in the course of the following explanatory description, which is given, without in any way implying a limitation, with reference to the attached Figures. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the present invention, and be protected by the accompanying claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross sectional elevation view of an exemplary fusion downdraw process according to an embodiment of the present invention. FIG. 2 is a cross sectional view of a forming body comprising the apparatus of FIG. 1 . FIG. 3 is a cross sectional view of an exemplary sealing apparatus according to an embodiment of the present invention. FIG. 4 is a cross sectional view of a sealing flange according to an embodiment of the present invention showing an undulation for accommodating movement of a connected vessel. FIG. 5 is a top view of the sealing flange of FIG. 4 . DETAILED DESCRIPTION In the following detailed description, for purposes of explanation and not limitation, example embodiments disclosing specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one having ordinary skill in the art, having had the benefit of the present disclosure, that the present invention may be practiced in other embodiments that depart from the specific details disclosed herein. Moreover, descriptions of well-known devices, methods and materials may be omitted so as not to obscure the description of the present invention. Finally, wherever applicable, like reference numerals refer to like elements. In an exemplary fusion-type downdraw process, molten glass is produced in a melting furnace to which a batch material (e.g. various metal oxides or other constituents) is supplied. The molten glass is thereafter conditioned to remove bubbles, and then stirred to homogenize the glass. The molten glass is then supplied via a feed conduit to an inlet of a forming body comprising a channel open at its top formed in an upper surface of the body. The molten glass overflows the walls of the channel and flows down converging outside surfaces of the forming body until the separate flows meet at the line along which the converging surfaces meet (i.e. the “root”). There, the separate flows join, or fuse, to become a single ribbon of glass that flows downward from the forming body. Various rollers (or “rolls”) positioned along the edges of the ribbon serve to draw, or pull the ribbon downward and/or apply an outward tensioning force to the ribbon that helps maintain the width of the ribbon. Some rolls may be rotated by motors, whereas other rolls are free-wheeling. Although the melting furnace, or “melter” is typically formed from a refractory ceramic material (e.g. alumina or zircon), much of the downstream system for conveying and treating the molten glass is formed from a high temperature-resistant metal, such as platinum or a platinum alloy (e.g. platinum-rhodium). Finally, the forming body itself is typically also a refractory (e.g. zircon). Not only are the temperatures of the various components of the glass making system at different temperatures (resulting from the gradual cool down of the molten glass as it flows through portions of the platinum components), but portions of the downstream components are formed of different materials than other portions and have different thermal expansion characteristics. For example, the thermal expansion characteristics of the platinum components are different than the thermal expansion characteristics of the forming body. Because the process of forming glass sheet to stringent dimensional requirements, such as for the manufacture of glass sheets for LCD display applications, relies on a stable forming body, the forming body is isolated from the preceding platinum system so that movement of the platinum system does not influence the position of the forming body. An exemplary fusion downdraw apparatus 10 is shown in FIG. 1 comprising melter 12 , finer 14 , stirring vessel 16 , bowl 18 and downcomer 20 . Melter 12 is joined to finer 14 via melter to finer connecting conduit 22 , and finer 14 is joined to stirring vessel 16 via finer to stirring vessel connecting conduit 24 . Batch material 26 is placed in melter 12 and heated to produce a viscous molten glass material 28 . The molten glass flows from stirring vessel 16 to bowl 18 through connecting conduit 30 and from bowl 18 the molten glass flows vertically through feed conduit, or downcomer, 20 . As best seen in FIG. 2 , forming body 32 defines a channel or trough 34 and includes converging forming surfaces 36 a and 36 b . Converging forming surfaces 36 meet at root 38 that forms a substantially horizontal draw line from which molten glass 28 is drawn. Trough 34 is supplied with molten glass 28 from a platinum or platinum alloy inlet pipe 40 that is coupled to forming body 32 . The molten glass overflows the walls of the forming body trough and descends over the outer surfaces of the forming body as separate streams. The separate streams of molten glass flowing over converging forming surfaces 36 a and 36 b meet at root 38 and form glass ribbon 42 . Glass ribbon 42 is drawn from root 38 by opposing edge rollers 44 a and 44 b positioned below the root, and cools as it descends from the root, transitioning from a viscous molten material to an elastic solid. When glass ribbon 42 has reached a final thickness and viscosity in an elastic region of the ribbon, the ribbon is separated across its width in the elastic region to provide an independent glass sheet 46 . As molten glass continues to be supplied to the forming body, and the ribbon lengthens, additional glass sheets are separated from the ribbon. The connection between the downcomer and the forming body occurs at a joint between the downcomer 20 , rigidly connected to the platinum system upstream of the downcomer, and the forming body inlet pipe 40 . To differentiate, the term “platinum system”, as used herein, will be construed to mean the platinum (or platinum alloy) components of the glass making apparatus upstream of inlet pipe 40 , e.g. platinum-containing components 14 , 16 , 18 , 20 , 22 and 24 . To prevent movement of downcomer 20 from influencing the position of forming body 32 , the joint between the downcomer and the forming body inlet pipe is free-floating. That is, downcomer 20 and inlet pipe 40 do not directly touch. Instead, downcomer 20 is inserted a finite distance into the inlet pipe so that a portion 48 of downcomer 20 is positioned within inlet pipe 40 . As best shown in FIG. 3 , the free tip or distal end 50 of downcomer 20 may be positioned above the average level of molten glass within the inlet, at the average level of the molten glass or below the average level of the molten glass. Thus, if movement of the platinum system occurs, downcomer 20 is free to move within inlet pipe 40 without transferring that movement to the inlet pipe and forming body. Similarly, because intentional movement of the forming body is sometimes necessary to balance the mass flow rate of the molten glass over the external forming surfaces of the forming body, a free-floating joint between the downcomer and the inlet allows the inlet to move (in unison with the forming body) without constraint by the downcomer. This decoupling of the downcomer from the inlet pipe provides for independent movement of the downcomer from the inlet pipe. In spite of the advantages of having a free-floating joint between the downcomer and inlet pipe, without a gas-tight seal between these two components the free surface of the molten glass within the inlet would be open to the environment (e.g. the ambient atmosphere), thereby exposing the molten glass to contamination. For example, thermally generated drafts that develop in the downcomer-inlet joint area can lead to temperature gradients in the glass that can in turn result in gaseous inclusions in the glass. A seal between the inlet and downcomer should be capable of meeting multiple objectives. The seal should allow for differential movement of the downcomer from the inlet and forming body, the seal components must withstand elevated temperatures, adjustability between seal components must be maintained, thermal gradients in the molten glass conveying tubes should be minimized, the downcomer should be electrically isolated from the inlet and from ground, visual access should be maintained for alignment purposes, and a gas tight separation between the downcomer, inlet tube assemblies, and the general environment should be established. FIG. 3 depicts an exemplary embodiment of an apparatus 52 for sealing the downcomer-to-inlet joint. The apparatus comprises a bellows 54 , downcomer sealing flange 56 and inlet sealing flange 58 . The apparatus may also comprise one or more downcomer bellows clamps 60 , one or more inlet bellow clamps 62 and electrical insulating material 64 disposed at various positions on or about the sealing apparatus. These and other features that address at least some of the objectives above will be described in more detail below. FIGS. 4 and 5 depict an exemplary sealing flange that may be used as either or both a downcomer sealing flange or an inlet sealing flange. Although downcomer and inlet sealing flanges 56 , 58 may differ in size and shape, their basic materials and construction are generally identical. Consequently, reference will be made to downcomer sealing flange 56 , with the understanding that the description is equally applicable to inlet sealing flange 58 . Downcomer sealing flange 56 may be formed from a single material. However, as illustrated in FIG. 4 , downcomer sealing flange 56 preferably comprises an inner ring 66 formed from platinum or a platinum alloy (e.g. platinum rhodium). Because inner ring 66 is formed from an expensive metal (i.e. a precious metal), the thickness of the inner ring should be thick enough to perform its sealing function while at the same time sufficiently thin to ensure sufficient flexibility to accommodate movement of the vessels (e.g. pipes) to which they are attached. Inner ring 66 may, for example, have a thickness between about 0.0254 cm and 0.0762 cm. Inner ring 66 further defines a cutout 68 in the inner ring interior, and an outer portion 70 . Inner ring 66 may, for example, have an annular shape. Downcomer 20 passes through cutout 68 and is joined to inner ring 66 along inside edge 72 of the ring, such as by welding. Downcomer sealing flange 56 further comprises an outer ring 74 formed from a high temperature-resistant metal, such as a metal comprising chromium, nickel and aluminum. For example, Haynes 214 has been found to be suitable for outer ring 74 . However, other materials can be used, provided they are sufficiently resistant to oxidation at the high temperatures experienced by the outer ring (e.g. greater than about 500° C.) for extended periods of time. Inner ring 66 is joined to outer ring 74 along outer portion 70 of inner ring 66 , such that outer ring 74 is generally concentric to inner ring 66 . Downcomer sealing flange 56 is then joined to downcomer casing 76 enclosing at least a portion of downcomer 20 , such as by bolting through outer ring bolt holes 78 . Downcomer casing 76 may be formed, for example, from steel. Electrical insulating material 64 is positioned between downcomer sealing flange 56 and downcomer casing 76 to provide electrical isolation between the downcomer and the downcomer casing, and between the downcomer sealing flange and electrical ground. For example, RS-100 manufactured by Zircar Refractory Composites, Inc. has been found to be a suitable electrical insulator. However, other electrical insulating materials may be used, provided they exhibit suitable high temperature resistance, and high dielectric constant. Bolts that secure the components (e.g. downcomer sealing flange 56 ) may include, for example, insulating bushings to prevent the connecting bolts from completing an electrical circuit. Insulating material 64 may be placed as necessary to electrically isolate downcomer 20 from downcomer casing 76 , inlet pipe 40 and electrical ground. To accommodate thermal expansion movement between downcomer 20 and downcomer casing 76 , inner ring 66 preferably includes a wave or undulation 80 across a cross section of the inner ring that allows movement of the respective components without undue stress on the flange. The undulation illustrated in FIGS. 3 and 4 is generally in the shape of an ogee. However, different types (shapes) of undulations may be employed. As with downcomer sealing flange 56 , inlet sealing flange 58 preferably comprises an inner ring 82 and an outer ring 84 . Inner ring 82 is preferably formed from a high temperature resistant metal such as platinum or a platinum alloy (e.g. platinum rhodium). Outer ring 84 may be formed from a less expensive heat-resistant metal with low oxidation potential, such as Haynes 214. Inner ring 82 is joined to an outer periphery of inlet pipe 40 , such as by welding, and outer ring 84 is coupled to a portion of an inlet pipe casing, e.g. inlet casing member 86 . Inlet sealing flange 58 is electrically isolated (insulated) from inlet casing member 86 . As illustrated in FIG. 3 , with downcomer sealing flange 56 joined to downcomer 20 and inlet sealing flange 58 joined to inlet pipe 40 , a portion 88 of downcomer 20 extending from the end or mouth 90 of inlet 40 , as well as free surface 92 of molten glass 28 within inlet pipe 40 , would be left exposed to the ambient atmosphere. As described above, sealing apparatus 52 further comprises bellows 54 formed from a material capable of withstanding the high temperatures at the downcomer inlet joint area without significant oxidation or other corrosion. For example, bellows 54 can be formed from stainless steel. A first end of bellows 54 is removably attached to downcomer casing 76 via one or more clamps 60 that bolt to downcomer casing 76 and secure the bellows to the downcomer casing. Similarly, the second, opposite end of bellows 54 is coupled to inlet casing member 86 via one or more clamping members 62 . Clamping members 62 may be secured via bolts, for example. As described supra, these bolts may include, for example, insulating bushings to prevent the connecting bolts from completing an electrical circuit. Bellows 54 is preferably installed such that when the glass making system is in operational readiness (e.g. both ends of bellows 54 clamped to their respective downcomer and inlet casings), bellows 54 is in tension (forcefully expanded or stretched). That is, if the bellows is released at either end (securing clamps removed) in this stretched condition, the bellows preferably will contract longitudinally, allowing for inspection of the interior region of the bellows. Visual access to the interior of the bellows can be used to facilitate radial and/or longitudinal positioning of the downcomer within the inlet pipe. As with downcomer 20 and inlet pipe 40 , additional electrical insulating material 64 is positioned such that bellows 54 is electrically insulated from downcomer casing 76 , inlet casing member 86 and electrical ground. Thus, bellows 54 , downcomer 20 , inlet 40 , downcomer casing member 76 , inlet casing member 86 and electrical ground are all electrically insulated from each other. The positioning of the electrical insulating material 64 will depend of course on the specific design of the sealing apparatus components, and how they are joined. To prevent hydrogen permeation blisters from forming within the molten glass flowing through downcomer portion 88 between downcomer sealing flange 56 and inlet sealing flange 58 , the atmosphere in contact with downcomer portion 88 , represented by reference numeral 89 , may be controlled. Hydrogen permeation blisters occur when the partial pressure of hydrogen in an external environment (such as the atmosphere within the interior region of the bellows) is lower than the partial pressure of hydrogen in the molten glass flowing through a platinum (or platinum alloy) vessel. The high temperature of the molten glass can cause OH radicals within the molten glass to disassociate, and the hydrogen partial pressure difference across the platinum boundary causes the hydrogen to permeate through the boundary, leaving the oxygen to form bubbles in the molten glass. By controlling the partial pressure of hydrogen in bellows interior region 94 , such as by introducing moisture into the bellows region and controlling the dew point, hydrogen permeation blisters can be avoided. For example, water vapor can be introduced into interior region 94 through one or more valves and associated piping (not shown), to adjust the dew point of the atmosphere within the interior region. The dew point of the interior atmosphere can be controlled to prevent the formation of so-called hydrogen permeation blisters. Of course other ways of controlling the hydrogen partial pressure in the bellows interior region 94 can be used, such as introducing hydrogen gas, methane, or other hydrogen sources. However, many hydrogen compounds present an explosion risk, and water vapor has been shown to provide a safe alternative. In certain embodiments, a thermal insulating material (not shown) can be placed within the interior region of the bellows to prevent heat loss through the bellows. For example, a refractory (e.g. ceramic) blanket (not shown) can be placed within the bellows interior. Such refractory, thermally insulating blankets are commercially available. As with most of glass making apparatus 10 , downcomer 20 and inlet pipe 40 are thermally insulated by insulating refractory material. For example, this insulating refractory material may take the form of refractory blocks 96 . In other embodiments the refractory material surrounding the downcomer and inlet pipe may be a castable refractory material. Additionally, downcomer 20 and inlet 40 may be heating members 98 , 100 respectively. Thermocouples 102 and 104 may be used to monitor the temperature of the downcomer and inlet pipe, respectively. A feedback system may be used to link the temperature derived electrical signal from the thermocouples to a temperature regulating controller that regulates the electrical power to the heating members. In some embodiments, an atmosphere within downcomer casing 76 may be controlled in a manner similar to the interior region of bellows 54 . That is, the partial pressure of hydrogen within the casing may be controlled via the introduction of a hydrogen containing constituent, either directly, such as with a hydrogen containing gas, or indirectly, via water vapor, as indicated by arrows 106 . In addition, inlet pipe 40 , and refractory blocks 96 surrounding the inlet pipe, may be surrounded by a second, inlet casing 108 . Because refractory blocks 96 are typically porous, a third atmosphere within enclosure 108 , represented by reference numeral may be controlled similar to the first and second atmospheres in the downcomer region and within the region surrounded by bellows 54 . Thus, a partial pressure of hydrogen in the third atmosphere may be controlled independently from the first and second atmospheres 89 and 94 . It should be emphasized that the above-described embodiments of the present invention, particularly any “preferred” embodiments, are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiments of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and protected by the following claims.
A sealing apparatus for use in conveying molten glass from a first vessel to a second vessel, wherein at least a portion of the first vessel is nested within the second vessel without contact between the first and second vessels, and a flexible member comprising a gas-tight seal separates an atmosphere enclosed by the sealing apparatus and an ambient atmosphere. The sealing apparatus is useful for flexibly sealing a non-contact joint between conduits for supplying molten glass to a forming body.
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BACKGROUND OF THE INVENTION This invention relates to purified natural glass products having low concentrations of soluble substances. More particularly, this invention relates to purified natural glass products having low slurry electrical conductivities (i.e., less than about 18 μS-cm -1 ). Preferred embodiments are further characterized by low concentrations of soluble iron (i.e., less than about 2 mg Fe/kg product) and/or low concentrations of soluble aluminum (i.e., less than about 10 mg Al/kg product). These products may be prepared from natural glasses and natural glass products, including, for example, expanded perlite, pumice, expanded pumice, and volcanic ash. The products of the present invention retain the intricate and porous characteristics of the feed material but possess low concentrations of soluble substances, thereby permitting much greater utility, particularly in filtration applications. DESCRIPTION OF THE RELATED ART Throughout this application, various publications, patents, and published patent applications are referred to by an identifying citation; full citations for these documents may be found at the end of the specification. The disclosure of the publications, patents, and published patent specifications referenced in this application are hereby incorporated by reference into the present disclosure to more fully describe the state of the art to which this invention pertains. Many methods for the separation of particles from fluids employ porous siliceous media materials, such as diatomite, perlite, and pumice, as filter aids. The intricate porous structure unique to these siliceous materials is particularly effective for the physical entrapment of particles in filtration processes. The present invention relates to purified products derived from natural glasses and natural glass products which have particular utility in filtration applications and are hereinafter referred to as "purified natural glass products" or "purified natural glass filter aid products". The term "natural glass" is used herein in the conventional sense and refers to natural glasses, commonly referred to as volcanic glasses, which are formed by the rapid cooling of siliceous magma or lava. Several types of natural glasses are known, including, for example, obsidian, pitchstone, perlite, and pumice. Obsidian is generally dark in color with a vitreous luster and a characteristic conchoidal fracture. Pitchstone has a waxy resinous luster and is frequently brown, green, or gray. Perlite is generally gray to green in color with abundant spherical cracks which cause it to break into small pearl-like masses. Pumice is a very lightweight glassy vesicular rock. Volcanic glasses such as perlite and pumice occur in massive deposits and find wide commercial use. Volcanic ash, often referred to as tuff when in consolidated form, consists of small particles or fragments which are often in glassy form; as used herein, the term natural glass encompasses volcanic ash. Most natural glasses are chemically equivalent to rhyolite. Natural glasses which are chemically equivalent to trachyte, dacite, andesite, latite, and basalt are known but are less common. The term obsidian is generally applied to massive natural glasses that are rich in silica (i.e., SiO 2 ). Obsidian glasses may be classified into subcategories according to their silica content, with rhyolitic obsidians (containing typically about 73% SiO 2 by weight) as the most common (Berry et al., 1983). Perlite is a hydrated natural glass containing typically about 72-75% SiO 2 , 12-14% Al 2 O 3 , 0.5-2% Fe 2 O 3 , 3-5% Na 2 O, 4-5% K 2 O, 0.4-1.5% CaO (by weight), and small concentrations other metallic elements. Perlite is distinguished from other natural glasses by a higher content (2-5% by weight) of chemically bonded water, the presence of a vitreous, pearly luster, and characteristic concentric or arcurate onion skin-like (i.e., perlitic) fractures. Perlite products are often prepared by milling and thermal expansion, and possess unique physical properties such as high porosity, low bulk density, and chemical inertness. Depending on their quality and processing, perlite products are used as filter aids, lightweight insulating materials, filler materials, and chemical carriers. Expanded perlite has been used in filtration applications since about the late 1940's (Breese and Barker, 1994). Expanded perlite is also used as an absorbent for treating oil spills (e.g., Stowe, 1991). Conventional processing of perlite consists of comminution (crushing and grinding), air size classification, thermal expansion, and air size classification of the expanded material to meet the specification of the finished product. For example, perlite ore is crushed, ground, and classified to a predetermined particle size range (e.g., passing 30 mesh), then the classified material is heated in air at a temperature of 870-1100° C. in an expansion furnace, where the simultaneous softening of the glass and vaporization of contained water leads to rapid expansion of glass particles to form a frothy glass material with a bulk volume up to 20 times that of the unexpanded ore. The expanded perlite is then air classified to meet the size specification of the final product. The expanded perlite product may further be milled and classified for use as filter aid or filler material (Breese and Barker, 1994). The presence of chemically bonded water in other natural glasses (for example, pumice and volcanic ash) often permits "thermal expansion" in a manner analogous to that commonly used for perlite. Pumice is a natural glass characterized by mesoporous structure (e.g., having pores or vesicles with a size up to about 1 mm). The highly porous nature of pumice gives it a very low apparent density, in many cases allowing it to float on the surface of water. Most commercial pumice contains from about 60 to about 70% SiO 2 by weight. Pumice is typically processed by milling and classification (as described above for perlite), and products are primarily used as lightweight aggregates and also as abrasives, absorbents, and fillers. Unexpanded pumice and thermally expanded pumice (prepared in a manner analogous to that used for perlite) may also be used as filter aids in some cases (Geitgey, 1994). Natural glass products, including, for example, expanded perlite, pumice, and expanded pumice have found widespread utility in filtration applications. The term "filtration" is used herein in the conventional sense and refers to the removal of particulate matter from a fluid in which the particulate matter is suspended. A common filtration process is one which comprises the step of passing the fluid through a filter aid material supported on a septum (e.g., mesh screen, membrane, or pad). The working principles of filtration using porous media have been developed over many years (Carman, 1937; Heertjes, 1949, 1966; Ruth, 1946; Sperry, 1916; Tiller, 1953, 1962, 1964), and have been recently reviewed in detail from both practical perspectives (Cain, 1984; Kiefer, 1991) as well as from their underlying theoretical principles (Bear, 1988; Norden, 1994). The intricate porous structure of many natural glass products, including, for example, expanded perlite, pumice, and expanded pumice, is particularly effective for the physical entrapment of particles in filtration processes. For example, natural glass products are often applied to a septum to improve clarity and increase flow rate in filtration processes, in a step sometimes referred to as "precoating." Natural glass products are also often added directly to a fluid as it is being filtered to reduce the loading of undesirable particulate at the septum while maintaining a designed liquid flow rate, in a step often referred to as "body feeding." Depending on particular separation involved, natural glass products may be used in precoating, body feeding, or both. In some filtration applications, different natural glass products (e.g., different grades and/or different natural glass products) are blended together to further modify or optimize the filtration process. Also, natural glass products are sometimes combined with other substances. In some cases, these combinations may involve simple mixtures, for example, with other filter aid components, including, for example, diatomite, cellulose, activated charcoal, clay, or other materials. In other cases, these combinations are composites in which natural glass products are intimately compounded with other ingredients to make sheets, pads, or cartridges. Still more elaborate modifications of any of these natural glass products are used for filtration or separation, involving, for example, surface treatment and the addition of chemicals to natural glass products, mixtures, or their composites. In certain circumstances, perlite products, especially those which are surface treated, may also exhibit unique properties during filtration that can greatly enhance clarification or purification of a fluid (Ostreicher, 1986). The intricate and porous structure of many natural glass products, including, for example, expanded perlite, pumice, and expanded pumice, also provides them with unique filler properties. For example, expanded perlite products are often used as insulating fillers, resin fillers, and in the manufacture of textured coatings. Many natural glass products, such as perlite and pumice products, are aluminosilicates and are therefore essentially chemically inert in most environments. As naturally occurring glasses, they also contain various impurities such as mineral grains, fluid inclusions, and surface contaminants. When placed in contact with a fluid phase (for example, when used as a filter aid or as a filler), soluble substances may be released from the natural glass product into the filtrates or the filled products, greatly diminishing the quality of the fluid. These soluble substances may be detrimental to the quality of the products where contamination needs to be carefully controlled. As ingredients in polymers, plastics, paints, coatings, and other formulations, natural glass products, such as perlite and pumice products, also come into contact with most of the other ingredients in the formulation. For this reason, natural glass products with high purity, surface cleanliness and low chemical reactivity are often desirable. As used herein, the term "soluble substances" relates to components of a natural glass product which (i) are dissolved in a fluid when the natural glass product is placed in contact with that fluid; and which (ii) contribute to the resulting electrical conductivity of the fluid. Soluble substances of particular interest are those containing iron (i.e., Fe) and/or aluminum (i.e., Al) which yield dissolved iron ions (e.g., Fe +2 , Fe +3 ) and dissolved aluminum ions (e.g., Al +3 ). Fluids of particular interest are those containing water. Soluble substances of particular interest are those which are soluble in water or other aqueous media. Results of tests for the concentrations of soluble substances of commercially available expanded perlite products from worldwide sources (using the standard methods described below) are shown below in Table I. The lowest value of beer soluble iron (BSI) was found to be 3 mg Fe/kg product and the lowest value of beer soluble aluminum (BSAl) was found to be 11 mg Al/kg product. TABLE I______________________________________Samples BSI BSA1 ConductivityBrand Grade Origin mg/kg mg/kg μS/cm______________________________________HARBORLITE 2000 US 4 16 33.8HARBORLITE 200 US 4 52 90.9HARBORLITE J250S England 4 31 31.8HARBORLITE PF England 11 25 54.4HARBORLITE J208 France 13 47 42.2HARBORLITE 130/21S France 9 267 86.6PERFILTRA 443 Brazil 3 179 35.0PERFILTRA 807 Brazil 3 39 58.7DICALITE 447 Mexico 13 51 88.9DICALITE 4147 Mexico 12 43 40.0DICALITE 4408 Europe 4 19 38.5NORDISK NP#30 Norway 5 17 20.5WINKELMANN W12 Europe 14 11 75.1WINKELMANN W28 Europe 8 18 22.5CECA FLO4 Europe 9 20 31.5CECA FLOR Europe 6 15 38.0SEITZ Perlite A Europe 17 17 34.2______________________________________ A method of leaching ground (unexpanded) perlite with a solution of an inorganic acid prior to thermal expansion has been described (Houston, 1959). By this method, the expansion characteristics of perlite ore, and a filter aid prepared from the resulting expanded perlite, was found to have modified flow rate characteristics and improved light reflecting properties. The reference, however, does not pertain to the reduction of the concentration of soluble substances. In contrast, the purified natural glass products and purified natural glass filter aid products of the present invention are purified so as to reduce the concentrations of soluble substances. A method of using tannic acid (also known as gallotannic acid or tannin, with a typical chemical formula of C 76 H 52 O 46 ) or gallic acid (also known as 3,4,5-trihydroxybenzoic acid, C 7 H 6 O 5 ) to produce a low beverage soluble iron content filter aid has been disclosed (Bradley and McAdam, 1979). In this method, tannic or gallic acid is first mixed with the filter aid and, subsequently, the treated material is either thermally dried directly, or filtered and rinsed with purified water to remove excess acid and then thermally dried. The lower concentration of beverage soluble iron in the resulting product is achieved by surface fixation of the metal by the complexing acid; that is, the metal remains in the product, but in complexed, and therefore insoluble, form. In practice, however, the presence of residual acid (which is essential to this fixation method) is undesirable in many applications. In contrast, the purified natural glass products and purified natural glass filter aid products of the present invention have low concentrations of soluble substances (including, but often not merely, beverage soluble iron), and are also free of acid residues. A method for preparing a preservative for green fodder which involves mixing expanded perlite with an acid has been presented (Jung, 1963). Also, a method of preparing purifying agents consisting of activated siliceous porous mineral substances has also been described (Morisaki and Watanabe, 1976); in this method, siliceous material, such as expanded perlite, is mixed and baked with hydrochloric and/or sulfuric acid, and resulting solubilized metals in the siliceous material act as coagulants or coagulation sites for fine particles for waste water treatment. In both methods, the acid remains with the treated materials. Furthermore, the references do not contemplate applications for the resulting treated materials which require low concentrations of soluble substances. The purified natural glass products and purified natural glass filter aid products of the present invention retain the intricate porous structure unique to these natural glasses, such as expanded perlite or pumice, but have very low concentrations of soluble substances, thereby permitting much greater utility, particularly as filter aids or fillers for products for which contamination by the soluble substances must be carefully controlled. SUMMARY OF THE INVENTION One aspect of the present invention pertains to purified natural glass products having a low concentration of soluble substances as defined by a slurry electrical conductivity of less than about 18 μS-cm -1 , preferably less than about 15 μS-cm -1 , more preferably less than about 10 μS-cm -1 , yet more preferably less than about 8 μS-cm -1 . In a preferred embodiment, the purified natural glass product is further characterized by a beer soluble iron content of less than about 2 mg Fe/kg product, more preferably equal to or less than about 1 mg Fe/kg product. In another preferred embodiment, the purified natural glass product is further characterized by a beer soluble aluminum content of less than about 10 mg Al/kg product, more preferably less than 8 mg Al/kg product, still more preferably less than about 5 mg Al/kg product, yet more preferably less than about 1 mg Al/kg product. In still another preferred embodiment, the purified natural glass product is further characterized by a beer soluble iron content of less than about 2 mg Fe/kg product and a beer soluble aluminum content of less than about 10 mg Al/kg product. In a preferred embodiment, the purified natural glass product is derived from expanded perlite, pumice, expanded pumice, or volcanic ash. Another aspect of the present invention pertains to filter aid compositions (i.e., filter composite media) comprising a purified natural glass product as described herein. In a preferred embodiment, the filter composite medium is in the form of a mixture (i.e., with one or more other filter aid components, including, for example, diatomite, cellulose, activated charcoal, and clay). In another preferred embodiment, the filter composite medium is in the form of a sheet, a pad, or a cartridge. Still another aspect of the present invention pertains to methods of filtration comprising the step of passing a fluid containing suspended particulates through a filter aid material supported on a septum, wherein said filter aid material is a purified natural glass product as described herein. In a preferred embodiment, the method of filtration involves filtration of a fluid and/or fluid suspension comprising water, beverage, a botanical extract, an animal extract, a fermentation broth, blood or blood products, a vaccine, or a chemical. DESCRIPTION OF THE PREFERRED EMBODIMENTS A. Methods for Preparing the Purified Natural Glass Products and Purified Natural Glass Filter Aid Products of the Invention As described above, the purified natural glass products and purified natural glass filter aid products of the present invention have low concentrations of soluble substances and retain the intricate and porous characteristics of the feed material. Any known method for preparing the purified natural glass products and purified natural glass filter aid products of the present invention may be used. One preferred method of preparing the products of the present invention is by controlled acid leaching. This method effects cleaning of the feed material's surface and removes soluble substances from the natural glass, resulting in the desirable low concentrations of soluble substances. Feed material, such as commercially available feed materials, may be used. For example, for preparation of perlite products, HARBORLITE 2000 (from Harborlite Corporation, Vicksburg, Mich.) is a useful feed material. Gravity separation, for example, hydrocyclone separation, may be used to further upgrade the feed material to remove less porous particles (for example, unexpanded perlite) and mineral impurities. The feed material may be leached, for example, by strirring in a slurry of feed material and an acid solution. The acid solution may comprise inorganic or organic acids, for example, sulfuric acid (i.e., H 2 SO 4 ), hydrochloric acid (i.e., HCl), nitric acid (i.e., HNO 3 ), phosphoric acid (i.e., H 3 PO 4 ), acetic acid (i.e., CH 3 COOH) or citric acid (i.e., C 6 H 3 O 7 .H 2 O), or combinations the Natural glass has a much higher solubility in hydrofluoric acid (i.e., HF) and ammonium bifluoride (i.e., NH 4 F.HF). Leaching by these latter chemicals can result in a loss of the intricate porous structure of the natural glass, and should therefore be used only under strictly controlled conditions to provide slight surface etching. Leaching may be conducted at either ambient conditions (e.g., room temperature, atmospheric pressure) or with heating and/or under pressurized conditions. Parameters such as solids content (i.e., the weight ratio of solid to liquid), acid concentrations, and leaching conditions, such as temperature, pressure, and leaching time, may be optimized on the basis of the properties of the feed material and the acid selected to achieve the desired level of solubility in the final product. Examples of typical parameters include: solids content of from about 1:5 to about 1:100; acid concentrations of from about 0.01 moles/liter to about 15 moles/liter (i.e., "concentrated"); leaching temperatures of from about room temperature (i.e., 20° C.) to about 250° C., more usually about 100° C.; leaching pressures of from about 0.1 atmosphere to about 20 atmospheres, more usually about 1 atmosphere; and leaching time of from about 10 min to about 10 hours, more usually about 1-2 hours. The leached material is dewatered, for example, by filtration, to remove the spent acid and the solubilized substances, and subsequently rinsed with purified (e.g., distilled, deionized, or equivalent quality) water. The electrical conductivity of the filtrates and washes is carefully monitored to ensure a thorough rinse. Rinsing with a solution of a chelating agent such as citric acid or ammonium citrate and redispersion of the filter cake in purified water may be used to further reduce the level of solubilities. The dewatered and rinsed material is then thermally dried, for example, in air at about 110° C. to approximately constant weight. B. Methods for Characterizing the Purified Natural Glass Products and Purified Natural Glass Filter Aid Products of the Invention 1. Slurry Electrical Conductivity Pure water is a very poor conductor of electricity. The electrical conductivity of water is increased by the presence of dissolved electrolytes (e.g., cations and anions). The electrical conductivity of a slurry of a solid powder in purified water, hereinafter referred to as the slurry electrical conductivity, provides a means of evaluating the total concentration of water soluble electrolytes in the solid material. The greater the conductivity of the slurry, the greater the concentration of water soluble electrolytes (i.e., soluble substances) in the solid powder. In the present disclosure, the slurry electrical conductivity was determined using a conductivity cell by measuring the conductivity of the supernatant of a 10% (w/v) slurry made from a powder product and deionized water. The sample material is dried to constant weight at 110° C. in air, and subsequently allowed to cool to room temperature in air (i.e., dried). A 10 g sample is added to a 250 mL beaker containing 100 mL of distilled or deionized water with a maximum electrical conductivity of less than 1 microsiemens per centimeter (<1 μS-cm -1 ). The mixture is swirled for 15 sec to fully suspend the slurry, then allowed to settle. The mixture is swirled again after 15 min, and allowed to settle for not less than 1 hr. The supernatant is decanted into a cell tube, and a conductivity cell (Cole-Parmer Instrument Co. Electric Conductivity Meter, Model 1481-61, with a 500 series cell ) dipped into the liquid. The cell is moved up and down several times to release any air bubbles trapped in the cell, and the resistivity measured using the conductivity bridge contained within the meter. The conductivity cell is calibrated (to obtain a cell calibration constant) with solutions of known electrical conductivity. The purified natural glass products and purified natural glass filter aid products of the present invention have an electrical conductivity of less than 18 μS-cm -1 (usually in the range of from about 0.5 to about 18 μS-cm -1 ), preferably less than 15 μS-cm -1 (usually in the range of from about 0.5 to about 15 μS-cm -1 ), more preferably less than 10 μS-cm -1 (usually in the range of from about 0.5 to about 10 μS-cm -1 ), yet more preferably less than 8 μS-cm -1 (usually in the range of from about 0.5 to about 8 μS-cm -1 ). Compared with the electrical conductivities of conventional perlite filter aids, which are typically greater than 20 μS-cm -1 (as shown in Table I), this represents a significant reduction in concentration of soluble substances in the purified natural glass products of the present invention. 2. Beer Soluble Iron (BSI) and Beer Soluble Aluminum (BSAl) Large volumes of perlite and other filter aid products are used to filter beverages and fermentation broths. Beer is a convenient and well characterized example of such an application. Contamination of the filtered liquids with metals such as iron (i.e., Fe, as the ions Fe 2+ and/or Fe 3+ ) or aluminum (i.e., Al, as the ion Al 3+ ) is often of concern. A reliable analytical method has been established in the brewing industry to determine the solubility of iron from filter aid products in beer (beer soluble iron, or BSI) (American Society of Brewing Chemists, 1987). The preferred analytical method used in the present invention involves extraction with decarbonated beer and determination of extracted iron concentration in the beer filtrate using a colorimetric method. The sample is dried to constant weight at 110° C. in air, and subsequently allowed to cool to room temperature in air (i.e., dried). A 5 g sample is added to 200 mL of decarbonated beer (in this case, BUDWEISER, registered trademark of Anheuser-Busch) at room temperature, and the mixture swirled intermittently for an elapsed time of 5 min and 50 sec. The mixture is then immediately transferred to a funnel containing 25 cm diameter filter paper, from which the filtrate collected during the first 30 sec is discarded. Filtrate is collected for the next 150 sec, and a 25 mL portion is treated with approximately 25 mg of ascorbic acid (i.e., C 6 H 8 O 6 ), to reduce dissolved iron ions to the ferrous (i.e., Fe 2+ ) state (thus yielding "sample extract"). The color is developed by addition of 1 mL of 0.3% (w/v) 1,10-phenanthroline (i.e., o-phenanthroline, C 12 H 8 N 2 ), and, after 30 min, the absorbance of the resulting sample solution is compared to a standard calibration curve. The calibration curve is prepared from standard iron solutions of known concentration in beer. Untreated filtrate is used as a method blank to correct for turbidity and color. Absorbance is measured at 505 nm using a spectrophotometer, in this case, a Milton & Bradley Spectronic. The quantitation limit of this method is approximately 1 mg Fe/kg product. The preferred method for determining the solubility of aluminum from filter aid products in beer (beer soluble aluminum, or BSAl) in this invention uses graphite furnace atomic absorption spectrophotometry (GFAAS). Sample extracts are prepared according to the American Society of Brewing Chemists method for beer soluble iron (as described above), and centrifuged to removed suspended fine particles. Beer samples with aluminum concentration exceeding the optimum range of analysis are appropriately diluted. Aluminum concentration in the samples is corrected by the amount of aluminum present in the same beer used for extraction in order to calculate the amount of aluminum dissolved from the solids. The method has a quantitation limit of 0.2 mg Al/kg product. The purified natural glass products and purified natural glass filter aid products of the present invention have a beer soluble iron (BSI) content of less than about 2 mg Fe/kg product (usually in the range of from about the quantitation limit to about 2 mg Fe/kg product) and a beer soluble aluminum (BSAl) content of less than about 10 mg Al/kg product (usually in the range of from about 0.5 to about 10 mg Al/kg product); preferably a beer soluble iron (BSI) content of less than about 2 mg Fe/kg product (usually in the range of from about the quantitation limit to about 2 mg Fe/kg product) and a beer soluble aluminum (BSAl) content of less than about 8 mg Al/kg product (usually in the range of from about 0.5 to about 8 mg Al/kg product); more preferably a beer soluble iron (BSI) content of less than about 2 mg Fe/kg product (usually in the range of from about the quantitation limit to about 2 mg Fe/kg product) and a beer soluble aluminum (BSAl) content of less than about 5 mg Al/kg product (usually in the range of from about 0.5 to about 5 mg Al/kg product); still more preferably a beer soluble iron (BSI) content of equal to or less than about 1 mg Fe/kg product (usually at or below the quantitation limit) and a beer soluble aluminum (BSAl) content of less than about 1 mg Al/kg product (usually in the range of from about 0.5 to about 1 mg Al/kg product). Compared with the beer soluble iron and beer soluble aluminum contents of conventional perlite filter aids, which are typically greater than 3 mg Fe/kg product and greater than 10 mg Al/kg product, these represent a significant reduction in the concentrations of beer soluble iron and/or beer soluble aluminum in the purified natural glass products of the present invention. C. Methods of Using the Purified Natural Glass Products and Purified Natural Glass Filter Aid Products of the Invention The purified natural glass products of the present invention can be used in a manner analogous to the currently available natural glass products, including, for example, as a filter aid and as a filler. The intricate porous structure unique to these natural glass materials is particularly effective for the physical entrapment of particles in filtration processes. Furthermore, the very low concentrations of soluble substances of these products permit greater utility in the filtration of the fluids for which the soluble substances from filter aid must be carefully controlled. The purified natural glass products of the present invention can be applied to a septum (i.e., used in precoating) to improve clarity and increase flow rate in filtration processes. They can also be added directly to a fluid as it is being filtered to reduce the loading of undesirable particulates at the septum while maintaining a designed liquid flow rate (i.e., used in "body feeding"). In some filtration applications, the purified natural glass products of the present invention can be used as mixtures with other filter aids or as composites (i.e., as composite filter media) in which they are intimately compounded with other ingredients to make sheets, pads, or cartridges. The purified natural glass product of the present invention can also be used as the base material for more elaborate modifications, involving, for example, surface treatment. In certain circumstances, purified natural glass products, especially those which are surface treated, may also exhibit unique properties during filtration which can greatly enhance clarification or purification of a fluid or achieve selective removal of undesired substances. The purified natural glass products of the present invention may be used as a filter aid in filtration; that is, for the removal of particulate matter from a fluid in which the particulate matter is suspended, in a method comprising the step of passing the fluid containing suspended particulates through a purified natural glass products of the present invention (i.e., as a filter aid material) supported on a septum. Examples of fluids and/or fluid suspensions which may be filtered using the purified natural glass products of the present invention include: water, beverages (for example, beer, fruit juice), botanical extracts (for example, sugar solutions, vegetable oils, flavors, antibiotics), animal extracts (for example, fats, oils), fermentation broths (for example, cell suspensions and cell cultures, including, for example, yeast extracts, bacterial broths), blood and blood products (for example, whole blood, blood plasma, serum albumin, immunoglobulins), vaccines (for example, pertussis vaccine), and chemicals (for example, organic and inorganic chemicals including, for example, solvents such as methanol, and solutions such as aqueous sodium hypophosphite). D. Examples Purified natural glass products of the present invention and methods for their preparation are described in the following examples, which are offered by way of illustration and not by way of limitation. Commercially available expanded perlite products, HARBORLITE 2000 and HARBORLITE 200 (from Harborlite Corporation, Vicksburg, Mich.) were used as feed materials. The HARBORLITE 2000 had a particle size distribution (PSD) as determined by a laser diffraction method between 20 μm (d 10 ) and 108 μm (d 90 ), and the HARBORLITE 200 had a PSD between 5.5 μm (d 10 ) and 43 μm (d 90 ). Two batches of each of the two feed materials were leached in a 0.5N sulfuric acid (i.e., H 2 SO 4 ) solution with a solids content (i.e., weight ratio of solid to liquid) of 1:20 (for batch 1) and 1:10 (for batch 2), at the temperature of boiling for 60 minutes. The leached products were filtered in a 15 cm Buchner filter and the filter cakes were rinsed with deionized water until the filtrates showed a conductivity less than 3 μS-cm -1 . The quantity of rinse water used was about 5 times the volume of the acid solution used in leaching. The cakes were then dried in air in an oven overnight at 120° C. Tests to determine the concentration of soluble substances were carried out according to the methods described above. The results for both the purified products of the present invention and the feed materials are compared in Table II. The products of this example had electrical conductivities of less than 7 μS-cm -1 , beer soluble iron contents of less than 2 mg Fe/kg product, and beer soluble aluminum contents of less than 5 mg Al/kg. Particle size distributions of the products were determined to be essentially identical to those of the feed materials. TABLE II______________________________________ BSI BSA1 ConductivityProduct mg/kg mg/kg μS/cm______________________________________Conventional Harborlite 2000 (US) 4 16 33.8Equivalent purified glass product - <1 0.8 not det'dBatch 1Equivalent purified glass product - <1 2.0 6.2Batch 2Conventional Harborlite 200 (US) 4 52 90.9Equivalent purified glass product - <1 0.8 not det'dBatch 1Equivalent purified glass product - 1 4.0 6.5Batch 2______________________________________ E. References The disclosures of the publications, patents, and published patent specifications referenced below are hereby incorporated by reference into the present disclosure to more fully describe the state of the art to which this invention pertains. American Society of Brewing Chemists (1987), Methods of Analysis of the American Society of Brewing Chemists. Bradley, T. G. and McAdam, R. L. (1979), U.S. Pat. No. 4,134,857. Bear, J. (1988), Dynamics of Fluids in Porous Media (New York: Dover Publications, Inc.), pp. 161-176. Berry, L. G. et al. (1983), Mineralogy (Second edition) (New York: Freeman and Co.); pp. 540-542. Breese, R. O. Y. and Barker, J. M. (1994), In Industrial Minerals and Rocks (Littleton, Colo.: Society for Mining, Metallurgy, and Exploration, Inc.), pp. 735-749. Cain, C. W. Jr. (1984), In Encyclopedia of Chemical Processing and Design (New York: Marcel Dekker), pp. 348-372. Carman, P. (1937), Trans. Institution of Chem. Eng., pp. 150-166. Geitgey, R. P. (1979), In Industrial Minerals and Rocks (Littleton, Colo.: Society for Mining, Metallurgy, and Exploration, Inc.), pp. 803-813. Heertjes, P. et al. (1949), Recueil, Vol. 68, pp. 361-383. Heertjes, P. et al. (1966), in Solid-Liquid Separation (London: Her Majesty's Stationery Office), pp. 37-43. Houston, H. H. (1959), U.S. Pat. No. 2,898,303. Jung, J. (1965), Belgium Patent 657,019. Kiefer, J., (1991), Brauwelt International, IV/1991, pp. 300-309. Morisaki, K. and Watanabe, M. (1976), U.S. Pat. No. 3,944,687. Norden, H., et al. (1994), Separation Science and Technology, Vol. 29(10), pp. 1319-1334. Ostreicher, E. A. (1986), U.S. Pat. No. 4,617,128. Ruth, B. (1946), Industrial and Engineering Chemistry, Vol. 38(6), pp. 564-571. Sperry, D. (1916), Metallurgical and Chemical Eng., Vol. XV(4), pp. 198-203. Stowe, G. B. (1991), U.S. Pat. No. 5,035,804. Tiller, F., et al. (1953), Chemical Engineering Progress, Vol. 49(9), pp. 467-479. Tiller, F., et al. (1962), A.I.Ch.E. Journal, Vol. 8(4), pp. 445-449. Tiller, F., et al. (1964), A.I.Ch.E. Journal, Vol. 10(1), pp. 61-67.
This invention relates to purified natural glass products having low concentrations of soluble substances. More particularly, this invention relates to purified natural glass products having low slurry electrical conductivities (i.e., less than about 18 μS-cm -1 ). Preferred embodiments are further characterized by low concentrations of soluble iron (i.e., less than about 2 mg Fe/kg product) and/or low concentrations of soluble aluminum (i.e., less than about 10 mg Al/kg product). These products may be prepared from natural glasses and natural glass products, including, for example, expanded perlite, pumice, expanded pumice, and volcanic ash. The products of the present invention retain the intricate and porous characteristics of the feed material but possess low concentrations of soluble substances, thereby permitting much greater utility, particularly in filtration applications.
2
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile phone with a hidden input device, more particularly, to a mobile phone with a rotatably hidden alphabetical keyboard. 2. Description of the Related Art FIG. 1 (Prior Art) is a schematic structural diagram of a mobile phone. Generally, the mobile phone ( 100 ) comprises a main body ( 110 ) with a keyboard ( 120 ). The keyboard ( 120 ) represents a standard telephone keyboard. In FIG. 1 , the keyboard ( 120 ) includes ten number keys and two function keys such as “1”, “2”, “3”, “4”, “5”, “6”, “7”, “8”, “9”, “0”, “*”, and “#”. Moreover, the mobile phone ( 100 ) in prior art also has functions to enter alphabetical characters, Chinese characters, or specific functional options through dedicated software. In FIG. 1 , a user can enter alphabetical characters by the twelve keys of the keyboard ( 120 ). For example, pressing “3” once generates an alphabetical character, “D”, and pressing “3” twice, generates an alphabetical character, “E”. Thus, users can enter different characters or functional options by the standard telephone keyboard while maintaining space and weight considerations for the mobile phone ( 100 ). When entering a long alphabetical string by the keyboard ( 120 ) of the conventional mobile phone ( 100 ), however, it is inconvenient and confusing when pressing the same key several times to choose different characters. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a mobile phone with small size and a dedicated keyboard, designed to easily input different alphabetical characters. The present invention provides a mobile phone with a hidden input device, comprising a main body and an input device. The input device is coupled to the main body to input data and rotatably connected to the main body between a first position and a second position by a rotating device, wherein the input device has a visible portion with a plurality of first input elements covered by the main body when the input device is fixed in the first position, and a hidden portion with a plurality of second input elements appearing when the input device is fixed in the second position. The first input elements of the mobile phone of the invention comprise a plurality of keys, and the second input elements comprise a plurality of keys or a touch pad. Moreover, the first input elements are used to enter numbers when the input device is fixed in the first position, and the first elements and the second elements input alphabetical characters and a plurality of specific functional options. The input device of the mobile phone mentioned above also comprises a flexible printed circuit board (FPCB) to transmit the signal from the input device to the main body. The main body also comprises a first node and a second node, wherein the first node conducts the flexible printed circuit board of the input device in the first position to receive the signal from the input device in the first position, and the second node conducts the flexible printed circuit board of the input device in the second position to receive the signal from the input device in the second position. A user generally dials a phone number only by the number keys on the mobile phone of present invention when the input device is fixed in the first position, and can enter alphabetical characters or functional options when the input device is rotated and fixed in the second position. Therefore, the mobile phone of the present invention is easily carried when the input device is fixed in the first position, and is more convenient to enter alphabetical characters than the mobile phone of the prior art when the input device is expanded and fixed in the second position like a standard keyboard. The mobile phone with a hidden input device of the present invention can exchange the positions of keys with specific functions on the visible portion or the hidden portion through dedicated software according to the utility rate. BRIEF DESCRIPTION OF THE DRAWINGS These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description, appended claims and accompanying diagrams where: FIG. 1 (Prior Art) is a schematic structural diagram of a mobile phone; FIG. 2 is a three-dimensional diagram of the mobile phone of the first embodiment; FIG. 3 a is a front view of the input keyboard in the first position of the first embodiment; FIG. 3 b is a lateral view of the input keyboard in the first position of the first embodiment; FIG. 4 is a front view of the input keyboard in the second position of the first embodiment; FIG. 5 is a three-dimensional diagram of the mobile phone of the second embodiment; FIG. 6 is a lateral view of the mobile phone of the second embodiment; FIG. 7 is a partial section view of the input keyboard in the first position of the third embodiment; and FIG. 8 is a partial section view of the input keyboard in the second position of the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 2 to FIG. 4 , the first embodiment of the present invention is a mobile phone ( 1 ) with a hidden input device ( 20 ). The mobile phone ( 1 ) comprises a main body ( 10 ) and an input device ( 20 ), which is similar to the keyboard in the prior art. A rotating device such as a shaft ( 50 ) in FIG. 2 fixes the input device ( 20 ) to the main body ( 10 ) so that the input device ( 20 ) rotates relative to the main body ( 10 ). The input device ( 20 ) has a visible portion ( 30 ) and a hidden portion ( 40 ). FIG. 2 only shows the visible portion ( 30 ) when the input device ( 20 ) is fixed in the first position. According to the front view in FIG. 3 a and the lateral view in FIG. 3 b , the main body ( 10 ) totally covers the hidden portion ( 40 ) so that a user only uses the visible portion ( 30 ), which is similar to the keyboard in the prior art, of the input device ( 20 ) to input data. In FIG. 2 and FIG. 3 a , the visible portion ( 30 ) has a plurality of first input elements, or a plurality of keys ( 32 ). The keys ( 32 ) are designed similarly to the keyboard ( 120 ) of the usual mobile phone ( 100 ) in FIG. 1 and include ten number keys and two function keys such as “1”, “2”, “3”, “4”, “5”, “6”, “7”, “8”, “9”, “0”, “*”, and “#” to input data. Thus, the functions of the input device ( 20 ) in the first position are the same as the mobile phone ( 100 ) in FIG. 2 . To enter symbols such as alphabetical characters or other functional options such as switching case, users rotate the input device ( 20 ) relative to the main body ( 10 ) to the second position. For example, users rotate the input device ( 20 ) 90 degrees clockwise to the second position. The second position of the input device ( 20 ) is accordingly perpendicular to the first position of the input device ( 20 ). In FIG. 4 , the main body ( 10 ) does not cover the hidden portion ( 40 ) so that the whole input device ( 20 ) can be used. In FIG. 4 , when the input device ( 20 ) is fixed in the second position, the visible portion ( 30 ) and the hidden portion ( 40 ) form a complete alphabetical keyboard. The hidden portion ( 40 ) has a plurality of second input elements such as a plurality of keys ( 42 ) and a touch pad ( 44 ) to input alphabetical characters. The keys ( 32 ) of the first input elements set on the visible portion ( 30 ) are also used to input alphabetical characters. In FIG. 4 , the key, which is used to input “1” when the input device is fixed in the first position, enters “R” when the input device is fixed in the second position. Moreover, Some of the keys ( 32 ) are used to input functional options such that the key ( 32 ), originally used to input “#”, acts as a function key “Fn”. FIG. 5 is a three-dimensional diagram of the mobile phone of the second embodiment, and FIG. 6 is a lateral view of the mobile phone of the second embodiment. In FIG. 5 and FIG. 6 , the front view of the mobile phone of the second embodiment is the same as the mobile phone of the first embodiment. When the input device ( 20 ) of the first embodiment is fixed in the first position, the main body ( 1 ) completely covers the front side and back side of the hidden portion ( 40 ). In FIG. 5 and FIG. 6 , however, when the input device ( 20 ) of the second embodiment is fixed in the first position, the main body ( 10 ) does not cover the backside of the hidden portion ( 40 ), but only covers the second input elements, which comprises a plurality of keys ( 42 ) and a touch pad ( 44 ). Therefore, the structure of the present invention is not limited to the structure mentioned above. The feature of present invention is that the main body ( 10 ) covers the second input elements of the hidden portion ( 40 ) when the input device ( 20 ) is fixed in the first position, and the hidden portion ( 40 ) is exposed when the input device ( 20 ) is fixed in the second position. FIG. 7 is a partial section view of the input keyboard in the first position of the third embodiment, and FIG. 8 is a partial section view of the input keyboard in the second position of the third embodiment. In FIG. 7 and FIG. 8 , the structure of the third embodiment is similar to the structure of the first embodiment. In the third embodiment, the input device ( 20 ) of the mobile phone ( 1 ) comprises a flexible printed circuit board (FPC) ( 60 ), and the main body ( 10 ) comprises a first node ( 70 ) and a second node ( 80 ). The flexible printed circuit board ( 60 ) is used to transmit the signal from the input device ( 20 ) through the first node ( 70 ) or the second node ( 80 ) to the main body ( 10 ). In FIG. 7 , the flexible printed circuit board ( 60 ) conducts to the first node ( 70 ) when the input device ( 20 ) is fixed in the first position so that the first node ( 70 ) of the main body ( 10 ) receives only the signals including “1”, “2”, “3”, “4”, “5”, “6”, “7”, “8”, “9”, “0”, “*”, and “#”. In FIG. 8 , the flexible printed circuit board ( 60 ) conducts to the second node ( 80 ) when the input device ( 20 ) is fixed in the second position so that the second node ( 80 ) of the main body ( 10 ) receives the signal from the complete alphabetical keyboard made up by the visible portion ( 30 ) and a hidden portion ( 40 ) such as alphabetical characters, “A” to “Z”, or specific function keys, “Fn” or “CAP”. While the invention has been described by way of example and in terms of the preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
A mobile phone with a hidden input device. The mobile phone comprises a main body, and an input device coupled to the main body to input data and rotatably connected to the main body between a first position and a second position by a rotating device, wherein the input device has a visible portion with a plurality of first input elements covered by the main body when the input device is fixed in the first position, and a hidden portion with a plurality of second input elements appearing when the input device is fixed in the second position.
7
CROSS-REFERENCE TO RELATED APPLICATION The present application claims the benefit of U.S. Provisional Application No. 60/285,664, filed Apr. 23, 2001, and incorporated herein by reference. FIELD OF THE INVENTION The present invention relates to circular knitting machines and to methods for knitting fabrics on circular knitting machines. In particular, the present invention relates to coordinating the selective reciprocation of the needles and sinkers to counteract “robbing back” of a lay-in yarn. BACKGROUND OF THE INVENTION Circular knitting machines are widely used to produce knitted fabric, such as knitted fabric that is tubular. A conventional circular knitting machine includes a vertically extending cylinder, and multiple sinkers and latch needles that extend around and move relative to the upper end of the cylinder. The sinkers reciprocate radially and the latch needles reciprocate vertically in a cooperative fashion to produce knitted fabric. Circular knitting machines are used to make many types of fabric, including jersey and fleece fabrics. For example, prior fleece fabrics of the type used in sweatshirts have floating portions of lay-in yarn extending above the “face” of the base fabric structure. Knitted fleece fabrics are usually grouped in the categories of three-end fleeces and two-end fleeces. It is known to knit three-end fleeces on a circular knitting machine specifically designed to produced this type of fabric. In these machines, two yarns are knitted and one is laid in, and the sinkers are typically double-nosed. The double nosed sinkers are used individually to allow for more lay-in yarn to be measured in. However, these machines are specialized machines that are not readily transformable from standard raceway machines. In contrast, it is known to knit two-end fleeces on circular knitting machines with standard raceways. Two-end fleeces are typically produced by the use of single-nosed sinkers. In this instance, the length of the lay-in yarn may be measured by drawing the respective needle below the sinker knitting platform, sometimes in combination with the sinker throat pushing the lay-in yarn around the needle shaft. Two-end fleeces formed in this manner are generally used for less expensive sweatshirt-styled fabrics. Whereas it is conventional to use a basic single-knit raceway machine having single throat sinkers to produce fleece fabrics, there is a limitation as to the amount of lay-in yarn that can be introduced. Typically, the amount of land or flat in the stitch cam associated with a lay-in feed is not sufficient to counteract severe robbing back of the amount of lay-in yarn being fed. Likewise, even though lowering the stitch cam on a standard raceway, two-end fleece machine increases the amount of lay-in yarn incorporated into the fabric, it is common for the stitch cam to be lowered as far as possible in an effort to maximize the amount of lay-in yarn incorporated into the fabric. This can jeopardize the quality of the fabric, because unwanted holes in the fabric can be formed by breaking the yarn of the previous stitch not knitted off by the tucking needle. Likewise, the welt cams on the lay-in feeds can also rupture stitches if the welt cams are attached to the same stitch cam post that holds the tuck cam (as is normal), and that post is adjusted for a deep draw for the tuck cam. In the past, special machines for manufacturing two-end fleece have been built by Vanguard Supreme Knitting Machine Company, a division of Monarch Knitting Machine Corp. These special machines introduce lay-in yarn with a double nosed sinker, and the amount of lay-in yarn is respectively measured by the distance that the upper throats of the sinkers push the lay-in yarn around the needle shanks. However, these machines, like three-end fleece machines, are specialized machines that are not readily transformable from standard raceway knitting machines. Accordingly, there is a need for methods and apparatus that provide improved countermeasures against robbing back, such as for standard raceway knitting machines, so that high quality fleece fabric can be produced on standard raceway knitting machines. SUMMARY OF THE INVENTION In accordance with one aspect, the present invention relates to a method and apparatus for producing a knitted fabric having a lay-in yarn, and more specifically the invention relates to a modification that may be incorporated with minimal added expense into both existing and new raceway-type knitting machines, so that they can produce fabric having the desired lay-in yarn feature. In accordance with one aspect of the present invention, a circular knitting machine includes multiple needles arranged for reciprocating in the direction of the axis of the machine, and needle cam tracks arranged around the axis for respectively engaging butts of the needles so that one or more intervening needles of the needles are positioned between at least a pair of the needles, with the intervening needle(s) preferably including all of the needles positioned between the pair of needles. During a predetermined period, the pair of needles engage and draw down a lay-in yarn and hold portions of the lay-in yarn in a lower position, and the intervening needle(s) do not draw down the lay-in yarn. Preferably the intervening needle(s) are substantially maintained in a welt position and do not substantially interact with the lay-in yarn during the predetermined period. The knitting machine also includes multiple sinkers arranged for moving radially relative to the axis, and at least one sinker cam track arranged around the axis for selectively engaging and moving the sinkers. The sinkers are moved so that during the predetermined period, there are one or more intervening sinkers of the sinkers that are positioned between the pair of needles and arranged in a forward position. As a result, the section of the lay-in yarn that spans between the pair of needles is retained over the nib(s) of the intervening sinker(s) positioned between the pair of needles. Preferably the section of the lay-in yarn that spans between the pair of needles is contemporaneously retained over all of the nib(s) of the intervening sinker(s) positioned between the pair of needles. This advantageously counteracts robbing back of the lay-in yarn. In accordance with one aspect of the present invention, a set of cam tracks for a circular knitting machine is provided, and preferably the cam tracks can be used in standard raceway knitting machines so that these machines can advantageously produce a high quality fleece fabric. In accordance with this aspect, the set includes multiple needle cam tracks that provide the above-described arrangement and operation of the needles, and at least one sinker cam track for moving the sinkers as described above. Preferably each of the cam tracks includes multiple cams that are capable of being removably mounted to the knitting machine. In accordance with one aspect of the present invention, the multiple needle cam tracks include a first needle cam track for engaging the butts of the pair of needles for controlling the pair of needles during the predetermined period, and a second needle cam track for engaging the butts of the intervening needle(s) for controlling the intervening needle(s) during the predetermined period. In accordance with one aspect of the present invention, a method of knitting a fleece fabric is provided. In accordance with this aspect, a lay-in yarn and a jersey yarn are introduced into a circular knitting machine. A base fabric structure is formed from the jersey yarn by operating at least some of the needles and sinkers of the machine. In addition, the lay-in yarn is connected to the base fabric structure so that floating portions of the lay-in yarn extend above a face of the base fabric structure. The floats (i.e., floating portions of the lay-in yarn) are formed by operating the above-discussed pair of needles to engage, draw down, and hold portions of the lay-in yarn in a lower position during the predetermined period. At the same time, the above-discussed intervening needle(s) are preferably substantially maintained in a welt position such that the intervening needle(s) do not substantially interact with the lay-in yarn during the predetermined period. In addition, the above-discussed intervening sinker(s) are arranged in a forward position during the predetermined period, so that the section of the lay-in yarn that spans between the pair of needles is retained over the nib(s) of the intervening sinker(s). Preferably the section of the lay-in yarn that spans between the pair of needles is contemporaneously retained over all of the nibs of the intervening sinkers. This advantageously at least partially counteracts robbing back of the lay-in yarn. BRIEF DESCRIPTION OF THE DRAWINGS Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: FIG. 1 diagrammatically illustrates a portion of a circular knitting machine, in accordance with an exemplary embodiment of the present invention; FIG. 2 illustrates sinker cams of the machine of FIG. 1; and FIGS. 3A-E are partial views of the machine of FIG. 1 that diagrammatically illustrate the positioning of the sinkers relative to the needles, feeds and yarns during the knitting process, respectively at selected points A-E of FIGS. 1-2, in accordance with the exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which one or some, but not all embodiments are shown. Indeed, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. Generally described primarily with reference to FIG. 1, one aspect of the present invention is the modification of a standard raceway-type knitting machine by altering the needle and sinker camming so as to provide a knitting machine 10 in which a substantial length of lay-in yarn 12 is preferably contemporaneously suspended over the tops of the noses 14 of multiple adjacent sinkers 16 in a manner that counteracts the “robbing back” action of the lay-in yarn as the needles 18 holding the lay-in yarn descend to the knitting position. In the knitting position, the needles 18 holding the lay-in yarn 12 knit it to the base fabric structure, which is knitted from jersey yarn 20 . Briefly described in accordance with the exemplary embodiment of the present invention, predetermined needle camming, namely cam 22 , is advanced (relative to the sinker camming shown in FIG. 2 ), and predetermined sinker camming is retarded relative to the needle camming (as compared to the customary relationship), so that the needles 18 that knit in the lay-in yarn 12 are drawn down from a tuck position to the lower stitch draw position while the associated sinkers 16 remain pushed forward. Only a representative few of the needles 18 and sinkers 16 are identified by their reference numerals in FIG. 1, in an effort to clarify the drawing. More specifically, the knitting machine 10 is provided with two or more needle cam tracks, designated herein as Track 1 , Track 2 , Track 3 , and so on. Only portions of Tracks 1 and 2 are shown in FIG. 1, and they are respectively identified by the reference characters “T1” and “T2” in FIG. 1 . Preferably four needle cam tracks are provided in the machine 10 , with the tuck cams located on Track 1 and Track 3 . FIG. 1 shows that in the exemplary embodiment, and for purposes of illustrating the present invention but without limitation, the needles are arranged so that a sequence of three needles is run in (i.e., have butts that extend into) Track 2 , while every fourth needle is run in (i.e., has a butt that extends into) Track 1 . Other combinations are contemplated using, for example, sequences with larger or smaller numbers of needles. For illustrative purposes in FIG. 1, the needles that are run in Track 1 do not extend down to Track 2 , and the needles that are run in Track 2 do extend to Track 2 . The direction of needle movement through the machine 10 is indicated by an arrow 24 in FIG. 1 . In accordance with the exemplary embodiment, all of the needles 18 receive the jersey yarn 20 from feed 26 , and then the needles proceed to knit a jersey stitch. Thereafter, the needles 18 that are not to pick up the lay-in yarn 12 at feed 28 go into a welt position on Track 2 , due to the interaction between the cam 30 and the butts of the needles that are not to pick up the lay-in yarn. The needles 18 designated to pick up the lay-in yarn 12 are raised to the tuck position by the interaction of their butts and cam 22 . Thereafter, the needles 18 designated to pick up the lay-in yarn 12 immediately descend, pulling the lay-in yarn 12 down over the tops of the nibs or noses 14 of the sinkers 16 that are left in an extended forward position by sinker cam 34 (FIG. 2 ). A portion of a sinker cam track that includes cams 34 , 36 and 38 is shown in FIG. 2 . An example of the relative positioning of the cams, sinkers 16 , needles 18 , and feeds 26 and 28 may be seen by comparing points designated by A, B, C, D and E in FIGS. 1-2 respectively with FIGS. 3A-E. That is, FIGS. 3A-E respectively illustrate the positioning of the sinkers 16 relative to the needles 18 , yarns 12 and 20 , and feeds 26 and 28 at selected points A-E during the knitting process, with the points A-E being designated in FIGS. 1-2. FIGS. 3A-E also illustrate the relative positions of the sinkers 16 with respect to one another at the points A-E. That is, the needles 18 are in a generally cylindrical arrangement; therefore, the vertical positioning of the needles in FIGS. 3A-E provides a common frame of reference. In FIGS. 3A-E, vertical arrows in close proximity to the needles 18 indicate the direction of movement of the needles. Likewise, horizontal arrows in close proximity to the sinkers 16 in FIGS. 3A-E indicate direction of movement of the sinkers, with a sinker not moving in the radial direction if there is no horizontal arrow closely associated therewith. As illustrated in FIGS. 3A and 3B, needles 18 engage and draw down the jersey yarn 20 so as to form knitted loops of a base fabric structure 40 . The sinkers 16 retract between points A and B. When the needles 18 reach point C, the sinkers 16 have returned to a forward position and the lay-in yarn 12 is engaged by the needles that are running with butts in Track 1 . At this point, the nose 14 of the sinker remains forward so that the drawing down of the needle 18 with the lay-in yarn 12 carries the lay-in yarn over the top of the sinker nose 14 . As best seen in FIG. 1, since every fourth needle 18 draws down the lay-in yarn 12 and since the noses 14 remain forward from point C until past point D, the drawing down of every fourth needle pulls the lay-in yarn over the noses of four adjacent sinkers 16 . When the needles reach points C and D, they are below the knitting platform surfaces 44 (FIG. 3E) of the sinkers 16 . Referring to FIG. 1, the horizontal broken line 46 illustrates the position of the knitting platform surfaces 44 of all of the sinkers 16 of the machine 10 , which can be characterized as the lowest knitting platform of the machine 10 . As apparent from the foregoing, in accordance with the exemplary embodiment of the present invention, a pair of needles 18 pulls the lay-in yarn 12 down to a lower position that is at or below the lowest knitting platform, which is defined by the knitting platform surfaces 44 , so that the section of the lay-in yarn that spans between the pair of needles simultaneously extends over noses 14 of multiple adjacent sinkers 16 (i.e., a group of intervening sinkers) that are positioned between the pair of needles and are maintained in a forward position sufficiently long so that robbing-back is at least partially counteracted. In other embodiments of the present invention, the pair of needles 18 pull the lay-in yarn 12 to other lower positions, such as, but not limited to, lower positions that are above, below, or even with the knitting platform surfaces 44 or other portions of the sinkers 16 . Preferably the section of the lay-in yarn 12 that spans between the pair of needles 18 extends simultaneously over noses 14 of at least three adjacent intervening sinkers 16 , and most preferably over four or at least four adjacent intervening sinkers, and in the embodiment of the present invention shown in the drawings, each intervening group of sinkers includes four sinkers. Alternatively, each intervening group of sinkers 16 may include more than four sinkers, or there may be only one intervening sinker positioned between each pair of needles 18 that pulls the lay-in yarn 12 down to the lower position, although typically there would be at least two intervening sinkers positioned between each pair of needles that pulls the lay-in yarn down to the lower position. Generally described with respect to each pair of needles 18 that pulls the lay-in yarn 12 down to the lower position, there are one or more intervening sinkers 16 that are positioned between the pair of needles and are arranged in a forward position so that a section of the lay-in yarn that spans between the pair of needles is temporarily retained over one or more nibs 14 of the one or more intervening sinkers. In accordance with the exemplary embodiment, one or more intervening needles of the needles 18 are positioned between the pair of needles; and these intervening needle(s) are substantially maintained in a welt position and do not hold the lay-in yarn in the welt position. The intervening needle(s) 18 preferably may include five needles or more, four or at least four needles, three or at least three needles, two needles, or only one needle, and in the embodiment of the present invention shown in the drawings, each intervening group of needles includes three needles. Because the lay-in yarn 12 spanning between the pair of needles 18 is contemporaneously pulled over the tops of one or more noses 14 , an extra length of lay-in yarn is advantageously consumed so as to counteract the robbing back that normally occurs when lay-in yarn is carried by the needle hooks as the needles descend in the knitting machine. While some degree of robbing back still normally occurs in a knitting machine having the features of the present invention, the added length of the lay-in yarn exceeds the amount given up to robbing back. Thus, the amount and/or height of the floats 42 (a representative few of which are identified by their reference numeral in FIGS. 3 D-E), which are floating portions of the lay-in yarn 12 , is greater than otherwise would result. The present invention advantageously allows for the manufacture of, and includes a method of manufacturing, a fleece fabric that can be, but is not required to be, formed on standard raceway knitting machines. In accordance with one aspect of the present invention, relatively large amounts of lay-in yarn are introduced into the fabric being formed, which results in the fabric being more easily brushed or napped for producing a denser and/or more lofty fleece. In accordance with one aspect of the present invention, only a single pass through a brushing or napping machine may be required to obtain the desired result. Sinkers with different height nibs or noses and/or nose lengths may be used to help determine the range of lay-in yarn amounts put into the fabric. One feature of the present invention is advantageously embodied in a set of cam tracks for being used with/retrofitted to a conventional, standard raceway knitting machine, such that the set of cam tracks transform the conventional, standard raceway knitting machine into the above-described knitting machine 10 . Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
A circular knitting machine has sinkers arranged for radially reciprocating around an upper portion of a cylinder, and latch needles arranged around the upper portion's perimeter for reciprocating along the axis of the cylinder. Selected ones of the needles draw down a lay-in yarn while the sinkers between the selected needles remain in a pushed forward position, so that the lay-in yarn overrides the nibs of the sinkers. In a preferred embodiment, each forth needle, and only each fourth needle, is selected to draw down a lay-in yarn, and four sinkers are positioned between each adjacent pair of the selected needles so that the lay-in yarn overrides four nibs between each draw down. The selected and non-selected needles engage jersey yarns at other knitting stations. This circular knitting machine can be adapted from existing knitting machines.
3
CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to provisional application U.S. Ser. No. 62/221,425, titled “Method of Operating a Hydrogen Dispensing Unit,” filed Sep. 21, 2015, and provisional application U.S. Ser. No. 62/245,007, titled “Method of Operating a Hydrogen Dispensing Unit,” filed Oct. 22, 2015, the contents of which are hereby incorporated by reference. BACKGROUND The present invention relates to a method of operating a hydrogen dispensing unit. The present invention more particularly relates to a method of operating a hydrogen dispensing unit where the hydrogen is cooled prior to dispensing the hydrogen to a hydrogen storage tank in a vehicle. Hydrogen dispensing units are used to dispense high pressure hydrogen into hydrogen storage tanks in vehicles such as cars, buses, trucks, and forklifts. There is growing interest to use hydrogen as a transportation fuel in cars, buses, trucks, and other vehicles. Hydrogen is generally stored in a fuel tank on-board the vehicles at high pressure. After most of the on-board hydrogen has been depleted, the pressure of the hydrogen in the fuel tank is reduced and the fuel tank must be refueled with hydrogen. During refueling, hydrogen is dispensed into the fuel tank at a hydrogen dispensing station. The dispensing station includes a hydrogen supply, which can be one or more high pressure storage tanks. Hydrogen is transferred from the high pressure storage tank into the fuel tank of the vehicle. The driving force for transferring hydrogen is the pressure difference between the high pressure storage tank and the vehicle fuel tank. Dispensing from a high pressure supply vessel to the lower pressure receiving vessel in a vehicle results in a temperature increase of the hydrogen that was dispensed. To compensate for the temperature rise of the dispensed hydrogen, hydrogen dispensing stations may include one or more heat exchangers to cool the hydrogen as it is being dispensed. Cooling may be provided by a refrigerant in a refrigeration cycle. The heat exchanger may comprise one or more high thermal capacity cooling blocks, which are cooled by the refrigerant and through which the hydrogen passes and is cooled. The transfer line between the high pressure storage tank and the fuel tank typically includes various control valves, and block and bleed valves. A block valve blocks the flow from the high pressure storage tank and a bleed valve allows a portion of the hydrogen trapped between the block valve and the dispensing nozzle to discharge, thereby reducing the pressure at the dispensing nozzle. Accepted standards, such as SAE J2600 and ISO 17268, require that the pressure at the nozzle be less than 0.5 MPa (gauge) before the dispensing nozzle can be disconnected from the fueling receptacle on the vehicle. While the transfer line between the block valve and the dispensing nozzle will be at a lower pressure after dispensing hydrogen to a vehicle, the residual hydrogen trapped in the transfer lines between the control valve and one or more block valves will still be at high pressure and a cold temperature because of being cooled in the heat exchanger. As the hydrogen dispension unit sits idle waiting to refuel another vehicle, the temperature of the residual trapped hydrogen will increase resulting in a pressure increase in the lines. The resulting pressure increase may be greater than design pressure limits for the equipment. The resulting high pressure may cause the dispensing unit to trip because of protections configured to protect the vehicle from excessive pressure, or because the excessive pressure might be interpreted by the controller as some sort of pressure transducer failure. Pressure relief valves could be used to relieve the pressure when it exceeds safe limits, but pressure relief valves are known for failing to completely reseal after relieving the pressure. Use of pressure relief valves on a frequent basis is undesirable. Industry desires reliable hydrogen dispensing units. BRIEF SUMMARY The present invention relates to a method for operating a hydrogen dispensing unit. There are several aspects of the invention as outlined below. In the following, specific aspects of the invention are outlined. The reference numbers and expressions set in parentheses are referring to an example embodiment explained further below with reference to FIG. 1 . The reference numbers and expressions are, however, only illustrative and do not limit the aspect to any specific component or feature of the example embodiment. The aspects can be formulated as claims in which the reference numbers and expressions set in parentheses are omitted or replaced by others as appropriate. Aspect 1. A method of operating a hydrogen dispensing unit ( 1 ) comprising: dispensing hydrogen from a supply vessel ( 102 ) to a receiving vessel ( 118 or 218 ) via the hydrogen dispensing unit ( 1 ), the hydrogen dispensing unit ( 1 ) comprising a heat exchanger ( 106 ) to cool the hydrogen prior to the hydrogen being dispensed into the receiving vessel ( 118 or 218 ), said dispensing continuing until a target quantity of hydrogen is dispensed and thereupon terminating said dispensing; wherein upon terminating said dispensing, a first quantity of hydrogen is trapped within a first one or more conduits ( 130 , 132 , 232 , 233 ), the first one or more conduits operatively connecting a plurality of valves, the plurality of valves including a control valve ( 104 ) and a block valve ( 108 or 208 ), said first quantity of hydrogen being trapped upon closing said plurality of valves, at least a portion of the first quantity of hydrogen having been cooled in said heat exchanger ( 106 ), the first quantity of hydrogen exerting a pressure in the first one or more conduits ( 130 , 132 , 232 , 233 ); measuring the pressure of the first quantity of hydrogen in the first one or more conduits ( 130 , 132 ); opening and subsequently closing the block valve ( 108 or 208 ) when the pressure of the first quantity of hydrogen equals or exceeds a selected pressure thereby removing a fraction of the first quantity of hydrogen from the first one or more conduits ( 130 , 132 , 232 , 233 ) and transferring the fraction of the first quantity to a second one or more conduits ( 134 , 136 or 234 , 236 ), the second one or more conduits ( 134 , 136 or 234 , 236 ) operatively connected to the block valve ( 108 or 208 ) and a bleed valve ( 114 or 214 ); and opening and subsequently closing the bleed valve ( 114 or 214 ) thereby discharging a first quantity of vented hydrogen from the second one or more conduits ( 134 , 136 or 234 , 236 ). Aspect 2. The method of aspect 1 wherein the first quantity of vented hydrogen comprises at least a portion of the fraction of the first quantity of hydrogen. Aspect 3. The method of aspect 1 or aspect 2 wherein during the steps of opening and subsequently closing the block valve ( 108 or 208 ) and opening and subsequently closing the bleed valve ( 114 or 214 ), the block valve ( 108 or 208 ) is opened at the same time as the bleed valve ( 114 or 214 ) is opened and the block valve ( 108 or 208 ) closed at the same time as the bleed valve ( 114 or 214 ) is closed. Aspect 4. The method of aspect 1 or aspect 2 wherein during the steps of opening and subsequently closing the block valve ( 108 ) and opening and subsequently closing the bleed valve ( 114 ), the bleed valve ( 114 ) is opened and subsequently closed after the block valve ( 108 ) is opened and subsequently closed. Aspect 5. The method of any one of the preceding aspects wherein at least a portion of the first quantity of hydrogen has an initial temperature less than −17.5° C. or less than −33° C. upon first being trapped. Aspect 6. The method of any one of the preceding aspects wherein the control valve ( 104 ) is a pressure control valve, programmable pressure regulator, or a dome loaded regulator. Aspect 7. The method of any one of the preceding aspects wherein upon terminating said step of dispensing, a second quantity of hydrogen is trapped within the second one or more conduits ( 234 , 236 ), the second one or more conduits ( 234 , 236 ) operatively connecting the block valve ( 208 ), the bleed valve ( 214 ), and a second block valve ( 226 ); wherein the first quantity of vented hydrogen comprises a fraction or all of the second quantity of hydrogen. Aspect 8. The method of any one of aspects 1 to 6 wherein upon terminating said step of dispensing, a second quantity of hydrogen is trapped within the second one or more conduits ( 234 , 236 ), the second one or more conduits ( 234 , 236 ) operatively connecting the block valve ( 208 ), the bleed valve ( 214 ), and a second block valve ( 226 ), the second quantity of hydrogen exerting a pressure in the second one or more conduits ( 234 , 236 ), the method further comprising: measuring the pressure of the second quantity of hydrogen in the second one or more conduits ( 234 , 236 ); and opening and subsequently closing the bleed valve ( 214 ) when the pressure of the second quantity of hydrogen equals or exceeds a selected pressure thereby discharging a fraction or all of the second quantity of hydrogen from the second one or more conduits ( 234 , 236 ). Aspect 9. The method of aspect 7 or aspect 8 wherein upon terminating said step of dispensing, a third quantity of hydrogen is trapped within a third one or more conduits ( 235 ), the third one or more conduits ( 235 ) operatively connecting the second block valve ( 226 ) and a dispensing nozzle ( 210 ) having an internal valve, the third quantity of hydrogen exerting a pressure in the third one or more conduits ( 235 ), the method further comprising; measuring the pressure of the third quantity of hydrogen in the third one or more conduits ( 235 ); and opening and subsequently closing the second block valve ( 226 ) when the pressure of the third quantity of hydrogen equals or exceeds a selected pressure thereby removing a fraction of the third quantity of hydrogen from the third one or more conduits ( 235 ) and transferring the fraction of the third quantity to the second one or more conduits ( 234 , 236 ); and opening and subsequently closing the bleed valve ( 214 ) thereby discharging at least a portion of the fraction of the third quantity of hydrogen from the second one or more conduits ( 234 , 236 ). Aspect 10. The method of aspect 7 or aspect 8 wherein upon terminating said step of dispensing, a third quantity of hydrogen is trapped within a third one or more conduits ( 235 ), the third one or more conduits ( 235 ) operatively connecting the second block valve ( 226 ) and a dispensing nozzle ( 210 ) having an internal valve, the method further comprising: opening and subsequently closing the second block valve ( 226 ) thereby removing a fraction of the third quantity of hydrogen from the third one or more conduits ( 235 ) and transferring the fraction of the third quantity to the second one or more conduits ( 234 , 236 ), wherein during the steps of opening and subsequently closing the second block valve ( 226 ) and opening and subsequently closing the block valve ( 208 ), the second block valve ( 226 ) is opened at the same time as the block valve ( 208 ) is opened and the second block valve ( 226 ) is closed at the same time as the block valve ( 208 ) is closed. Aspect 11. The method of aspect 10 wherein during the steps of opening and subsequently closing the block valve ( 208 ) and opening and subsequently closing the bleed valve ( 214 ), the block valve ( 208 ) is opened at the same time as the bleed valve ( 214 ) is opened and the block valve ( 208 ) closed at the same time as the bleed valve ( 214 ) is closed. Aspect 12. The method of any one of the preceding aspects wherein the receiving vessel is a first receiving vessel of a series of receiving vessels, the method comprising: connecting and disconnecting the hydrogen dispensing unit ( 1 ) to and from the first receiving vessel ( 118 or 218 ) of the series of receiving vessels ( 118 or 218 ); and discharging the first quantity of vented hydrogen through the bleed valve ( 114 or 214 ) after having dispensed hydrogen to the first receiving vessel ( 118 or 218 ) of the series of receiving vessels ( 118 or 218 ) and before dispensing hydrogen to a subsequent second receiving vessel of the series of receiving vessels ( 118 or 218 ). Aspect 13. The method of any one of the preceding aspects wherein the first quantity of hydrogen is trapped within the first one or more conduits ( 130 , 132 , 232 , 233 ) between the control valve ( 104 ) and the block valve ( 108 or 208 ). Aspect 14. The method of any one of the preceding aspects wherein the control valve ( 104 ) is disposed upstream of the heat exchanger ( 106 ). Aspect 15. The method of any one of the preceding aspects wherein the block valve ( 108 or 208 ) is disposed downstream of the heat exchanger ( 106 ). Aspect 16. The method of any one of the preceding aspects comprising limiting the pressure of the hydrogen with a pressure regulator ( 206 ) disposed in the first one or more conduits ( 232 , 233 ) between the control valve ( 104 ) and the block valve ( 208 ). Aspect 17. A method for determining leakage in a control valve ( 104 ) of a hydrogen dispensing unit ( 1 ), the method comprising: dispensing hydrogen from a supply vessel ( 102 ) to a receiving vessel ( 118 or 218 ) via the hydrogen dispensing unit ( 1 ), the hydrogen dispensing unit ( 1 ) comprising a heat exchanger ( 106 ) to cool the hydrogen prior to the hydrogen being dispensed into the receiving vessel ( 118 or 218 ), said dispensing continuing until a target quantity of hydrogen is dispensed and thereupon terminating said dispensing; wherein upon terminating said dispensing, a first quantity of hydrogen is trapped within a first one or more conduits ( 130 , 132 , 232 , 233 ), the first one or more conduits operatively connecting a plurality of valves, the plurality of valves including a control valve ( 104 ) and a block valve ( 108 or 208 ), said first quantity of hydrogen being trapped upon closing said plurality of valves, at least a portion of the first quantity of hydrogen having been cooled in said heat exchanger ( 106 ), the first quantity of hydrogen exerting a pressure in the first one or more conduits ( 130 , 132 , 232 , 233 ); measuring the pressure of the first quantity of hydrogen in the first one or more conduits ( 130 , 132 ) thereby determining a measured pressure increase; comparing the measured pressure increase with an expected pressure increase (due to the temperature rise); and determining whether the control valve ( 104 ) is leaking responsive to comparing the measured pressure increase with the expected pressure increase. Aspect 18. The method of the preceding aspect wherein the receiving vessel is a first receiving vessel of a series of receiving vessels, the method comprising: connecting and disconnecting the hydrogen dispensing unit ( 1 ) to and from the first receiving vessel ( 118 or 218 ) of the series of receiving vessels ( 118 or 218 ); and determining whether the control valve ( 104 ) is leaking responsive to comparing the measured pressure increase with the expected pressure increase after having dispensed hydrogen to the first receiving vessel of the series of receiving vessels ( 118 or 218 ) and before dispensing hydrogen to a subsequent second receiving vessel of the series of receiving vessels ( 118 or 218 ). Aspect 19. The method of any one of the preceding aspects wherein the receiving vessel ( 118 or 218 ) is a fuel tank of a land vehicle such as a car, bus, truck, motorcycle, forklift, agricultural vehicle, construction machine, and a locomotive, or of an aircraft. BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS The FIGURE shows a process flow diagram for a hydrogen dispensing unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The ensuing detailed description provides preferred exemplary embodiments only, and is not intended to limit the scope, applicability, or configuration of the invention. Rather, the ensuing detailed description of the preferred exemplary embodiments will provide those skilled in the art with an enabling description for implementing the preferred exemplary embodiments of the invention, it being understood that various changes may be made in the function and arrangement of elements without departing from scope of the invention as defined by the claims. The articles “a” and “an” as used herein mean one or more when applied to any feature in embodiments of the present invention described in the specification and claims. The use of “a” and “an” does not limit the meaning to a single feature unless such a limit is specifically stated. The article “the” preceding singular or plural nouns or noun phrases denotes a particular specified feature or particular specified features and may have a singular or plural connotation depending upon the context in which it is used. The adjective “any” means one, some, or all indiscriminately of whatever quantity. The term “and/or” placed between a first entity and a second entity means one of (1) the first entity, (2) the second entity, and (3) the first entity and the second entity. The term “and/or” placed between the last two entities of a list of 3 or more entities means at least one of the entities in the list including any specific combination of entities in this list. The term “plurality” means “two or more than two.” The phrase “at least a portion” means “a portion or all.” As used herein, “first,” “second,” “third,” etc. are used to distinguish from among a plurality of steps and/or features, and is not indicative of the total number, or relative position in time and/or space unless expressly stated as such. As used herein, “in fluid flow communication” means operatively connected by one or more conduits, manifolds, valves and the like, for transfer of fluid. A conduit is any pipe, tube, passageway or the like, through which a fluid may be conveyed. An intermediate device, such as a pump, compressor or vessel may be present between a first device in fluid flow communication with a second device unless explicitly stated otherwise. For the purposes of simplicity and clarity, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. As used herein, pressures are gauge pressures unless explicitly stated otherwise. The sole FIGURE is a process flow diagram for describing the method. The process flow diagram includes the dispensing unit 1 and receiving tanks 118 and 218 for two respective vehicles. The FIGURE shows two dispensing legs, one having a configuration suitable for dispensing hydrogen to moderate pressure (e.g. 35 MPa) and another having a configuration suitable for dispensing hydrogen to high pressure (e.g. 70 MPa). The configuration for dispensing to moderate pressure is shown for dispensing to receiving tank 218 and the configuration for dispensing to high pressure is shown for dispensing to receiving tank 118 . The present invention is suitable for a hydrogen dispensing unit having one, two, or more dispensing legs. The hydrogen dispensing unit comprises one or more hydrogen storage tanks 102 . The one or more hydrogen storage tanks can be any hydrogen storage tanks known in the art. The one or more hydrogen storage tanks may include a plurality of storage tanks suitable for cascade filling. The hydrogen dispensing unit comprises a control valve 104 operatively connected to the one or more storage tanks 102 via a transfer conduit 103 . Control valve 104 may be a pressure control valve, programmable pressure regulator, or a dome loaded regulator. Control valve 104 controls the rate of transferring hydrogen from the one or more storage tanks 102 to the receiving tank 118 or receiving tank 218 depending on which dispensing leg is being used. The control valve 104 may control the rate of transferring hydrogen as a pressure ramp rate (i.e. change in pressure per unit time). The control valve 104 is operatively connected to the controller 120 and receives control signals from controller 120 . The hydrogen dispensing unit comprises a heat exchanger 106 operatively connected to the control valve 104 via a transfer conduit 130 . Heat exchanger 106 cools the hydrogen as it is being dispensed from the one or more storage tanks 102 to the receiving tank 118 or receiving tank 218 . The heat exchanger 106 may include a thermal ballast (thermal capacitor) such as an aluminum block as known from US 2008/0185068. Multiple cooling blocks, as known from US 2014/0007975 may be used. A pressure relief valve 105 may be connected to conduit 130 to relieve the pressure in conduit 130 should the pressure exceed a maximum allowable pressure. The pressure leaving the heat exchanger 106 may be measured using a pressure sensor 107 . Pressure sensor 107 may be used during the controlled dispensing of the hydrogen, and to detect if the pressure in conduit 132 exceeds a desired maximum pressure. For the high pressure (e.g. 70 MPa) dispensing leg, the hydrogen dispensing unit comprises a block valve 108 and a bleed valve 114 operatively connected to the control valve 104 via transfer conduits 132 , 134 , and 136 . Block valve 108 may be constructed such that if it fails, it fails in the closed position. Bleed valve 114 may be constructed such that if it fails, it fails in the open position. The high pressure dispensing leg comprises a dispensing nozzle 110 operatively connected to the block valve 108 . The dispensing nozzle 110 can be any dispensing nozzle known in the art for hydrogen fuelling, particularly one suited for dispensing hydrogen to 70 MPa. The block valve 108 in combination with the bleed valve 114 are used to reduce the pressure in the dispensing nozzle 110 prior to disconnecting the dispensing nozzle 110 from the receptacle 112 of the vehicle as is known in the art of hydrogen fueling. It may be desired to maintain the pressure in transfer conduits 134 and 136 at about 0.3 MPa during idle periods. A pressure sensor 116 may be used to measure the pressure in the transfer conduits 134 and 136 . For the moderate pressure (e.g. 35 MPa) dispensing leg, the hydrogen dispensing unit may comprise a pressure regulator 206 , a block valve 208 , a bleed valve 214 , and a second block valve 226 operatively connected to the control valve 104 via transfer conduits 232 , 233 , 234 , and 236 . The pressure regulator 206 may limit the pressure to the moderate pressure dispensing leg to about 42 MPa. The moderate pressure dispensing leg comprises a dispensing nozzle 210 operatively connected to the block valve 226 . The dispensing nozzle 210 can be any dispensing nozzle known in the art for hydrogen fueling, particularly one suited for dispensing hydrogen to 35 MPa. For the moderate pressure (35 MPa) dispensing leg, the dispensing nozzle 210 may comprise an internal block and bleed valve manifold. The pressure at the nozzle may be relieved to a desired pressure before disconnecting from receptacle 212 and the pressure in the conduits 234 , 235 , 236 may be maintained at a pressure ranging from 35 MPa to 42 MPa during idle periods. Pressure sensors 238 and 216 may be used to measure the pressure in the respective transfer conduits. A pressure relief valve 228 and associated pressure sensor/transmitter 216 may be connected to conduit 235 . The pressure relief valve 228 may be set to relieve gas at any desired pressure for example a pressure ranging from 46 MPa to 50 MPa. A block valve is any valve that is capable of blocking the flow in both directions. Any suitable block valve known in the art of hydrogen fueling may be used. A bleed valve is any device that is capable of bleeding off a gas from the conduit to vent the conduit. Any suitable bleed valve known in the art of hydrogen fueling may be used. The hydrogen dispensing unit comprises a controller 120 operatively connected to the control valve 104 , the various block valves, bleed valves, and pressure sensors. The controller may be a computer, process logic controller (PLC), or the like. Controllers are ubiquitous in the art of hydrogen dispensing. The controller 120 may receive signals from the pressure sensors 107 , 116 , 238 and 216 and send control signals to the block valves 108 , 208 , and 226 and bleed valves 114 and 214 . Hydrogen-fueled vehicles comprise a receiving tank 118 or 218 , and a respective receptacle 112 or 212 . Receiving tank 118 and receptacle 112 may be for receiving high pressure hydrogen gas (e.g. up to 70 MPa) and receiving tank 218 and receptacle 212 may be for receiving moderate pressure hydrogen gas (e.g. up to 35 MPa). Receiving tanks may have internal pressure sensors for measuring the pressure of the hydrogen contained within the respective receiving tank. The pressure sensor may communicate wirelessly with controller 120 . Prior to dispensing hydrogen, the dispensing nozzle is connected to the receptacle of the vehicle, for example dispensing nozzle 110 to receptacle 112 or dispensing nozzle 210 to receptacle 212 . The method is first described for the high pressure (70 MPa) dispensing leg and is applicable for any dispensing leg having a similar configuration. The method comprises dispensing hydrogen from the one or more supply vessels 102 to receiving vessel 118 via the hydrogen dispensing unit 1 . The flow rate of hydrogen is controlled using control valve 104 . The hydrogen is passed through heat exchanger 106 to cool the hydrogen prior to the hydrogen being dispensed into the receiving vessel 118 . Dispensing continues until a target quantity of hydrogen is dispensed, and after the target quantity is transferred, dispensing is terminated. The target quantity may be set by the target pressure for the receiving vessel 118 such that dispensing is terminated upon reaching a target pressure. After the receiving tank 118 receives the target quantity, for example by reaching the target pressure, the flow is stopped by closing block valve 108 . Then the pressure in the transfer line between block valve 108 and the dispensing nozzle 110 is reduced, for example to about 0.3 MPa by bleeding off at least a portion of the residual gas in the transfer line via bleed valve 114 . When the pressure at the dispensing nozzle is sufficiently reduced, the dispensing nozzle is disconnected from the receptacle 112 . Upon terminating dispensing, a first quantity of cold hydrogen is trapped within conduits 130 and 132 between the control valve 104 and the block valve 108 . In order to prevent H 2 -containing gas losses, this residual H 2 -containing gas is not vented. The first quantity of hydrogen is trapped upon closing valves 104 and 108 and was cooled in heat exchanger 106 and therefore has a temperature of, for example, less than about −17.5° C. or less than about −33° C. The first quantity of exerts a pressure in conduits 130 and 132 . As the hydrogen dispensing unit sits idle waiting to fill another vehicle fuel tank, the temperature of the first quantity hydrogen in conduits 130 and 132 will increase. As the temperature rises, so too does the pressure. At the end of dispensing, the pressure in the transfer lines of the dispensing unit could be about 76 to 80 MPa. If the dispensing terminates with hydrogen at 80 MPa in the transfer lines and the temperature of the hydrogen rises from −33° C. to +25° C., the pressure increases to about 100 MPa, which is far above the maximum allowable pressure that can be transferred to a vehicle with a maximum pressure rating of 87.5 MPa. The method comprises measuring the pressure of the first quantity of hydrogen in conduits 130 and 132 , for example with pressure sensor 107 , as the temperature and pressure of the first quantity of hydrogen increases. The pressure sensor 107 is in signal communication with controller 120 and transmits a signal representative of the pressure to controller 120 . When the pressure of the first quantity of hydrogen equals or exceeds a selected pressure, for example a pressure ranging from 70 MPa to 87.5 MPa, the controller provides signal instructions to block valve 108 to open and subsequently close block valve 108 while control valve 104 is kept closed thereby removing a fraction of the first quantity of hydrogen from conduits 130 and 132 and transferring the fraction of the first quantity to conduits 134 and 136 . As a result, the pressure of the gas in conduits 130 and 132 is decreased. Conduits 134 and 136 are operatively connected to bleed valve 114 . The method comprises opening and subsequently closing the bleed valve 114 thereby discharging at least a portion of the fraction of the first quantity of hydrogen from conduits 134 and 136 . Block valve 108 and bleed valve 114 may be opened simultaneously and closed simultaneously. Alternatively, block valve 108 may be opened and subsequently closed, followed by bleed valve 114 being opened and subsequently closed. The method is now described for the moderate pressure (35 MPa) dispensing leg and is applicable for any dispensing leg having a similar configuration. The method comprises dispensing hydrogen from the supply vessel 102 to receiving vessel 218 via the hydrogen dispensing unit 1 . The hydrogen is passed through heat exchanger 106 to cool the hydrogen prior to the hydrogen being dispensed into the receiving vessel 218 . Dispensing continues until a target quantity of hydrogen is dispensed, and after the target quantity is transferred, dispensing is terminated. The target quantity may be set by the target pressure for the receiving vessel 218 such that dispensing is terminated upon reaching the target pressure. Upon terminating dispensing, a first quantity of cold hydrogen is trapped within conduits 130 , 232 and 233 , a second quantity of hydrogen is trapped within conduits 234 and 236 , and a third quantity of hydrogen is trapped within conduit 235 . The first quantity of hydrogen is trapped upon closing valves 104 and 208 and was cooled in heat exchanger 106 and therefore has a temperature of, for example, less than about −17.5° C. or less than about −33° C. The first quantity of exerts a pressure in conduits 130 , 232 , and 233 . The second quantity of hydrogen is trapped upon closing valves 208 and 226 and was also cooled in heat exchanger 106 and therefore has a temperature of, for example, less than about −17.5° C. or less than about −33° C. The second quantity of exerts a pressure in conduits 234 , and 236 . The third quantity of hydrogen is trapped upon closing block valve 226 and the dispensing nozzle 210 . Dispensing nozzle 210 has an internal valve. The third quantity of hydrogen was also cooled in heat exchanger 106 and therefore has a temperature of, for example, less than about −17.5° C. or less than about −33° C. The third quantity of hydrogen exerts a pressure in conduit 235 . As the hydrogen dispensing unit sits idle waiting to fill another vehicle fuel tank, the temperature of the first quantity hydrogen in conduits 130 , 232 , and 233 will increase, the temperature of the second quantity of hydrogen in conduits 234 and 236 will increase, and the temperature of the third quantity of hydrogen in conduit 235 will increase. As the temperature of the hydrogen rises, so too does the pressure of the hydrogen. The method comprises measuring the pressure of the first quantity of hydrogen in conduits 130 , 232 , and 233 , for example with pressure sensor 107 , as the temperature and pressure of the first quantity of hydrogen increases. The pressure sensor 107 is in signal communication with controller 120 and transmits a signal representative of the pressure to controller 120 . When the pressure of the first quantity of hydrogen equals or exceeds a first selected pressure, for example a pressure ranging from 70 MPa to 87.5 MPa, the controller provides signal instructions to block valve 208 to open and subsequently close block valve 208 while control valve 104 is kept closed thereby removing a fraction of the first quantity of hydrogen from conduits 130 , 232 , and 233 and transferring the fraction of the first quantity to conduits 234 and 236 . As a result, the pressure of the gas in conduits 130 , 232 , and 233 is decreased. In the example embodiment control valve 104 is closed upon terminating dispensing and kept closed during discharging trapped hydrogen. In alternative embodiments an additional blocking means such as a block valve may be disposed between supply vessel 102 and control valve 104 or between control valve 104 and heat exchanger 106 . In those embodiments the additional blocking means may be closed upon terminating dispensing and kept closed during discharging trapped hydrogen while control valve 104 is kept open, for example, in a minimum flow position. Conduits 234 and 236 are operatively connected to a bleed valve 214 . The method comprises opening and subsequently closing the bleed valve 214 thereby discharging at least a portion of the fraction of the first quantity of hydrogen and a fraction or all of the second quantity of hydrogen from conduits 234 and 236 . Bleed valve 214 may be opened before block valve 208 is opened or simultaneously with block valve 208 or after block valve 208 has been opened to remove a quantity of vented hydrogen from conduits 130 and 132 . The quantity of vented hydrogen may comprise at least a portion of the fraction of the first quantity of hydrogen in case the bleed valve 214 and block valve 208 are opened simultaneously or bleed valve 214 is opened after block valve 208 . In case bleed valve 214 is opened before block valve 208 , a portion of the hydrogen trapped in conduits 234 and 236 may be vented as the quantity of vented hydrogen thereby providing capacity for a fraction of the first quantity of hydrogen to be transferred to the second one or more conduits 234 and 236 . After removal of the quantity of vented hydrogen, bleed valve 114 may be closed simultaneously with block valve 108 or after block valve 108 has been closed. For example, block valve 208 and bleed valve 214 may be opened simultaneously and closed simultaneously, or aternatively, block valve 208 may be opened and subsequently closed, followed by bleed valve 214 being opened and subsequently closed. In case block valve 208 and bleed valve 214 are operated sequentially, the pressure in conduits 234 and 236 may be lower than in 232 and 233 for the transfer of the fraction of the first quantity of hydrogen due to an earlier discharge of hydrogen from bleed valve 214 . The method may further comprise measuring the pressure of the second quantity of hydrogen in conduits 234 and 236 , for example using pressure sensor 238 as the temperature of the second quantity of hydrogen increases. When the pressure of the second quantity of hydrogen equals or exceeds a second selected pressure, for example a pressure ranging from 35 to 44, the controller provides signal instructions to bleed valve 214 to open and subsequently close thereby discharging a fraction or all of the second quantity of hydrogen from conduits 234 and 236 . As a result, the pressure of the hydrogen in conduits 234 and 236 is decreased. The second selected pressure may be the same or different from the first selected pressure and, if different, may be lower than the first selected pressure. The method may comprise opening and subsequently closing block valve 226 thereby removing a fraction of the third quantity of hydrogen from conduit 235 and transferring a fraction of the third quantity of hydrogen to conduits 234 and 236 . Block valve 208 and block valve 226 may be opened simultaneously and closed simultaneously. Further, bleed valve 214 may be opened simultaneously with the opening of block valve 208 and block valve 226 , and bleed valve 215 may be closed simultaneously with the closing of block valve 208 and block valve 226 to vent the trapped hydrogen. The method may further comprise measuring the pressure of the third quantity of hydrogen in conduit 235 , for example using pressure sensor 216 as the temperature of the third quantity of hydrogen increases. When the pressure of the third quantity of hydrogen equals or exceeds a third selected pressure, for example a pressure ranging from 35 to 44, the controller provides signal instructions to block valve 226 to open and subsequently close thereby removing a fraction of the third quantity of hydrogen from conduit 235 and transferring the fraction of the third quantity of hydrogen to conduits 234 and 236 . As a result, the pressure of the hydrogen in conduit 235 is decreased. The third selected pressure may be the same or different than the first selected pressure and/or the second selected pressure. The method may then further comprise opening a closing the bleed valve 214 thereby discharging at least a portion of the fraction of the third quantity of hydrogen from conduits 234 and 236 . In another embodiment, the invention relates to a method for determining leakage in a control valve 104 of the hydrogen dispensing unit. The leak detection method comprises dispensing hydrogen from the one or more supply vessels 102 to receiving vessel 118 via the hydrogen dispensing unit 1 . The flow rate of hydrogen is controlled using control valve 104 . The hydrogen is passed through heat exchanger 106 to cool the hydrogen prior to the hydrogen being dispensed into the receiving vessel 118 . Dispensing continues until a target quantity of hydrogen is dispensed, and after the target quantity is transferred, dispensing is terminated. The target quantity may be set by the target pressure for the receiving vessel 118 such that dispensing is terminated upon reaching a target pressure. After the receiving tank 118 reaches a target pressure, the flow is stopped by closing block valve 108 . Then the pressure in the transfer line between block valve 108 and the dispensing nozzle 110 is reduced, for example to about 0.3 MPa by bleeding off at least a portion of the residual gas in the transfer line via bleed valve 114 . When the pressure at the dispensing nozzle is sufficiently reduced, the dispensing nozzle is disconnected from the receptacle 112 . Upon terminating dispensing, a first quantity of cold hydrogen is trapped within conduits 130 and 132 between the control valve 104 and the block valve 108 . In order to prevent H 2 -containing gas losses, this residual H 2 -containing gas is not vented. The first quantity of hydrogen is trapped upon closing valves 104 and 108 and was cooled in heat exchanger 106 and therefore has a temperature of, for example, less than −17.5° C. or less than −33° C. The first quantity of exerts a pressure in conduits 130 and 132 . As the hydrogen dispensing unit sits idle waiting to fill another vehicle fuel tank, the temperature of the first quantity hydrogen in conduits 130 and 132 will increase. As the temperature rises, so too does the pressure. The leak detection method comprises measuring the pressure of the first quantity of hydrogen in conduits 130 and 132 , for example with pressure sensor 107 , as the temperature and pressure of the first quantity of hydrogen increases thereby determining a measured pressure increase. The pressure sensor 107 is in signal communication with controller 120 and transmits a signal representative of the pressure to controller 120 . The leak detection method comprises comparing the measured pressure increase with an expected pressure increase. From the initial pressure in the conduits 130 and 132 and the initial temperature, an expected pressure increase can be calculated for an expected temperature rise of the trapped hydrogen. The leak detection method comprises determining whether the control valve ( 104 ) is leaking responsive to comparing the measured pressure increase with the expected pressure increase. The comparison may be done using controller 120 .
Method of operating a hydrogen dispensing where pressure relief is provided through block and bleed valves. After dispensing hydrogen from a dispensing station where the hydrogen is cooled during dispensing, trapped hydrogen remains in the transfer lines. During the idle time between refueling vehicles, the temperature of the trapped hydrogen increases resulting in an increase in the pressure of the trapped hydrogen. Block and bleed valves operate to relieve the pressure in the transfer lines.
5
FIELD OF THE INVENTION [0001] The present invention is drawn generally to the field of polypropylene resins. More specifically, the present invention is drawn to a polymer comprising high crystalline homopolymer polypropylene and a high ethylene content ethylene/propylene random copolymer. The present application is also drawn to methods of making the same as well as novel compositions, such as, but not limited to, biaxially-oriented polypropylene (“BOPP”) film comprising the polymer of the invention. BACKGROUND OF THE INVENTION [0002] One of the myriad of uses for polypropylene is for the production of BOPP film. BOPP is used to produce both clear and opaque film for numerous packaging applications. To gain wide commercial acceptance for BOPP film applications, though, a given polypropylene resin must provide uniform stretching under typical BOPP processing conditions. Not surprisingly, not all polypropylene resins exhibit favorable behavior under the mechanical and thermal stresses of the BOPP production process. One resin that tolerates BOPP production conditions is high xylene solubles homopolymer. This resin can be fractionated into three components: an isotactic component, a stereoblock component, and an atactic component. [0003] The stereoblock component is crystalline and melts at a significantly lower temperature than the isotactic component. Film processing performance of the resin, as measured by T. M. Long draw stress, is correlated with the amount and quality of the stereoblock component. The stereoblock component is also believed to provide softening that enables solid-phase drawing to occur under the practical draw stresses observed on a BOPP processing line. [0004] In high xylene solubles homopolymers, the stereoblock component is created by introducing defects which disrupt crystallization and provide a lower-melting component. These defects, however, compromise both the amount and the stereo regularity of the isotactic phase, reducing film strength. Traditionally, high stereo defect concentrations also lead to high xylene solubles content in the polymer which considerably narrows the resin manufacturing process window. [0005] There thus exists a long felt, but unmet need in the art for a BOPP grade resin that maintains the processability of the high xylene solubles homopolymer, but exhibits enhanced characteristics when processed into a BOPP film. SUMMARY OF THE INVENTION [0006] The present invention provides a polypropylene polymer suitable for use in producing BOPP film. The invention polymer comprises homopolymer polypropylene as well as a high ethylene content ethylene/propylene random copolymer. The invention polymer preferably comprises from about 70% to about 95% by weight of the homopolymer. In preferred embodiments, the homopolymer has less than 3% by weight xylene solubles and a crystallinity of at least 55%. The invention polymer further comprises about 5% to about 30% by weight of the ethylene/propylene random copolymer. Preferably, the ethylene/propylene random copolymer contains greater than about 7.2% to about 15% random ethylene by weight. [0007] The present invention also provides a method of manufacturing the invention polymer of the present invention. Preferably, the method of the invention comprises homopolymerizing propylene utilizing a Ziegler-Natta catalyst and one or more external donors. The method of preparing the invention polymer further comprises copolymerizing ethylene and propylene. [0008] The present invention likewise teaches a BOPP film comprising the resin of the present invention. The film may be either translucent, transparent, or opaque. [0009] In one embodiment, the invention is a resin composition comprising about 70% to about 95% by weight of a polypropylene homopolymer having less than 3% by weight xylene solubles and a crystallinity of at least 55%. The resin composition further includes about 5% to about 30% by weight of an ethylene/propylene random copolymer containing greater than about 7.2% to about 15% ethylene by weight. [0010] In a sub-embodiment, the polymer further comprises at least one additive selected from the group consisting of nucleators, antioxidants, acid neutralizers, slip agents, antiblock agents, antifogging agents, pigments, and combinations thereof. [0011] In another embodiment, the invention is a resin composition comprising about 70% to about 85% of a polypropylene homopolymer having less than 3% by weight xylene solubles and a crystallinity of at least 55%. The resin further includes about 15% to about 30% by weight of an ethylene/propylene random copolymer containing greater than about 7.2% to about 15% ethylene by weight. [0012] In a sub-embodiment, the polymer further comprises at least one additive selected from the group consisting of nucleators, antioxidants, acid neutralizers, slip agents, antiblock agents, antifogging agents, pigments, and combinations thereof. BRIEF DESCRIPTION OF THE FIGURES [0013] FIG. 1 depicts the process windows for polymers C, “75/25”, and FF029A. DETAILED DESCRIPTION OF THE INVENTION [0014] The polymer according to the current invention is a blend of high crystalline polypropylene homopolymer and a high ethylene content ethylene/propylene random copolymer. The blend may be produced either by melt blending or by an in-reactor process. [0015] Like high-xylene solubles BOPP film grade resin, the invention polymer fractionates into three components; an isotactic component; a stereoblock component, and an atactic component. Unlike high xylene solubles homopolymer, though, the isotactic component of the invention polymer is more crystalline. [0016] The stereoblock fraction of the invention polymer is likewise crystalline, but has a melting temperature lower than the stereoblock component of high xylene solubles BOPP grade resin. The combination of the higher crystallinity of the isotactic fraction and the lower melting temperature of the stereoblock fraction of the invention polymer as compared to standard BOPP grade homopolymer imparts enhanced physical properties to products comprising the resin while simultaneously maintaining the processability of the resin. Examples of enhanced properties in products comprising the resin include, but are not limited to, higher film tensile modulus. [0017] A further characteristic of the invention polymer is the random nature of ethylene dispersion throughout the random copolymer. In general, ethylene in a random copolymer of the present invention tends to be more random than not. For example, in one embodiment of a polymer of the present invention wherein the ethylene in the random copolymer is about 8 wt %, the number of triple and double ethylene insertions are each about 17 mol % in the invention polymer. Single insertions in this embodiment thus account for about 66 mol % of all ethylene in the invention polymer. Without wishing to be bound to any particular theory, it is believed that the high percentage of single ethylene insertions in the ethylene/propylene random copolymer contribute to the unique properties of the invention polymer. [0018] U.S. Pat. No. 5,460,884 to Kobylivker describes a composition comprising a homopolymer and an ethylene/propylene random block copolymer. The patent describes the random block copolymer as comprising 3% random ethylene and about 9% block ethylene, for a total of about 12% ethylene content. Although these values appear to fall within the range presently described, further analysis of the disclosure of the U.S. Pat. No. 5,460,884 patent, particularly the NMR spectrum included as FIG. 1 of that patent, shows that the ethylene/propylene block copolymer contains nearly 20% ethylene and is far blockier, i.e. contains more double and triple ethylene insertions, than it is random. [0019] The invention polymer may be prepared as a reactor blend, in which case copolymer is polymerized in the presence of the homopolymer. Alternatively, the homopolymer and copolymer may be produced separately and compounded (melt blended) after polymerization. The homopolymer as well as the copolymer may be produced in one or more gas, liquid, or slurry phase reactors. Preferably, the homopolymer is prepared in one or more loop (liquid) reactors and the copolymer is prepared in one or more gas phase reactors. When more than one reactor is used for a given polymerization, the additional reactor may be used in parallel or in series with the previous reactor. Preferably, when more than one reactor is used for a given polymerization, the reactors are in series. Although the applicants prefer loop and gas phase reactors for the described process, the use of other types of reactors for a given polymerization step is believed to be within the scope of the invention. [0020] The invention polymer preferably comprises about 70% to about 95% by weight of a polypropylene homopolymer. In one embodiment, the blend comprises from about 75% to about 90% propylene homopolymer. In another embodiment, the blend comprises from about 80% to about 95% homopolymer. [0021] In preferred embodiments, the polypropylene homopolymer has less than about 3% by weight xylene solubles as measured by ASTM 5492. In another embodiment, the xylene solubles are less than about 2%. In another alternative embodiment, the xylene solubles are less than about 1%. [0022] Preferably, the homopolymer has a crystallinity of at least about 55% as measured by Differential Scanning Calorimetry (“DSC”). Even more preferably the homopolymer has a crystallinity of at least about 57%. Most preferably, the homopolymer has a crystallinity of at least about 59% by DSC. DSC values are based on a total heat of fusion of 165 Joules/gram for 100% crystalline polypropylene according to B. Wunderlich, Macromolecular Physics, Volume 3, Crystal Melting, Academic Press, New York, 1980, pg. 63. [0023] The homopolymer of the invention is further characterized by a melting temperature of greater than about 155° C. More preferably, the homopolymer has a melting temperature of greater than about 160° C. Even more preferably, the homopolymer has a melting temperature of greater than about 162° C. Most preferably, the homopolymer has a melting temperature of greater than about 164° C. [0024] The pentad isotacticity of the xylene insoluble fraction of the homopolymer, as measured by 13 C NMR, is greater than at least about 95%. More preferably, the pentad isotacticity is greater than about 96%. Even more preferably, the pentad isotacticity of the xylene insoluble fraction is greater than about 97%. [0025] The invention polymer further comprises about 5% to about 30% by weight of a high ethylene content ethylene/propylene random copolymer. In one embodiment, the invention polymer comprises about 10% to about 25% copolymer. In another embodiment, the invention polymer comprises from about 15% to about 20% copolymer. [0026] Preferably, the ethylene content of the ethylene/propylene random copolymer is greater than about 7.2% to about 15% ethylene by weight. In certain embodiments, the copolymer may contain about 7.5% ethylene. In another embodiment, the copolymer may contain about 8% ethylene. In another embodiment, the copolymer may contain about 9% ethylene. In another embodiment, the copolymer may contain about 10% ethylene. In another embodiment, the copolymer may contain about 11% ethylene. In another embodiment, the copolymer may contain about 12% ethylene. In another embodiment, the copolymer may contain about 13% ethylene. In another embodiment, the copolymer may contain about 14% ethylene. In another embodiment, the copolymer may contain about 15% ethylene. [0027] The invention polymer may be produced with a melt flow rate (MFR) at any value in the range of from about 0.2 g/10 minutes to about 100 g/10 min. In preferred embodiments, the invention polymer preferably has a MFR of less than about 5 g/10 min, but more than about 1 g/10 min. More preferably the invention polymer MFR is less than about 4 g/10 min but more than about 1 g/10 min. The MFR of the invention polymer may, however, be less than about 3 g/10 min but more than about 1 g/10 min. [0028] For biaxially oriented (“BOPP”) films, the melt flow of the invention polymer is preferably from about 2 g/10 minutes to about 4 g/10 minutes. In another film application, the melt flow may be from about 4 g/10 minutes to about 6 g/10 minutes. In still another film application the melt flow may be from about 6 g/10 minutes to about 12 g/10 minutes. For injection molding or fiber spinning, the melt flow of the polymer is preferably about 12 g/10 minutes to about 100 g/10 minutes. [0029] The MFR of the invention polymer may be controlled through the addition or removal of hydrogen from a given polymerization process. Alternatively, or in conjunction with hydrogen MFR control, the desired MFR may be achieved through controlled rheology (visbreaking) via the addition of an appropriate amount of a suitable peroxide. [0030] The overall xylene solubles for the invention polymer are preferably less than about 4 weight %. More preferably, the xylene solubles of the invention polymer are less than about 3 weight %. Even more preferably, the xylene solubles are less than about 2 weight %. [0031] In certain embodiments, the overall ethylene content of the invention polymer is about 1.5 weight %. In other embodiments, the ethylene content of the invention polymer is about 1.2 weight %. In still other embodiments, the ethylene content of the invention polymer is about 0.9 weight %. In another embodiment, the ethylene content of the invention polymer is about 0.6 to about 0.7% by weight. [0032] The overall crystallinity of the invention polymer, as measured by DSC according to the procedure noted earlier herein, is greater than at least about 50%. More preferably, though, the crystallinity is greater than at least about 55%. In another embodiment, the crystallinity is greater than at least about 58%. In yet another embodiment, the crystallinity is greater than at least about 59%. [0033] The invention polymer melts at a temperature of greater than about 155° C. More preferably, the invention polymer has a melting temperature of greater than about 160° C. Even more preferably, the invention polymer has a melting temperature of greater than about 162° C. Most preferably, the invention polymer has a melting temperature of greater than about 164° C. [0034] The pentad isotacticity, as measured by 13 C NMR, of the xylene insoluble fraction of the invention polymer is preferably greater than about 94%. Even more preferably, the pentad isotacticity is greater than about 95%. [0035] The invention polymer may further comprise one or more additives selected from the group consisting of clarifiers, nucleators, acid scavengers (or neutralizers), antioxidants, slip or mold release agents, anti-static agents, antiblock agents, antifogging agents, pigments, and peroxide. These additives are typically introduced to the invention polymer during an extrusion/processing stage for both the in-reactor blended and melt blended materials. It is within the ability of the ordinarily skilled artisan to determine the appropriate amount of a given additive to be added to the invention polymer. [0036] The invention polymer may be prepared either via in-reactor blending or via melt blending. Preferably, the invention polymer is produced via in-reactor blending. [0037] In either a melt-blending or in-reactor blended process, homopolymer is preferably produced in one or more liquid phase loop reactors. Homopolymer may, however, be prepared in one or more slurry type reactors or in one or more gas phase reactors. When more than one reactor is used, the reactors are preferably in series. In all cases, homopolymer is produced using a Ziegler-Natta (ZN) catalyst system comprising titanium and an external electron donor. The homopolymerization reactor or reactors are preferably maintained at about 65° C. to about 80° C. throughout homopolymerization, most preferably at about 70° C. [0038] For preparation of an in-reactor blended invention polymer, the homopolymer produced in the one or more liquid phase reactors, along with the active catalyst from the homopolymerization, is passed to a gas phase reactor. [0039] In the gas phase reactor, ethylene and propylene are fed into the reactor to produce and maintain an atmosphere wherein ethylene is present in from about 2 to about 6 mole % based on the total number of moles of ethylene and propylene monomer present. Preferably, the ethylene content of the gas phase reactor is maintained at about 3 to about 4 mol % based on the total number of moles of ethylene and propylene monomer present. Most preferably, the ethylene content of the first gas phase reactor is maintained at about 3.5% based on the total number of moles of ethylene and propylene monomer present. The reactor is run at about 70° C. to about 100° C. Hydrogen is introduced into the reactor such that the molar ratio of hydrogen to ethylene is controlled to obtain the desired melt flow. [0040] After copolymerization, the resultant polymer mixture may be passed to a second gas phase reactor for a second copolymerization. In the second gas phase reactor, if used, ethylene and propylene are fed into the reactor to produce and maintain an atmosphere wherein ethylene is present in from about 2 to about 6 mole % based on the total number of moles of ethylene and propylene monomer present. Preferably, the ethylene content of the gas phase reactor is maintained at about 3 to about 4 mol % based on the total number of moles of ethylene and propylene monomer present and the reactor is run at about 90° C. to about 100° C. Hydrogen is introduced into the reactor such that the molar ratio of hydrogen to ethylene is controlled to obtain the desired melt flow. [0041] In the in-reactor process described above, the homopolymerization and copolymerization reactions are taught as each taking place in a series of reactors. It is, however, within the scope of this invention that homopolymerization takes place in one reactor, followed by copolymerization taking place in a second reactor such that only two reactors are used for the entire process. [0042] Once polymerization has concluded, the invention polymer is isolated from the reaction mixture for further processing. Specifically, and as noted previously, one or more of a number of additives may be added to the invention polymer in a compounding step. Subsequent to compounding, the invention polymer is pelletized and processed into a final product, such as a BOPP film. [0043] For preparation of a melt-blended invention polymer, homopolymer produced according to the procedure noted above is melt blended with random copolymer. Random copolymer is produced according to the procedure set forth above, except that no homopolymer is present in the copolymer reactor. As with the in-reactor blended variation, the melt blended invention polymer may be compounded with one or more different additives. Subsequent to melt blending and compounding, the invention polymer is pelletized and processed into a final product, such as a BOPP film. [0044] BOPP film prepared from the invention polymer typically exhibits processing characteristics nearly identical to those of standard BOPP grade resins. Unlike standard BOPP grade resins, though, a BOPP film prepared from the invention polymer exhibits unexpectedly enhanced physical properties. [0045] In a preferred embodiment, a BOPP film comprising the invention polymer exhibits a haze value of about 0.6%. The haze values of a film comprising the invention polymer may however, range from about 0.5% to about 2.0% such that the haze may be about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9%, about 1.0%, about 1.1%, about 1.2%, about 1.3%, about 1.4%, about 1.5%, about 1.6%, about 1.7%, about 1.8%, about 1.9%, or about 2.0% [0046] Preferably, the percent transmittance of the film is greater than about 90%. This value, however, may range from about 85% to about 100% such that the percent transmittance may be at least about 85%, about 86%, about 87%, about 88%, about 89%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, or at least about 99% depending upon the desired opacity or transparency. [0047] In a preferred embodiment, the BOPP film of the invention has a clarity of at least about 95%. This clarity value may, however, range from about 93% to about 99% such that the clarity of the BOPP film may be about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, or about 99%. Haze and clarity were measured using a BYK-Gardner Haze Gard Plus. [0048] Invention polymer that is optimized for production of clear or opaque films may be prepared by varying the tacticity of the propylene homopolymer component and the ethylene content of the random copolymer. Opaque films may also be produced by a process known as cavitating or cavitation. In cavitation, an organic or inorganic cavitating agent is dispersed within the invention polymer matrix prior to stretching. The presence of the cavitating agent in the matrix during stretching induces the formation of voids or cavities. After stretching the voids scatter light passing through the film, causing the film to appear opaque. Cavitation may occur in the absence of a cavitating agent, but is generally induced by the addition of a cavitating agent. Typical cavitating agents include, but are not limited to, polyethylene terephthalate, polybutylene terephthalate and calcium carbonate. [0049] In addition to the above, the BOPP film of the invention exhibits excellent mechanical properties. For example, a BOPP film of the invention preferably exhibits a TD modulus of greater than about 800,000 psi. In certain embodiments, the TD modulus is greater than about 825,000. In other embodiments, the TD modulus is greater than about 850,000 psi. Similarly, a BOPP film of the invention exhibits excellent MD modulus values. Preferably, the MD modulus of the film is greater than about 400,000 psi. In certain embodiments, the MD modulus may be greater than about 405,000 psi. In other embodiments, the MD modulus may be greater than about 410,000 psi. In other embodiments, the MD modulus may be greater than 425,000 psi. In still another embodiment, the MD modulus may be greater than about 450,000 psi. [0050] The BOPP films comprising the invention polymer of the invention may be prepared according to any known commercial process for producing films comprising standard BOPP grade resins. Two prevalent commercial processes include the tenter frame process and the “bubble” or blown film process. [0051] In a typical tenter frame process, molten polymer is supplied to a flat slot die, from which a cast sheet or film is extruded. This cast sheet or film is then conveyed to a chill roller where it is cooled to a suitable temperature. The cast sheet or film is then conveyed to a pre-heat roller where it is heated to an appropriate stretching temperature. [0052] Once at temperature, the cast sheet or film is subject to stretching. The cast sheet or film is first stretched in the “machine direction.” Stretching in the machine direction is performed by a pair of rollers, in series. The first roller spins at a speed one quarter to one eighth of the speed of the second roller. The speed differential between the two rollers causes a 4-8 fold stretching of the cast sheet or film when the cast sheet or film is passed through the roller sequence. [0053] After stretching in the machine direction, the film conveyed to an oven that heats the film to a temperature appropriate for stretching on a tenter frame disposed within the oven. Once the film is at temperature, the film is subject to stretching in the transverse direction, i.e. orthogonal to the machine direction. The film is stretched when a plurality of tenter clips are attached to opposite sides of the film and a force is applied to the clips. Once stretched, the film may be annealed. [0054] In the bubble or blown film process, the typical steps include extruding molten polymer through an annular die. The extrudate is then rapidly cooled in water to form a calibrated tube. The tube is then conveyed to an orientation tower where one end of the tube is squeezed with a first stretching nip to produce an airtight seal. The partially sealed tube is then heated and inflated with high-pressure air to form a large diameter bubble. The bubble orients the film in the transverse direction. Simultaneously, the bubble is stretched in the machine direction. The oriented bubble is then collapsed by one or more converging rolls. After being collapsed, the BOPP film is annealed and cut into two webs. Finally, each web is corona or flame treated and wound for storage. [0055] Those skilled in the art will recognize that these examples of a tenter frame and bubble process are for illustrative purposes only. Variations of either process are within the knowledge of one skilled in the art and are considered to be within the scope of the present invention. Moreover, films produced using the invention polymer of the invention are not limited to those produced by either the tenter frame or bubble process. EXAMPLES [0056] Two batches of invention polymer (an in-reactor blend) were prepared using the parameters, P1 and P2, set forth in Table 1. For each polymerization, high crystalline homopolymer, H, was prepared in two liquid phase loop reactors (LR×1 and LR×2 in Table 1) in series using a Ziegler-Natta catalyst and an external donor. Homopolymer and the active catalyst were then fed into a first gas phase reactor (Gas-Phase Reactor 1) for copolymerization. Upon completion the reaction mixture was transferred to a second gas phase reactor (Gas-Phase Reactor 2) for a subsequent copolymerization. [0000] TABLE 1 P1 P2 Loop Reactor 1 (LRx1) and 2 (LRx2) Temperature of LRx1 & LRx2 (° C.) 70 70 LRx1 H2 (ppm) 993 1049 LRx1 C3 feed rate (T/hr) 33.25 34.91 LRx2 H2 concentration (ppm) 876 902 LRx2 C3 feed rate (T/hr) 12.15 12.41 Gas-Phase Reactor 1 Temperature (° C.) 90 90 Pressure (kg/cm 2 ) 11.8 11.8 C2/(C2 + C3) (mole ratio) 0.035 0.034 H2/C2 (mole ratio) 0.046 0.050 C2 feed (kg/hr) 168 172 C3 feed (T/hr) 1.58 1.65 C2 (mole %) 3.17 3.1 C3 (mole %) 86.43 86.49 Gas-Phase Reactor 2 Temperature (° C.) 100 100 Pressure (kg/cm 2 ) 11.4 12.0 C2/(C2 + C3) (mole ratio) 0.033 0.038 H2/C2 (mole ratio) 0.063 0.038 C2 feed (kg/hr) 105 109 C3 feed (T/hr) 1.31 1.43 C2 (mole %) 3 2.92 C3 (mole %) 90.6 89.5 [0057] Two samples of homopolymer H, H1 and H2, produced according to parameters P1 and P2, respectively, were analyzed prior to copolymerization. The properties of the homopolymers are shown in Table 2. Table 2 also shows the properties of the invention polymers B1 and B2 that resulted after the second copolymerization. [0000] TABLE 2 H1 H2 B1 B2 MFR N/A N/A 2.2 2.1 Xylene solubles (wt. %) N/A N/A 1.72 1.63 C2 content in invention polymer N/A N/A 0.64 0.67 (wt. %)* C2 content in random copolymer N/A N/A 7.98 7.76 (wt. %)** Random Copolymer content of N/A N/A 8.02 8.75 Invention Polymer (wt. %)*** Mn/1000 (Xylene Insolubles) N/A N/A 65.9 59.5 Mn/1000 (Xylene Solubles) N/A N/A 16.8 14.4 Mw/1000 (Xylene Insolubles) N/A N/A 291 284 Mw/1000 (Xylene Solubles) N/A N/A 96 98 MWD (Xylene Insolubles) N/A N/A 4.42 4.77 MWD (Xylene Solubles) N/A N/A 5.7 6.8 Mz/1000 (Xylene Insolubles) N/A N/A 1063 992 Mz/1000 (Xylene Solubles) N/A N/A 340 377 % X c 61.0 59.5 57.7 56.6 T m (° C.) 165.3 164.9 164.0 164.1 T c (° C.) 114.8 113.5 112.7 112.9 Pentad isotacticity of XI (%)* 96.80 97.08 95.41 95.36 *By 13 C NMR **From a mass balance of the manufacturing process. ***From mass balance calculation using C2 content in polymer and C2 content in copolymer. [0058] Samples B1 and B2 were subsequently mixed and compound with an additives package to give compounded material, C. Material C was then compared to two other resins: 1) a melt blended compound comprising 75% C and 25% H (“75/25”); and 2) Sunoco polymer FF029A, a BOPP grade resin. The properties of C, 75/25, and FF029A are shown in Table 3. [0000] TABLE 3 Property C 75/25 FF029A MFR 2.5   2.6 2.9 % XS 2.76   2.3 4.1 Mn/1000 67.1  68.1* 65.2 Mw/1000 313  321* 334 Mz/1000 1509 1428* 1228 MWD 4.7   5.2 5.1 T m (° C.) 165.3  166.2 162.3 T c (° C.) 119  120.2 112.1 % X c 59.0  60.5 55.3 *Calculated value. [0059] For further comparison, compounds C, 75/25, and FF029A were each extruded and formed into cast sheets approximately 24 mils thick and 11″ wide. In this process, the extruded polymer melt was quenched onto a chill roll maintained at 70° F. The cast sheets were then further processed into film having a width of 60″ and an exit thickness of approximately 0.0007″ using a draw ratio of 5.0×8.0 (MD×TD). Complete processing conditions are shown in Table 4. [0000] TABLE 4 Extrusion and Tenter Line Processing Conditions C 75/25 FF029A Melt Temp 490 492 491 Extruder Zone 1 450 450 450 Temperatures Zone 2 480 480 480 (F.) Zone 3 480 480 480 Zone 4 480 480 480 Die Temp 480 480 480 Screw RPM  55  60  61 Chill Roll Temp (F.)  70  70  70 Cast Line FPM    15.48    15.44    15.54 Cast Sheet 24 Mils 24 Mils 24 Mils Thickness Cast Sheet Width   11″   11″   11″ MDO Stretch Ratio  5  5  5 MDO Roll (F.) Preheat 1 250 250 250 Preheat 2 250 250 250 Slow Draw 250 250 250 Fast Draw 229 229 229 Anneal 1 219 219 219 Cooling 120 120 120 TDO Stetch Ratio  8  8  8 TDO OVEN (F.) Oven Zone 1 328 334 330 Oven Zone 2 326 334 328 Oven Zone 3 320 330 320 TDO Exit     0.0007″     0.0007″     0.0007″ Thickness TDO Exit Width   60″   60″   60″ [0060] Table 5 shows the physical properties of the resulting films. Tensile modulus values were generated at the products' ideal processing temperature. Ideal processing temperatures are considered to be the center of a product's process window wherein the low end of the process window is determined by web breaks and the high end of the process window is determined by high haze. The processing windows for C, 75/25, and FF029A are shown in FIG. 1 . [0000] TABLE 5 Physical Properties C 75/25 FF029A Ideal Process 328 F. 332 F. 325 F. Temperature Film thickness 0.00061 0.00069 0.00068 (inches) Haze (%) 0.57 0.63 0.84 Transmittance (%) 94.08 94.13 94.05 Clarity (%) 98.93 98.65 98.88 TD Modulus (psi) 845,000 870,000 770,000 MD Modulus (psi) 410,000 445,000 401,000 [0061] These examples demonstrate that the invention polymer is ready substitute for standard BOPP grade resin, providing enhanced performance in the form of improved strength in both MD and TD moduli, without sacrificing processability. [0062] The present invention has thus been described in general terms with reference to specific examples. Those skilled in the art will recognize that the invention is not limited to the specific embodiments disclosed in the examples. Those skilled in the art will understand the full scope of the invention from the appended claims. [0063] All references contained herein are hereby incorporated by referenced in their entirety.
A polypropylene resin, useful for the production of biaxially oriented polypropylene (BOPP) film, is provided. The polymer of the present invention is a blend of high crystalline polypropylene homopolymer and a high ethylene ethylene/propylene random copolymer (RCP). The present invention also provides a method of preparing the novel resin as well as a novel BOPP film comprising the resin.
2
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims any and all benefits as provided by law of U.S. Provisional Application No. 60/889,033 filed Feb. 9, 2007, which is hereby incorporated by reference in its entirety. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH [0002] Not Applicable REFERENCE TO MICROFICHE APPENDIX [0003] Not Applicable BACKGROUND [0004] Global positioning system (GPS) receivers are widely used and have many potential applications. Many electronic devices now include GPS receivers such as mobile phones, in-car navigation systems, and vehicular-guidance systems. An electronic device containing a GPS receiver is capable of precisely determining the location (plus or minus a few centimeters) of the electronic device, anywhere in the world. Generally, using a GPS device, a user is able to obtain position information in terms of latitude, longitude, and altitude. The position information can then be processed into other forms of information, such as a location on a map or a Postal Code. [0005] GPS receivers can use signals from a combination of satellite-based transmitters and ground-based transmitters to calculate the receiver's position. Referring to FIG. 1 , orbiting the Earth is a constellation of twenty-four satellites (A, B, C, D, E, F) in six planes. Each of the satellites transmits signals modulated by a pseudo-random noise (PRN) code towards the Earth's surface. A unique PRN code (also known as a “gold code”) is assigned to each GPS satellite, with several spare PRN codes available. The signals can carry information that includes a coarse/acquisition code, a precision code (P-code), and a navigation message. GPS receivers calculate location information using the signals and information from at least three of the GPS satellites. By comparing the amount of time that it took for the signal transmitted by each satellite to reach the GPS receiver, and using the data contained in the signals, the GPS receiver is able to precisely calculate the location of the GPS receiver. The ground-based transmitters can monitor the GPS signals, and correct for any drift in the orbits of the GPS satellites by updating the ephemeris constant and/or the base clock offset of each of these satellites. In this manner, a user can use a GPS receiver to precisely determine the location of the GPS receiver. [0006] The GPS satellites transmit signals over several frequencies such as the L1 carrier frequency (1575.42 MHz) and the L2 carrier frequency (1227.6 MHz), and in the future, the L5 carrier frequency (1176.45 MHz). The GPS satellites use Direct Sequence Spread Spectrum (DSSS) modulation, which is a type of code-division multiple-access (CDMA) modulation, to modulate the signals transmitted by each of the GPS satellites. The signals transmitted by each of the GPS satellites (e.g., the P-code, the coarse/acquisition signal, etc.) are “spread” by the PRN code corresponding to an individual satellite. The spread signal is used to modulate a carrier frequency (e.g., the L1 and/or L2 frequencies). The modulated spread signal is broadcast to GPS receivers. The use of DSSS can increase the signal's resistance to interference. Since each signal is nearly uncorrelated with respect to each other, the DSSS modulated GPS signals can be demodulated using standard CDMA techniques. [0007] The navigation message is a 50 Hz signal that includes data bits describing the GPS satellite orbits, clock corrections, and other system parameters. A complete navigation message is sent over the course of a 12.5-minute cycle using twenty-five 1500-bit frames. A single 1500-bit frame is sent every thirty seconds (yielding an effective throughput of 50 bps). Each 1500-bit frame is divided into five 300-bit sub-frames. The first sub-frame of each 1500-bit frame includes satellite-specific clock-correction information. The second and third sub-frames include satellite-specific ephemeris data information. The fourth and fifth sub-frames include system data, or almanac data. Combining twenty-five consecutive corresponding sub-frames (e.g., twenty-five consecutive fourth sub-frames, twenty-five consecutive fifth sub-frames, etc.) yields an entire navigation message. [0008] The signals transmitted by the GPS satellites travel line of sight, but can have a hard time passing through solid objects such as building structures and mountains. For example, if a user has a GPS receiver inside of a 50-story building, the user may not be able to receive any GPS satellite signals. The lack of a GPS satellite signal can have disastrous consequences such as an inability for 911 call centers to locate a caller or an inability to communicate with an object and/or a vehicle, such as an automated or guided vehicle, en-route to a destination. [0009] The Federal Communications Commission (FCC) has established a wireless Enhanced 911 (“E911”) plan. The E911 program is divided into two parts—Phase I and Phase II. Phase I requires wireless carriers to report the telephone number of a wireless 911 caller and the location of the carrier's antenna that received the call. Phase II of the E911 regulations require wireless carriers to provide far more precise location information, within 50 to 300 meters in most cases. To comply with the wireless E911 plan, many wireless carriers have integrated GPS receivers into mobile phones, and other mobile communication devices. In the event of a 911 call by a mobile phone user, the GPS enabled mobile phone can relay location information provided by the GPS receiver to a 911 call center for use in determining the location of the mobile phone. SUMMARY [0010] Various aspects of the invention can provide one or more of the following capabilities. Virtually any type of information can be transmitted to GPS receivers using the existing GPS infrastructure. Information can be transmitted to GPS receivers (e.g., a device with an antenna, a radio receiver that can receive GPS signals and information, and a processor for use the worldwide GPS system) using the navigation message of a GPS signal. Information can be transmitted to GPS receivers using a terrestrial GPS transmitter such as a pseudolite (e.g., a terrestrial transmitter that can provide services typically provided by a satellite such as a GPS signal), a mobile transmitter, an airborne transmitter, a satellite or existing GPS satellites. Communication with and reprogramming of electronic devices coupled to a GPS receiver can be accomplished. GPS containing devices, vehicles and ordnances can be reprogrammed or redirected using information received in a GPS signal. By using the GPS receiver to sent information to these GPS containing devices, vehicles and ordnances, the space, weight and cost of providing a separate receiver for this information can be avoided. [0011] Standard GPS receivers can continue to operate successfully even in the presence of information signals containing supplemental information. A transmission source can utilize signal PRN codes which are unused either in the entire GPS satellite constellation or at least with respect to the “visible” satellites at the time of the transmission. Information can be addressed to a specific GPS receiver. Information can be provided to an electronic device having no communication capability apart from an attached GPS receiver device, without redesigning the electronic device. Information can be provided to a GPS receiver using a non-interfering duty-cycle, for example, a duty cycle that is less than about 30% of existing GPS satellite transmissions. Information can be provided to a GPS receiver by modulating the information using an orthogonal code different from any of the GPS satellites. Existing GPS receivers and attached electronic devices can be reprogrammed using information transmitted in a GPS signal. Information such as, system control information or course-correction information can be transmitted to vehicular guidance systems and ordnances. Information can be transmitted to mobile and aerial vehicles and devices. Covert communication can be accomplished. [0012] These and other capabilities of the invention, along with the invention itself, will be more fully understood after a review of the following figures, detailed description, and claims. BRIEF DESCRIPTION OF THE DRAWINGS [0013] FIG. 1 is a schematic diagram of a constellation of GPS satellites. [0014] FIG. 2 is a schematic diagram of a GPS system including terrestrial transmitters. [0015] FIG. 3 is a schematic diagram of a portion of a navigation message included in a GPS signal. [0016] FIG. 4 is a flowchart of a process for transmitting and receiving information using the system shown in FIG. 2 . [0017] FIG. 5 is a flowchart of a process for transmitting and receiving information using the system shown in FIG. 2 . [0018] FIG. 6 is a schematic diagram of an implementation of a GPS system using terrestrial transmitters. [0019] FIG. 7 is a flowchart of a process for transmitting information to a guide vehicle. [0020] FIG. 8 is a schematic diagram of a waveform related to the principal of orthogonality. DETAILED DESCRIPTION [0021] Embodiments of the invention provide techniques for transmitting information, such as data, to a GPS receiver device without substantially interfering with standard GPS satellite signals. GPS receiver devices include electronic devices with the capability to receive GPS satellite signals, such as GPS-enabled mobile phones, in-vehicle navigation systems, vehicular guidance systems, aviation navigation systems, maritime navigation systems, etc. A transmission source transmits information to a GPS receiver using GPS-like signals. The information can be transmitted to a GPS receiver, for example, using signals with a lower (or complementary) duty-cycle than existing GPS signals and/or by modulating the signal using available PRN codes (for example, one of the spare or unused PRN codes). Depending on the chosen transmission method, the GPS receiver can use CDMA demodulation techniques to demodulate and extract the information contained in the GPS-like signals broadcast to the GPS receiver. [0022] Referring to FIG. 2 a GPS system 15 includes the GPS satellites 20 , 30 , and 40 , transmitters 50 , 60 , 70 , and 80 , signals 22 , 32 , 42 , 52 , 62 , 72 , and 82 , a land/stationary platform 90 , a mobile platform 95 , an airborne platform 100 and a GPS receiver 105 . The satellites 20 , 30 , and 40 transmit the GPS signals 22 , 32 , and 42 towards Earth 115 for reception by the GPS receiver 105 . Supplemental “GPS-like” signals, such as signals 52 , 62 , 72 , and 82 , can be used to broadcast GPS information and/or other information to GPS receivers. Other quantities and configurations of the transmitters 50 , 60 , 70 , and 80 , the satellites 20 , 30 , and 40 , and/or the GPS receiver 105 are possible (e.g., five satellites, one ground-based transmitter, and four GPS receivers). [0023] The transmitters 50 , 60 , 70 , and 80 can be used to provide GPS signals and/or GPS-like signals to the GPS receiver 105 . Non-satellite transmitters can be stationary, mobile, airborne, and/or terrestrial. For example, the transmitter 50 is installed on the land/stationary platform 90 , the transmitter 60 is installed within a building 120 , and the transmitter 70 is installed on the mobile platform 95 (in FIG. 2 , a truck). The land platform 90 can be a stationary object such as a pole dedicated to the transmitter 50 or another structure such as a radio antenna, a mobile-phone tower, a light pole, a roof of a building, a water tower, a bridge, a mountain top, etc. The mobile platform 95 can be a moving object, such as a car, a truck, a boat, a train, a bus, a tank, etc. The transmitter 80 is installed on an airplane 100 , although other similar aerial vehicles can be used (e.g., a helicopter, an unmanned aerial vehicle (UAV), satellite and/or a blimp). [0024] Non-satellite based transmitters (e.g., the transmitters 50 , 60 , 70 , and 80 ) can be used to supplement (e.g., repeat) the GPS signals transmitted by the GPS satellites, and/or to send GPS-like signals including information to the GPS receiver 105 . The type of information that can be broadcast to the GPS receiver 105 (or any GPS enabled device) is broad. The information can be non-GPS information which does not include information that is not intended to be used by the GPS for determining the position of the GPS receiver and can be used by the GPS receiver (or a device connected to the GPS receiver) for related or unrelated purposes. For example, the information can include information such as location information, text messages, image files, audio data or files, video data or files, reconfiguration instructions, firmware upgrades, encrypted signals, software updates, anti-virus updates, Web pages, navigation information, navigation files, e-mails, map files, document files, etc. The information can include covert communications that are encrypted or otherwise hidden, such as using steganographic methods. The information can also include information of significance to vehicular or ordnance guidance or control systems such as speed, direction destination information and updates, coordinate information and updates, operational instructions and updates, etc. Transmissions of other types of information are possible. [0025] Information can be sent to a GPS receiver 105 using standard GPS signal formats such as the navigation message embedded in the GPS signals 22 , 32 , 42 , 52 , 62 , 72 , and 82 . The navigation message can be replaced with other information, which can result in a bandwidth of approximately 50 bits-per-second (bps). Other data rates are possible. Other portions of a standard GPS signal can be replaced with other information. More than one of the unused PRN codes can be used to transmit data. [0026] Referring also to FIG. 3 , a navigation message 400 includes frames 405 and sub-frames 410 1 through 410 5 . Twenty-five of the frames 405 make up a single navigation message 400 , although other quantities of frames 405 can make up an entire navigation message 400 (e.g., 50 of the frames 405 can make up a single navigation message 400 ). Each of the frames 405 includes five sub-frames 410 1 through 410 5 , although other quantities of sub-frames 410 can make up a single one of the frames 405 (e.g., ten sub-frames can make up a single one of the frames 405 ). [0027] The information can be a single 50 bit payload which is sent in a single one of the sub-frames 410 , or can be a larger message that is split up over multiple sub-frames 410 or multiple navigation messages sent on the same or multiple PRN codes. For example, a 2000-bit message can be split up over forty consecutive sub-frames 410 . The 2000-bit message could be split up over forty consecutive corresponding sub-frames (e.g., forty consecutive 410 2 sub-frames). Other combinations are possible. The GPS receiver can reconstruct information that has been split up over multiple sub-frames, or alternatively a processor located externally from the GPS receiver can reconstruct information split up over multiple sub-frames 410 . [0028] The information transmitted by the non-satellite based transmitters can be broadcast using existing GPS frequencies such as the L1 and L2 bands, and in the future, the L5 band, although other frequency bands can be used. Because the GPS satellites can transmit on the same frequency bands as the transmitters 50 , 60 , 70 , and 80 , the signals transmitted by the transmitters 50 , 60 , 70 , and 80 can interfere with existing GPS signals. To reduce, or even eliminate interference, information can be broadcast to GPS receivers (e.g., the GPS receiver 105 ) using an available PRN code to encode the information and/or using different or lower duty-cycle transmissions. Varying the duty-cycle of the transmissions (e.g., using a duty cycle of 10-30%) can reduce interference with existing GPS signals by improving the signal-to-noise ratio of the information transmitted relative to existing GPS signals. Other techniques can be used. [0029] In operation, referring to FIG. 4 , with further reference to FIG. 2 , a process 200 for transmitting information using an available PRN code and the GPS system 15 includes the stages shown. The process 200 , however, is exemplary only and not limiting. The process 200 can be altered, e.g., by having stages added, removed, or rearranged. [0030] At stage 205 an available PRN code is identified. An available PRN code is a PRN code such as one of the spare PRN codes and/or a PRN code in use by a GPS satellite 5 that is out of view of the GPS receiver 105 . If one of the spare PRN codes is chosen, the likelihood of interference with another of the GPS satellites can be reduced or even eliminated. Alternatively, a tracking module (e.g., a computer processor running the necessary software) can track the GPS satellites to determine which of the satellites are “in-view” of the GPS receiver 105 at any given time. The tracking module can select a PRN code corresponding to one of the GPS satellites that is not in-view of the GPS receiver 105 to modulate the information being broadcast by the transmitters 50 , 60 , 70 , and/or 80 . As the GPS satellites orbit the Earth 115 , the availability of a particular PRN code can change. For example, in FIG. 2 , the GPS satellite 30 (here, acting as one of the GPS satellites) is shown in-view of the GPS receiver 105 making its code unavailable for use in the DSSS modulation process. As the satellite 30 orbits the Earth 115 , the satellite 30 can disappear over a horizon of the Earth 115 , which can make its PRN code available for use by a ground based transmitter. Once the satellite 30 is again in-view of the GPS receiver, however, its PRN code becomes unavailable. The tracking module can track and/or predict which PRN code will be available at any given time. [0031] At stage 210 , the information can be sent using DSSS and the selected available PRN code. Portions of the information can be sent using one or more of the available PRN codes. For example, multiple information streams can be sent using different PRN codes, or a single information stream can be split into multiple streams that are sent using different PRN codes. [0032] At stage 215 , the sent information can be amplified and broadcast by a transmitter (e.g., the satellites 20 , 30 , and/or 40 , and/or the transmitters 50 , 60 , 70 , and/or 80 ) for reception by a GPS receiver (e.g., the GPS receiver 105 ). When the GPS satellites are used to broadcast non-GPS signals, cooperation by the entity operating the satellite (e.g., the United States Government) may be required. [0033] At stage 220 , the sent information can be received and amplified by a GPS receiver (e.g., the GPS receiver 105 ). The transmitted information can be demodulated to substantially recover the sent information. Error correction, such as a cyclic redundancy check (CRC) code with error correction capability, can be used during transmission process. At stage 225 the recovered information is output by the GPS receiver. [0034] The stages 220 and/or 225 (including sub-portions of the stages 220 and/or 225 ) can be accomplished by a GPS receiver (e.g., the GPS receiver 105 ), or another device external to the GPS receiver. For example, the GPS receiver 105 itself can demodulate the received modulated information. Alternatively, the GPS receiver 105 (for example, a GPS receiver in a mobile device) can receive the information stream and retransmit it via a wired or wireless network to a remote processor, such as one operated by mobile phone network operator. The remote processor can then demodulate the sent information and transmit the recovered information to the GPS receiver 105 and/or the attached mobile device. [0035] In operation, referring to FIG. 5 , with further reference to FIG. 2 , a process 300 for transmitting information using reduced duty-cycles and/or non-interfering duty-cycles, or PRN codes, using the GPS system 15 includes the stages shown. The process 300 , however, is exemplary only and not limiting. The process 300 can be altered, e.g., by having stages added, removed, or rearranged. While the process 300 describes the process of transmitting information, the process 300 can also be used to transmit standard GPS signals. [0036] At stage 305 , a transmitter (e.g., the satellites 20 , 30 , and/or 40 , and/or the transmitters 50 , 60 , 70 , and/or 80 ) broadcasts the information stream using a duty cycle of about 10-30%. Other duty cycles can be used. The information stream is a modified navigation message, as described above, although other forms of the information stream are possible. Broadcasting information using a lower duty cycle than standard GPS signals can reduce, or possibly eliminate interference with standard GPS signals. The information stream is encoded using an existing PRN code. The PRN code used to encode the information stream can be a PRN code in-use by a GPS satellite for transmitting GPS signals, although unused PRN codes can be used in addition to or instead of the in-use PRN code. The encoded information stream can be broadcast at a power level higher than existing GPS signals, subject to saturation effects in the GPS transmitter and/or receiver. [0037] At stage 310 , a GPS receiver (e.g., the GPS receiver 105 ) receives the lower duty-cycle broadcast. The GPS receiver can be configured to detect, receive, and/or process the lower duty-cycle broadcast to recover the information contained therein. For example, correlation and integration can be used to recover the lower duty-cycle broadcast when the signal strength is below the noise floor. The GPS receiver processes the lower-duty cycle information stream such that simultaneous detection of existing GPS signals is possible. At stage 315 , the GPS receiver outputs the recovered information using standard GPS spread spectrum processing (as described herein). [0038] The stages 310 and/or 315 can be accomplished by a GPS receiver (e.g., the GPS receiver 105 ), or another device external to the GPS receiver. For example, the GPS receiver 105 can be configured to process the lower duty-cycle broadcast to recover the information. Alternatively, the GPS receiver can receive the lower-duty cycle broadcast and retransmit it to a remote processor using, for example, wired, cellular or other wireless transmission technology. The remote processor can process the received broadcast to recover the information, and transmit the recovered information to the GPS receiver 105 and/or the attached mobile device. [0039] The GPS system 15 of FIG. 2 can be used to provide information to GPS receivers (here, the GPS receiver 105 ). When the GPS receiver is able to receive standard GPS signals, the GPS system 15 can be used to augment the standard GPS signals by providing information to the GPS receiver 105 . Alternatively, in locations where the GPS receiver 105 is unable to receive standard GPS signals (e.g., within a building or a cave), the GPS system 15 can be used to relay the standard GPS signals and/or provide other information to the GPS receiver 105 . [0040] The information can be used to communicate with GPS enabled guided vehicles or ordnances. For example, some guided vehicles and ordnances can receive GPS signals such as a Global Positioning System Aided Munition (GAM). Because some GPS enabled guided vehicles are programmed with target coordinates prior to being launched, it can be desirable to be able to transmit information (e.g., updated target or destination coordinates, abort, or other control information) to the guided vehicle or ordnance after being launched while the guided vehicle is en route to a target. [0041] Referring to FIG. 6 a targeting system 700 includes a satellite 705 , a guided vehicle (or ordnance) 710 , a transmitter 715 , a launch site 720 , and a command center 725 . The satellite 705 can be one of the GPS satellites, or can be another space vehicle such as the satellites 20 , 30 , and/or 40 , a military satellite, a commercial satellite, a space vehicle, etc. The GPS enabled guided vehicle 710 can be launched from the launch site 720 towards a target or destination 730 by the command center 725 . If the target 730 is a mobile target (e.g., a tank, a ship, etc.) that is in motion while the guided vehicle 710 is in flight, updated or new target (or destination) coordinates can be transmitted by the command center 725 to the guided vehicle 710 using the transmitter 715 and/or the satellite 705 . If the target 730 changes, for example a new target is selected, while the guided vehicle 710 is in flight, updated or new target (or destination) coordinates can be transmitted by the command center 725 to the guided vehicle 710 using the transmitter 715 and/or the satellite 705 . In addition or alternatively, other information, such as control information, can be transmitted to the guided vehicle 710 , for example, changes in speed or direct and abort, return to base or self-destruct instructions. The command center 725 can monitor the target 730 using various methods such as radar (not shown), ground based operatives (not shown), etc. [0042] In operation, referring to FIG. 7 , with further reference to FIG. 6 , a process 800 for transmitting information to a guided vehicle, using the targeting system 700 includes the stages shown. The process 800 , however, is exemplary only and not limiting. The process 800 can be altered, e.g., by having stages added, removed, or rearranged. [0043] At stage 805 the guided vehicle is programmed with coordinates of a target. The coordinates can be, for example, information that represents the latitude and longitude of the target, although other location or guidance information can be used. At stage 810 , the guided vehicle 710 is launched. [0044] At stage 815 , the command center 725 determines whether the guided vehicle 710 is still in flight. If the guided vehicle 710 is no longer in flight, the process 800 ends. If the guided vehicle 710 is still in flight, the process 800 continues. [0045] At stage 820 , the location of the target 730 is monitored by, for example, the command center 725 using radar. At stage 825 , the command center 725 determines if the target has moved (or the destination has changed) from the targeting (or destination) coordinates programmed into the guided vehicle 710 in stage 805 . If the targeting information does not require updating, the process 800 returns to stage 815 . If the targeting information requires updating, at stage 830 the targeting system 700 transmits updated targeting (or destination) coordinates encoded in GPS-like signals to the guided vehicle 710 via the satellite 705 and/or the transmitter 715 using for example, the process 200 (of FIG. 4 ) and/or the process 300 (of FIG. 5 ). Alternatively, the targeting system 700 can transmit control information that changes the direction and/or speed of the guided vehicle 710 to control time of arrival and destination of the guided vehicle 710 . [0046] While communication with GPS enabled guided vehicles has been disclosed, other applications and types of communications are possible. For example, GPS-like signals can be used to transmit information to unmanned aerial vehicles, military aircraft, ground stations, individual troops, etc. [0047] Other embodiments are within the scope of the invention. For example, due to the nature of software, functions described above can be implemented using software, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions can also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. [0048] While FIG. 1 has been described in context of a single GPS receiver (i.e., the GPS receiver 105 ), other quantities are possible. The GPS satellites 20 , 30 , and 40 can be configured to transmit other information. The GPS receivers 105 can require upgrades/updates to use the method and systems described herein, such as software updates, firmware updates, hardware updates, etc. The PRN codes used to modulate the information can be totally orthogonal, or partially orthogonal. When two carrier frequencies are totally orthogonal to one another, the frequencies are chosen such that a receiver can reject an unwanted interfering signal, regardless of the intensity of the interfering signal. For example, when multiple modulation frequencies are used, each frequency overlaps with surrounding frequencies. When the signals are orthogonal, however, the points at which a desired frequency is measured, all other frequencies are zero (e.g., arrow 900 in FIG. 8 ). The L1 band and/or the L5 band is preferably used for “life-critical” information (e.g., navigation information provided to a commercial airliner), although other frequency bands can be used. While some signals have been described as “GPS-like,” other formats are possible. For example, the navigation message format of a standard GPS signal can be replaced by another message format. [0049] Further, while the description above refers to the invention, the description may include more than one invention.
A system for transmitting non-GPS information for reception by a global positioning system (GPS) receiver, the system including a processor, a memory coupled to the processor and including computer-readable instructions configured to, when executed by the processor, cause the processor to receive the non-GPS information, determine an available pseudo-random noise (PRN) code, spread the non-GPS information using the available PRN code to provide a spread signal, modulate a GPS carrier frequency using the spread signal to produce a GPS compatible signal, and a terrestrial transmitter configured to transmit the GPS compatible signal.
6
BACKGROUND OF THE INVENTION (1) Field of the Invention The present invention relates to a thin carbon plate and a process for producing the same. More particularly, the present invention relates to a thin carbon plate excellent in properties such as gas impermeability, mechanical strengths and the like, as well as to a process for producing the same. (2) Prior Art Carbon materials have properties not possessed by other materials, such as excellent heat resistance, chemical stability, light-weight and the like. Therefore, they have been used as a special electrode agent, various jigs, a sealing agent, a separator for a fuel cell, etc. and moreover are finding wider usages. Various additional requirements for higher performances have recently become necessary for carbon materials having excellent properties as mentioned above. That is, there has become necessary a thin carbon plate excellent in gas impermeability, mechanical strengths, etc. Conventional thin carbon plates have been obtained by impregnating a high-density graphite with a phenolic resin, or binding a carbon powder with a resin, or carbonizing a phenolic or furan resin, or adding a graphite powder or a carbon fiber to a phenolic or furan resin and carbonizing the resulting mixture. These conventional thin carbon plates, however, have low mechanical strengths or low gas impermeability when made into a thin plate. SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems of the prior art and provide a thin carbon plate having sufficient mechanical strengths and gas impermeability and a process for producing the same. That is, in order to solve the above problems of the prior art, the present inventors made study with particular attention paid to a polycarbodiimide resin which can be easily molded into a thin plate and which can give a carbonization product of high carbon content at a high yield and, as a result, completed the present invention. According to the present invention, there is provided a process for producing a thin carbon plate, which comprises molding a polycarbodiimide resin into a thin plate, subjecting the thin plate to a heat treatment, and carbonizing the heat-treated thin plate. The present invention also provides a thin carbon plate obtained by molding a polycarbodiimide resin into a thin plate, subjecting the thin plate to a heat treatment, and carbonizing the heat-treated thin plate. DETAILED DESCRIPTION OF THE INVENTION The present invention is hereinafter described in detail. The polycarbodiimide resin used in the present invention can be a known polycarbodiimide resin or a polycarbodiimide resin which can be produced in the same manner as for known polycarbodiimide resin [reference is made to U.S. Pat. No. 2,941,966; Japanese Patent Publication No.33297/1972; J. Org. Chem., 28. 2069.2075 (1963); Chemical Review, 1981, Vol. 81, No. 4, 619-621; etc.]. It can be easily produced by subjecting an organic diisocyanate to a condensation reaction wherein the elimination of carbon dioxide takes place. The organic diisocyanate used in the production of a polycarbodiimide resin can be any of aliphatic type, ali cyclic type, aromatic type, aromatic-aliphatic type, etc. They can be used alone or in combination of two or more (the latter case gives a copolymer). The polycarbodiimide resin used in the process of the present invention includes a homopolymer or a copolymer both having at least one repeating unit represented by the formula --R--N═C═N-- (I) wherein R represents an organic diisocyanate residue. As the R (organic diisocyanate residue) in the formula (I), there are particularly preferred an aromatic diiso. cyanate residue [In the present specification, the "organic diisocyanate residue" refers to a portion remaining after subtracting two isocyanate (NCO) groups from an organic diisocyanate molecule.]. The polycarbodiimidization catalyst has no particular restriction and can be illustrated by conventionally used phosphorene oxides such as 1-phenyl-2-phosphorene-1-oxide, 3-methyl-2-phosphorene-1-oxide, 1-ethlyl-3-methyl-2-phosphorene -1-oxide, 1-ethyl-2-phosphorene-1-oxide and 3-phosphorene isomers thereof or the like. Specific examples of the polycarbodiimide resin include the following. ##STR1## In the above formulas, n is a degree of polymerization and is in the range of 10-10,000, preferably in the range of 50-5,000. Incidentally, the terminal(s) of the polycarbodiimide resin may be blocked with a monoisocyanate or the like, and the polycarbodiimide resin described above can be obtained in a solution form, or as a powder precipitated from the solution. The thus obtained polycarbodiimide resin is molded into a thin plate. The molding into a thin plate is effected, for example, as follows. The reaction mixture itself after synthesis of polycarbodiimide resin, or a polycarbodiimide resin solution obtained by isolating a polycarbodiimide resin powder from said reaction mixture and dissolving the powder in a solvent, is cast on, for example, a flat smooth glass plate, and then the solvent in the reaction mixture or the solution is removed. As the solvent, there can be used tetrachloroethylene, trichloroethylene, tetrahydrofuran, dioxane, monochlorobenzene, dichlorobenzene, dimethylformamide, N-methyl-2-pyrrolidone, dimethylacetamide, dimethylsulfoxide, etc. It is possible that a polycarbodiimide resin powder be subjected to compression molding, roll molding, injection molding, transfer molding or the like to obtain a thin plate. By these molding methods, a thin plate having a thickness of about 0.1-3 mm can be obtained easily. The thin plate is then subjected to a heat treatment. This heat treatment is effected at temperatures of 150°- 400° C., preferably 200-350° C. for 30 minutes to 50 hours. The heat treatment increases moldability and yield in a subsequent carbonization step and also improves dynamic properties after carbonization. The above heat treatment can be effected in an oxidizing atmosphere such as air or the like. Lastly, the heat-treated thin plate is carbonized. Carbonization is effected by elevating the temperature of the thin plate from around room temperature -200° C. to 600°-3,000° C. in vacuum or a non-oxidizing atmosphere of inert gas. The temperature elevation is preferably effected slowly at a rate of preferably 30° C./min or less. The temperature elevation to 600° C. or more gives a final thin plate having substantially desired properties. When the final carbonization temperature is less than 600° C., the resulting thin plate has low electrical conductance and, when the temperature is more than 3,000° C., the thin plate has a low yield. In the above carbonization, as soon as the temperature elevation has reached the final temperature, the thin plate has substantially desired properties; accordingly, it is not necessary to continue carbonization at the final temperature. It is of course possible to effect the heat treatment step and the carbonization step continuously by subjecting a polycarbodiimide resin thin plate to a heat treatment at the above-mentioned temperatures for the above-mentioned period and successively carbonizing the heat-treated thin plate under the above-mentioned conditions. The present invention is hereinafter described in more detail by way of Examples. EXAMPLE 1 54 g of a 80:20 mixture of 2,4-tolylenediisocyanate and 2,6-tolylenediisocyanate [TDI] was reacted in the presence of 0.12 g of a carbodiimidization catalyst (1-phenyl -3-methylphosphorene oxide) in 500 ml of tetrachloroethylene at 120° C. for 4 hours to obtain a polycarbodiimide solution. From the solution was prepared a polycarbodiimide thin plate of 200 μm in thickness by a dry method. The thin plate was subjected to a heat treatment by elevating the temperature from 150° C. to 300° C. at a rate of 1° C./min. The heat treated thin plate was carbonized by elevating the temperature in an inert gas current from room temperature to 1,000° C. at a rate of 10° C./min. Immediately, the carbonized thin plate was allowed to cool to room temperature to obtain a thin carbon plate of 180 μm in thickness. The properties of the thin carbon plate obtained are shown in the Table given later. EXAMPLE 2 50 g of methylenediphenyl diisocyanate [MDI] was reacted in the presence of 0.13 g of a carbodiimidization catalyst (1-phenyl-3-methylphosphorene oxide) in 880 ml of tetrahydrofuran at 68° C. for 12 hours to obtain a polycarbodiimide solution. The solution was developed on a glass plate and a dry method was applied to obtain a polycarbodiimide thin plate of 200 μm in thickness. The thin plate was subjected to a heat treatment by elevating the temperature from 150° C. to 250° C. at a rate of 1° C./min and keeping the plate at 250° C. for 3 hours. The heat-treated thin plate was heated from room temperature to 1,000° C. at a rate of 10° C./min in an inert gas current and then immediately allowed to cool to obtain a thin carbon plate of 180 μm in thickness. The properties of the thin carbon plate obtained are shown in the Table given later. EXAMPLE 3 The polycarbodiimide thin plate obtained in Example 1 was heated from 150° C. to 350° C. at a rate of 2° C./min and then carbonized in the same manner as in Example 1 to obtain a thin carbon plate. The properties of the thin carbon plate obtained are shown in the Table given later. EXAMPLE 4 50 g of paraphenylene diisocyanate was reacted in the presence of 0.13 g of a carbodiimidization catalyst (1-phenyl-3-methylphosphorene oxide) in 880 ml of tetrahydrofuran at 68° C. for 5 hours. The resulting solution was cooled to room temperature, whereby a polycarbodiimide was precipitated. The precipitate was collected by filtration and dried at 100° C. for 2 hours to obtain a polycarbodiimide powder. The powder was subjected to press molding at a press temperature of 180° C. at a press pressure of 80 kg/cm 2 to prepare a polycarbodiimide thin plate of 500 μm in thickness. The thin plate was subjected to a stepwise heat treatment by heating it at 150° C. for 2 hours, at 200° C. for 5 hours, at 250° C. for 2 hours and at 350° C. for 30 minutes. The heat-treated thin plate was heated from room temperature to 1,000° C. at a rate of 5° C./min in nitrogen, and immediately allowed to cool to obtain a thin carbon plate of 420 μm in thickness. The properties of the thin carbon plate obtained are shown in the Table given later. EXAMPLE 5 150 g of MDI was reacted in the presence of 0.13 g of a carbodiimidization catalyst (1.phenyl.3.methylphosphorene oxide) in 820 ml of tetrachloroethylene at 120° C. for 6 hours, and the same manner as in Example 4 was applied to obtain a polycarbodiimide powder. This powder was subjected to press molding at a press temperature of 160° C. at a press pressure of 80 kg/cm 2 to prepare a polycarbodiimide thin plate of 500 μm in thickness. This thin plate was subjected to a heat treatment in the same manner as in Example 1. The heat-treated thin plate was heated from room temperature to 1,000° C. at a rate of 5° C./min in nitrogen to obtain a thin carbon plate of 420 μm in thickness. The properties of the thin carbon plate obtained are shown in the Table given later. EXAMPLE 6 The polycarbodiimide thin plate prepared in Example 1 was subjected to a heat treatment by elevating the temperature from 150° C. to 300° C. at a rate of 2° C./min. The heat-treated thin plate was carbonized by elevating the temperature from room temperature to 2,000° C. at a rate of 10° C./min in an inert gas current, and then immediately allowed to cool to room temperature to obtain a thin carbon plate of 175 μm in thickness. The properties of the thin carbon plate obtained are shown in the Table given later. COMPARATIVE EXAMPLE 1 The properties of GC COMPOSITE (separator for a fuel cell, a commercial product of Kobe Steel, Ltd.) of 1 mm in thickness are shown in the Table given later. COMPARATIVE EXAMPLE 2 The polycarbodiimide thin plate prepared in Example 1 was heated from 150° C. to 430° C. at a rate of 2° C./min. In this heat treatment, the thin plate caused pyrolysis and had no handleability, making subsequent carbonization impossible. COMPARATIVE EXAMPLE 3 The polycarbodiimide thin plate of 500 μm in thickness, prepared in Example 5 was carbonized by elevating the temperature from room temperature to 1,000° C. at a rate of 5° C./min in nitrogen, without subjecting the thin plate to a heat treatment, whereby a thin carbon plate of 420 μm was obtained. The properties of the thin carbon plate obtained are shown in the Table given later. TABLE______________________________________ Bulk Gas imperme- Specific Tensile density ability resistance strength g/cm.sup.3 cc/min · cm.sup.3 mΩ · cm kg/mm.sup.2______________________________________Example 1 1.71 9.2 × 10.sup.-7 3.0 28Example 2 1.71 1.0 × 10.sup.-6 2.9 27Example 3 1.71 2.0 × 10.sup.-7 3.0 28Example 4 1.71 9.0 × 10.sup.-7 2.9 27Example 5 1.71 5.0 × 10.sup.-7 3.2 25Example 6 1.71 9.5 × 10.sup.-7 3.1 26Comparative 1.71 2.0 × 10.sup.-5 3.3 4.25Example 1Comparative ← Unable to measure →Example 2Comparative 1.70 1.2 × 10.sup.-6 19Example 3______________________________________
The present invention relates to a thin carbon plate and a process for producing the same. More particularly, the present invention relates to a thin carbon plate excellent in properties such as gas impermeability, mechanical strengths and the like, as well as to a process for producing the same.
2
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application for patent claims priority from and the benefit of provisional application Ser. No. 61/054,410 entitled “DC PASS BROADBAND RF PROTECTOR,” filed on May 19, 2008, which is expressly incorporated herein by reference. BACKGROUND [0002] 1. Field [0003] The invention relates to surge protection. More particularly, the invention relates to a surge protection device for passing DC and RF signals. [0004] 2. Related Art [0005] Surge protection devices protect electronic equipment from being damaged by large variations in the current and voltage across power and transmission lines resulting from lightning strikes, switching surges, transients, noise, incorrect connections, and other abnormal conditions or malfunctions. Large variations in the power and transmission line currents and voltages can change the operating frequency range of the electronic equipment and can severely damage and/or destroy the electronic equipment. For example, lightning is a complex electromagnetic energy source having potentials estimated from 5 million to 20 million volts and currents reaching thousands of amperes that can severely damage and/or destroy the electronic equipment. [0006] Surge protection devices typically found in the art and used in protecting electronic equipment include capacitors, diodes, gas tubes, inductors, and metal oxide varistors. A capacitor blocks the flow of direct current (DC) and permits the flow of alternating current (AC) depending on the capacitor's capacitance and the current frequency. At certain frequencies, the capacitor might attenuate the AC signal. For example, the larger the capacitance value, the greater the attenuation. Typically, the capacitor is placed in-line with the power or transmission line to block the dc signal and undesirable surge transients. [0007] Gas tubes contain hermetically sealed electrodes, which ionize gas during use. When the gas is ionized, the gas tube becomes conductive and the breakdown voltage is lowered. The breakdown voltage varies and is dependent upon the rise time of the surge. Therefore, depending on the surge, several microseconds may elapse before the gas tube becomes ionized, thus resulting in the leading portion of the surge passing to the capacitor. Gas tubes are attached at one end to the power or transmission line and at another end to the ground plane, diverting the surge current to ground. [0008] Inductors can be attached to the power or transmission line after the gas tube and before the capacitor to divert the leading portion of the surge to ground. An inductor is a device having one or more windings of a conductive material, around a core of air or a ferromagnetic material, for introducing inductance into an electric circuit. An inductor opposes changes in current, whereas a capacitor opposes changes in voltage. [0009] One drawback of conventional surge protection devices is the difficulty in impedance matching the surge protection device with the system. Another drawback of conventional surge protection devices is the elevated voltage at which they become conductive and the higher throughput energy levels. Still yet another drawback of conventional surge protection devices is poor bandwidth capabilities and poor RF performance at high power levels. SUMMARY [0010] A surge protection circuit to reduce capacitance inherent of standard diode packaging and to improve voltage clamping reaction speeds under high surge conditions. The surge protection circuit has a coil having a first end and a second end and a diode cell having a top layer, a center diode junction, and a bottom layer. The top layer is directly connected to the second end of the coil and the bottom layer is directly connected to a ground. The diode cell has no wire leads. [0011] A surge protection device comprising a housing, a cavity defined by the housing, first and second connector pins positioned within the cavity, and a loop foil positioned within the cavity, the loop foil having a first end connected to the first connector pin and a second end connected to the second connector pin. The surge protection device may also include a coil positioned within the cavity, the coil having a first end connected to the first connector pin and a second end, and a diode cell connected to the housing, the diode cell having a top layer, a center diode junction, and a bottom layer, the top layer directly connected to the second end of the coil and the bottom layer directly connected to the housing. [0012] A surge protection device having a housing, a cavity defined by the housing, a diode positioned within the cavity, and first and second connector pins positioned within the cavity. The surge protection device may also include a loop foil positioned within the cavity, the loop foil having a first plate connected to the first connector pin, a second plate connected to the second connector pin, and a third curved plate connecting the first plate to the second plate, and an inductor positioned within the cavity, the inductor having a first end connected to the first connector pin and a second end connected to the diode. BRIEF DESCRIPTION OF THE DRAWINGS [0013] The features, objects, and advantages of the invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, wherein: [0014] FIG. 1 is a schematic diagram of a surge protection circuit according to an embodiment of the invention; [0015] FIGS. 2A-2D are schematic diagrams showing different diode and capacitor configurations that can be implemented with the surge protection circuit of FIG. 1 according to various embodiments of the invention; [0016] FIG. 3 is a top view of a surge protection device having the surge protection circuit of FIG. 1 according to an embodiment of the invention; [0017] FIG. 4 is a side view of the surge protection device of FIG. 3 according to an embodiment of the invention; [0018] FIG. 5 is a perspective view of a diode of the surge protection device of FIG. 4 according to an embodiment of the invention; [0019] FIG. 6 is a top view of a diode of the surge protection device of FIG. 4 according to an embodiment of the invention; [0020] FIG. 7 is a side view of a diode of the surge protection device of FIG. 4 according to an embodiment of the invention; [0021] FIG. 8 is a side view of a loop foil according to an embodiment of the invention; [0022] FIG. 9 is a top view of a loop foil according to an embodiment of the invention; [0023] FIG. 10 is a front view of a loop foil according to an embodiment of the invention; [0024] FIG. 11 is a side view of a loop foil according to another embodiment of the invention; [0025] FIG. 12 is a top view of a loop foil according to another embodiment of the invention; [0026] FIG. 13 is a front view of a loop foil according to another embodiment of the invention; and [0027] FIG. 14 shows a graph of the average RF power handling capabilities of a number of different connectors according to various embodiments of the invention. DETAILED DESCRIPTION [0028] Apparatus, systems and methods that implement the embodiments of the various features of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate some embodiments of the invention and not to limit the scope of the invention. Throughout the drawings, reference numbers are re-used to indicate correspondence between referenced elements. In addition, the first digit of each reference number indicates the figure in which the element first appears. [0029] FIG. 1 is a schematic diagram of a surge protection circuit 100 according to an embodiment of the invention. The surge protection circuit 100 may include a first port 105 , a second port 110 , a loop foil 115 , a coil 120 , a diode 125 , and a ground 130 . Optionally, the surge protection circuit 100 may include a capacitor 135 . The surge protection circuit 100 provides improved RF coupling between the first port 105 and the second port 110 , improved voltage clamping using the coil 120 and the diode 125 , improved surge current performance by the diode 125 , improved RF performance and grounding at higher RF power levels (e.g., greater than 750 Watts), and greater bandwidth capabilities. The surge protection circuit 100 may operate in a bi-directional manner. [0030] The first connector or port 105 and the second connector or port 110 may include center connector pins 106 and 111 of a coaxial cable or line. The first port 105 and the second port 110 maintain the system RF impedance between the device and the connected termination (e.g., 50 ohm, 75 ohm, etc.). The first connector 105 and the second connector 110 may be selected from one of the following connectors: 7/16 connector, N-Type connector, BNC connector, TNC connector, SMA connector, and SMB connector. The first connector 105 and the second connector 110 may be press-fit connectors, flange-mount connectors, or any other type of connectors. [0031] FIG. 14 shows a graph of the average RF power handling capabilities of a number of different connectors. The combined RF plus DC power handling capabilities of the surge protection device 100 are generally limited by the type of connectors used. In one embodiment, the first connector 105 may be a N-type connector and the second connector 110 may be a SMA connector. In this example, the RF power handling capabilities may be limited to approximately 350 Watts (i.e., the power handling capabilities of the SMA connector). [0032] Referring back to FIG. 1 , the loop foil 115 allows DC currents and RF signals to pass from the first port 105 to the second port 110 and vice versa. The loop foil 115 is a curved copper foil material formed in the shape of a “U” or backwards “U”. The loop foil 115 is a single integral piece of copper material but for illustrative purposes, the loop foil 115 will be referred to as having a first plate 115 a , a second plate 115 b , and a third curved plate 115 c . The copper material of the loop foil 115 is about 0.016 inches in thickness. In one embodiment, the first plate 115 a is positioned about 0.2 inches apart from the second plate 115 b . The first plate 115 a is positioned substantially parallel to the second plate 115 b . The third curved plate 115 c connects the first plate 115 a to the second plate 115 b. [0033] The inductance, the mutual impedance, and the positioning of the loop foil 115 within the cavity 310 is used for impedance matching to compensate for internal RF mis-match impedances of the coil 120 , the diode 125 , and the cavity 310 . The capacitance of the device can be increased by positioning the loop foil 115 closer to the walls of the cavity 310 . The inductance of the device can be increased by using a thinner material for the loop foil 115 . The mutual impedance of the device can be increased by moving the first plate 115 a and the second plate 115 b closer together. By increasing the inductance and the mutual impedance of the loop foil 115 , the size and number of turns required in the coil 120 can be reduced resulting in further simplification of design and cost. [0034] The coil 120 may be an inductor having one or more loops. The coil 120 has a first end 120 a directly attached to the center connector pin 106 and a second end 120 b directly attached to the diode 125 . The coil 120 may have a 14AWG, 16AWG, 18AWG, or larger AWG. In one embodiment, the coil 120 has an inductance of about 0.5 uH. The coil 120 isolates the diode 125 from the RF transmission path. Also, the coil 120 adds isolation between the center connector pins and the diode 125 to achieve better passive intermodulation (PIM) performance compared to that of the diode 125 without isolation. When a surge event occurs (or a high DC surge voltage), the coil 120 effectively becomes a short circuit and the diode 125 operates to pass the surge event. [0035] The diode 125 is connected to the coil 120 and the ground 130 . That is, a first end of the diode 125 is connected to the coil 120 and a second end of the diode 125 is connected to the ground 130 . The diode 125 can be oriented for a positive polarity or negative polarity DC clamping. In addition, the diodes 125 can be stacked to obtain higher voltage clamping while maintaining the equivalent current carrying capabilities. [0036] The capacitor 135 is positioned in parallel with the diode 125 . In one embodiment, the capacitor 135 has a capacitance of about 1,000 pF or higher. The capacitor 135 allows the energy to be shunted to ground 130 and prevents the diode 125 from prematurely being turned on. The size of the capacitor 135 is dependent on the frequency of operation and generally allows for broadband applications. The capacitor 135 provides better RF grounding for the surge protection circuit 100 at higher power levels. The surge path generally includes the coil 120 , the diode 125 , and the capacitor 135 . [0037] FIGS. 2A-2D are schematic diagrams showing different diode and capacitor configurations that can be implemented with the surge protection circuit of FIG. 1 according to various embodiments of the invention. The capacitor 135 may or may not be implemented in the surge protection circuit 100 . The diodes 125 have superior voltage clamping characteristics. FIG. 2A shows a uni-directional diode, FIG. 2B shows a bi-directional diode, FIG. 2C shows multiple uni-directional diodes stacked in a series configuration, and FIG. 2D shows a uni-directional diode. [0038] In one embodiment, the diode 125 can be a low voltage, bi-directional diode that is capable of handling 10 kA 8×20 micro-second surge currents with excellent voltage let-thru characteristics. In one embodiment, the diode 125 can be a bi-directional, high current transient voltage suppressor (TVS) diode having a breakdown voltage of between about 5.0-150.0 volts (e.g., 6, 12, 18 or 24 volts) and a high peak pulse power rating (e.g., 5,000, 20,000 or 30,000 watts). By isolating the diode 125 from the RF transmission path using the coil 120 , the negative RF affects (e.g., capacitance) of the diode 125 are mitigated. The high frequency (RF) isolation characteristics of the coil 120 increases the impedance looking into the coil 120 and the diode 125 but the low frequency (DC and surge) components have a low impedance path to the diode 125 . [0039] FIGS. 3 and 4 are top and side views of a surge protection device 300 having the surge protection circuit of FIG. 1 according to an embodiment of the invention. Referring to FIGS. 3 and 4 , the surge protection device 300 has a housing 305 and a cavity 310 defined by the housing 305 . The cavity 310 may be formed in the shape of a circle (as shown), oval, ellipse, square, and rectangle. The loop foil 115 is positioned within the cavity 310 . The loop foil 115 does not come into direct contact with the housing 305 but rather is connected between the center connector pins 106 and 111 . The coil 120 is also positioned within the cavity 310 and is connected to the center connector pin 106 and the diode 125 . In one embodiment, the diode 125 is connected to a base plate 315 or a base of the cavity 310 . [0040] The surge protection device 300 has various frequency characteristic bands within the range of approximately 300 Hz to 5 GHz. Return losses of greater than or equal to 20 dB and insertion losses of less than or equal to 0.1 dB, for example, are from approximately 700 MHz to 2,400 MHz. A return loss of greater than 50 dB may be realized within a narrow band, for example, between approximately 1,400 MHz and 1,600 MHz. [0041] FIGS. 5 , 6 and 7 are perspective, top and side views of a diode of the surge protection device of FIG. 4 according to an embodiment of the invention. In one embodiment, the diode 125 may be a diode cell 500 having three layers 505 , 510 , and 515 . The center diode junction or layer 510 may be sandwiched between top and bottom metal layers 505 and 515 . The diode cell 500 does not have any wire leads, thus reducing the inductance and improving voltage clamping under high surge conditions. The second end 120 b of the coil 120 is directly attached to the top metal layer 505 of the diode cell 500 . The bottom metal layer 515 of the diode cell 500 is directly attached to the ground 130 . No wire leads are used to connect the diode cell 500 to the coil 120 or the ground 130 . [0042] In one embodiment, the diode cell 500 may have a length L 1 of about 9.40 mm, a width W 1 of about 9.40 mm, and a thickness T 1 of about 1.29 mm. The diode 125 may be two or more diodes in parallel circuit configuration. The diode cell 500 may include a hole 520 for mounting to the housing 305 . If the hole 520 is not present, the diode cell 500 may be mounted or soldered to the base plate 315 to facilitate grounding of the diode 125 to the housing 305 . [0043] FIGS. 8 , 9 and 10 are side, top and front views of a loop foil 115 according to an embodiment of the invention. In this embodiment, H 2 is about 15.875 mm, L 2 is about 22.36 mm, W 2 is about 8.89 mm, and T 2 is about 0.41 mm. The loop foil 115 is symmetrical when the end connectors are the same. That is, L 3 and L 4 have the same length of about 11.18 mm. [0044] FIGS. 11 , 12 and 13 are side, top and front views of a loop foil 115 according to another embodiment of the invention. In this embodiment, H 2 is about 15.875 mm, L 2 is about 22.36 mm, W 2 is about 8.89 mm, and T 2 is about 0.41 mm. Since one connector is a SMA connector and one connector is a N-Type connector, L 3 and L 4 have different lengths. That is, L 3 is about 11.53 mm and L 4 is about 10.06 mm. Each series of connectors (N or SMA, etc.) are manufactured for a fixed impedance (e.g., 50 Ohms) generally to the formula for coaxial lines which is a relationship including pin diameter, connector shell inside diameter and the supporting medium dielectric coefficient. The physical size of the two connectors is obviously different while maintaining the same impedance. Because of this physical difference, L 3 and L 4 must vary to impedance match to the cavity. There is actually some difference when using connectors of the same series but different gender, because actual center pin length varies. The variance is less dramatic than that of non similar series connectors in which case L 3 and L 4 generally are the same. [0045] The previous description of the disclosed examples is provided to enable any person of ordinary skill in the art to make or use the disclosed methods and apparatus. Various modifications to these examples will be readily apparent to those skilled in the art, and the principles defined herein may be applied to other examples without departing from the spirit or scope of the disclosed method and apparatus. The described embodiments are to be considered in all respects only as illustrative and not restrictive and the scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
A surge protection circuit to reduce capacitance inherent of standard diode packaging and to improve voltage clamping reaction speeds under high surge conditions. The surge protection circuit has a coil having a first end and a second end and a diode cell having a top layer, a center diode junction, and a bottom layer. The top layer is directly connected to the second end of the coil and the bottom layer is directly connected to a ground. The diode cell has no wire leads.
7
FIELD OF THE INVENTION The present invention relates generally to hybrid backmounted child carriers/push strollers. In particular, the present invention is concerned with a wheeled retrofit system releasably attachable to an existing back-mounted child carrier. BACKGROUND OF THE INVENTION Presently, there are a variety of back mounted child carriers available on the market such as those designed and sold by TOUGH TRAVELER®. Such carriers utilize a shoulder harness that allows an adult to carry an infant or small child on the adult's back. These back mounted child carriers typically are constructed from aluminum tubular framing and nylon materials for seating and padding. Such designs are particularly advantageous when the adult is hiking or traveling on a terrain where a carriage or stroller is not a practical solution for transporting an infant or young child. However, even given the relative comfort and ease of use of the child carriers, there may be times when it is desirable to remove the child and the carrier from the adult's back and stroll the child rather than carry the child. Thus, hybrid carrier/stroller devices which can function as both have recently been made available. Presently, there exist several vendors, such as EVENFLO® who provide combination child carrier/child stroller contraptions. Unfortunately, these vendors only provide units that are all-in-one designs. This is not always an ideal solution since many users, who use such devices primarily as carriers, may find it undesirable to have to deal with the added weight and bulkiness of a carrier bogged down with additional components such as wheels and a handlebar. In other words, many users may not want to be locked into a hybrid design. In addition, for those users who presently have an existing child carrier, purchasing an entirely new piece of equipment to serve both purposes is more costly. Until now, no device has existed which can be mounted to an existing child carrier to maintain the convenient features of a light weight child carrier while also providing a child stroller device. Nor do any vendors provide a releasably mountable retrofit system which can be easily attached and removed from an existing child carrier as required by the user. The present invention seeks to provide this functionality. SUMMARY OF THE INVENTION Briefly, the present invention provides a simple retrofit attachment system that allows a back mounted child carrier to be converted into a hybrid child carrier/stroller without sacrificing any of the advantages of the child carrier. The present invention comprises a handlebar apparatus and a wheel unit, both of which can be releasably mounted to the tubular framing of an existing child carrier. The handlebar apparatus and wheel unit are designed such that they can be easily attached and removed as needed by the user. More particularly, the handlebar apparatus may be designed such that it can telescope up to provide a suitable height when strolling the infant and telescope down when carrying the infant. Additionally, the wheel unit may be designed such that it can collapse thereby providing an even more compact design when the system is used as a back-mounted child carrier and not as stroller. Finally, the wheel unit and the handlebar apparatus may include a single mounting bracket capable of connecting both devices easily to the existing child carrier. Such a unit increases the ease by which both the handlebar apparatus and wheel unit may be attached. Another advantage of the present invention is a detachable wheel unit having curvilinear tubular supports for providing increased structural integrity. The curvilinear shape allows for supporting greater loads. In accordance with the above, it is an object of the present invention to provide a retrofit device that will allow a child carrier to be converted into a hybrid carrier/stroller. In accordance with the above, it is a further object of the present invention to provide a releasably attachable retrofit system. BRIEF DESCRIPTION OF THE DRAWINGS These and other advantages of the present invention will become more readily apparent upon reading the following detailed description and upon reference to the drawings to which: FIG. 1 is a side view of a typical existing child carrier; FIG. 2 is a rear view of a portion of the frame of an existing child carrier; FIG. 3 is a rear view of a portion of the frame of an existing child carrier with a retrofitted wheel unit and handlebar mounted thereon; FIG. 4 is a side view of an existing child carrier with a retrofitted wheel unit and handlebar apparatus mounted thereon; FIG. 5 is a side view showing an alternate embodiment of the wheel unit; FIG. 6 is a rear view of a portion of the frame of an existing child carrier showing an alternate embodiment of the retrofitted wheel and handlebar apparatus mounted thereon; FIG. 7 is a side view of the present invention with a saddle bag mounted thereon; FIG. 8 depicts a first alternate embodiment for a collapsible wheel unit pursuant to the present invention; FIG. 9 depicts the collapsible wheel unit of FIG. 8 in the collapsed position; FIG. 10 depicts a three-holed clamp used to mount the present invention onto an existing child carrier; FIG. 11 depicts a second alternate embodiment for a collapsible wheel unit design pursuant to the present invention; and FIG. 12 depicts a third alternate embodiment for a collapsible wheel unit design pursuant to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and more particularly to FIG. 1, there is shown a side view of a typical back-mounted child carrying device 10 as manufactured by TOUGH TRAVELER®. The carrier utilizes a system of tubular framing 12, 14 and 16, various straps and nylon padding, and a shoulder harness 19. The child sits in the carrier 10 facing forward (i.e., facing towards the shoulder harness). The tubular framing generally consists of three pieces, a forward support frame member 16, a rear support frame member 12, and a frame stand member 14. FIG. 2 depicts a rear view of the rear support frame member 12 and part of the forward support frame member 16. FIG. 3 depicts the same view as FIG. 2 with the retrofit system attached thereto pursuant to this invention. In particular, this includes the attachment of handlebar apparatus 25, wheel unit 31, and protective tab 38. Handlebar apparatus 25 is mounted to the rear support frame member 12 using handlebar mounting devices 22. The handle mounting device may incorporate a clamp, bolt, quick release system, screw device and/or any known means that will allow for easy attachment and removal. In addition, the handlebar mounting devices 22 may be adapted for mounting the handlebar unit 25 at various angles with respect to the frame member 12 (e.g., through the use of a swivel mounting). The handlebar unit 25 may incorporate an extendable handlebar system thus allowing the height of the push bar 23 to be adjusted. The method shown incorporates upper telescoping vertical supports 28 which can slide up and down within the lower fixed supports 20. The upper support 28 can be easily locked into place by using a locking device 26. This device may utilize a peg, cotter pin, spring loaded pin mechanism, screw, wing nut or any readily available known means. While this figure depicts one type of an adjustable handlebar system, it is not meant to be exclusive. Any other known type, including an extendable, collapsible, foldable, retractable or telescoping handlebar apparatus could also be used. Handlebar apparatus 25 may also comprise a grip 24 to fit over push bar 23. The grip may be made from rubber, plastic, tape or any other suitable material which will allow for improved gripping. Wheel unit 31 is mounted to rear support frame member 12 using mounting devices 32. These devices are similar to the handlebar mounting devices 22. Note that an alternate embodiment may be implemented which provides a combination mounting device to attach both the handlebar apparatus and the wheel unit to rear support frame member 12 (see FIGS. 4 & 10). The wheel unit 31 may include a support bar 30, wheel frames 40, wheels 34, an axle 36, and attachment devices 42. Any known wheel unit configuration which is light weight and readily mountable could also be used, including any of the known baby stroller/carriage art which presently exists. For instance, wheels 34 could incorporate any of the swivel type wheels frequently used in the art. In addition, wheel unit 31 could incorporate springs in the design to act as shock absorbers. This embodiment may also incorporate a feature whereby the wheels 34 and some portion of the wheel unit may be readily separated and removed from the remaining wheel unit. For instance, attachment devices 42 may be designed such that wheel frames 40 can attach and release, slide in and out, or be clamped and unclamped from support bar 30. Thus, an alternate method of wheel attachment and removal is provided. Finally, protective tab 38 is attachable to the bottom portion 18 of forward support frame member 16. This provides protection against wear and tear caused when that portion of forward support member 16 (or the carrier fabric or straps connected thereto) comes in contact with the ground. The protective tab may be made from any protective material such as rubber, plastic or fabric. FIG. 4 depicts a side view of a child carrier with the retrofit apparatus attached in accordance with the present invention. As shown, the wheeled carrier has affixed thereto handlebar apparatus 25, wheel unit 31 and protective tab 38. As shown in this embodiment, a single mounting device 33 is incorporated which attaches one side of both the wheel unit 31 and the handlebar apparatus 25 to rear frame support member 12. (Note that a total of two clamps, one for each side, is required). This single clamp design allows for easier attachment and removal. FIG. 10 depicts a three hole clamp suitable for this purpose. A first hole 62 clamps onto a wheel frame member, a second hole 64 clamps onto rear frame support member 12, and a third hole 66 clamps onto handlebar apparatus 25. The retrofit system, in accordance with FIG. 4, is operational as both a back-mounted child carrier and a stroller. To use it as a stroller, one simply pulls back on the push bar 23 such that the entire weight is transferred onto wheels 34. The unit may then be effortlessly strolled. Note that in the resting position, the weight is distributed between wheels 34 and protective tab 38. In addition, note that frame stand member 14 (see FIG. 1) is not shown. It may either be disconnected or folded forward while the retrofit unit is attached. FIG. 5 depicts a side view of a child carrier with the attached retrofit unit incorporating an alternative wheel design. In this embodiment, a forward and a rear set of wheels, 43 and 45 respectively, are utilized within an alternate wheel unit design 41. This system provides for greater stability. This system may also incorporate wheels that lock so that the stroller is not free to roll when unattended. FIG. 6 depicts a rear view of the rear frame support member with an alternative handlebar apparatus 46 design attached thereto. The handlebar apparatus as shown utilizes a single vertical support member 48 with push bar 50 attached thereto. This design may also provide an adjustable push bar height. This may be accomplished via the use of a telescoping vertical section 52 that slides up and down within the vertical support member 48. (It may also incorporate any of the extension methods described above with regard to FIG. 3). This design may be attached to the child carrier using brackets 53. FIG. 7 depicts a side view of a child carrier with attached retrofit system pursuant to this invention and further incorporating side saddle bags 54. In addition to providing additional storage, the saddle bags may be designed to provide protection to the child's feet while being strolled. FIGS. 8 and 9 depict a collapsible wheel system which can be incorporated into the wheel unit. As shown in FIG. 8 (top view), the wheels 56 can be collapsed inwardly when the child carrier is not being used as a stroller. In this embodiment, axle 36 of FIG. 3 is removed. To improve strength, a four wheel design (as shown) may be incorporated. FIG. 9 (rear view) depicts the wheels as fully collapsed. FIG. 11 depicts a top view of a second type of collapsible wheel frame unit 70. The unit comprises a pair of wheels 72, each mounted in its own wheel frame member 74. Each individual wheel frame member 74 may be mounted to the child carrier with clamps 76. The clamps 76 may be designed to clamp around rear frame support member 12 (see FIG. 1). The clamps 76 may be fastened via a quick release mechanism, bolts, wing nuts, or the like. Foldable bar 78 is connected interiorly to each wheel frame member 74. Foldable bar 78 comprises at least one locking hinge device 80. Locking hinge device 80 provides wheel unit 70 with the ability to collapse when the unit 70 is removed from the child carrier. When collapsed, the unit can be more easily stored or carried. Locking hinge device 80 may also incorporate a locking feature such that when the unit 70 is attached to a child carrier the hinge is locked such that foldable bar 78 becomes rigid, thereby providing increased support to the wheel unit 70. FIG. 12 depicts a side view of a third type of collapsible wheel frame unit 80. This embodiment comprises a front set of wheels 86 and a rear set of wheels 84. The wheel unit further comprises a collapsible platform 90 that allows the front wheels to fold underneath and up in between the rear wheels and snap up inside of wheel frame unit 82. This is accomplished via the use of a locking hinge device 88. This design allows the front wheel to be retracted when used as a carrier, and be deployed when used as a stroller. The unit may be attached to rear frame support member 12 via connector 92. While these depictions present only a few possible collapsible wheel unit designs, it is also envisioned that any of the known baby stroller art which utilizes collapsible wheel systems could also be used. The foregoing description of the preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. Such modifications and variations that may be apparent to a person skilled in the art are intended to be included within the scope of this invention as defined by the accompanying claims.
The present invention provides a releasably mounted retrofit system that allows a standard back-mounted child carrier to also serve as a stroller. The retrofit system comprises an adjustable handlebar apparatus and a wheel unit. Both of these can be releasably mounted to the rear frame of an existing back-mounted child carrier thereby allowing existing carriers to also function as strollers.
1
BACKGROUND OF THE INVENTION Heretofore, corner pieces for use in building construction, or for the assembly of partitions or the like, were either fabricated at the erection site from available materials or comprised prefabricated members which were manually held in place while being assembled with the structure and secured in fixed relation to the building structure. Corner pieces of sheet metal have been utilized to provide a closure at such positions and metal angle sections, or other formations, have been used to frame a corner, but with these prior arrangements it has been necessary physically to maintain such members in proper relation to the supporting structure while the member was being secured. Such practices were time consuming and frequently difficult and consequently expensive from the standpoint of labor and the man hours involved in completing structures of this type. SUMMARY OF THE INVENTION This invention provides a one piece corner trim member especially designed for use on outside corners of building structures, or partitions. The corner piece comprises an extrusion in its preferred form and is formed from a suitable plastic material such as a rigid vinyl. The extruded section is cut to length as required or designed for specific installations. The extrusion is formed to include an integral barb at an inner side which acts as a holding member for retaining the corner piece in proper position while it is being secured in place. The barb is integral with an inwardly extending web, or flange and is adapted to enter between the opposed surfaces of an opening provided in a building or partition structure into which it is driven, or pushed, in order to hold the corner piece in place by the gripping action of the opposed surfaces thereon until the corner member is fixedly adhered to the structure. The corner piece can be fixed to the building structure by a suitable mastic placed on the inside walls of the corner piece whereby when the attaching barb is pushed, or forced into the retaining opening, the mastic will be brought into contact between the building corner and the inner surfaces of the corner piece so that the trim piece will thereby be cemented in place and held against displacement. OBJECT OF THE INVENTION It is the primary purpose of this invention to provide a corner trim piece for outside corners of buildings, or partitions, having an integral member engageable with the building structure to hold the trim piece in position until it is adhered to the building. The principal object of the invention is the provision of a corner trim piece of one piece construction having a member for holding the trim piece in position while being adhered. An important object of the invention is to provide a corner trim piece having an integral barb projecting from an inner side to engage an opening provided in the building to hold the corner trim piece in proper relation to the building corner. Another object of the invention is the provision of a corner trim piece formed as an extruded section having an integral barb on an inward side thereof for engaging a structure to hold the corner piece in place. A further object of the invention is to provide a corner trim piece formed as an extrusion from a plastic material such as rigid vinyl having an integral retaining barb on an inner side and provided with one or more inside pockets for a mastic adapted to adhere the corner piece to a supporting structure. DESCRIPTION OF THE DRAWINGS The foregoing and other and more specific objects of the invention are attained by the construction and arrangement illustrated in the accompanying drawings wherein: FIG. 1 is a general perspective view of a portion of a building structure at a corner thereof with parts illustrated in section and showing the one piece corner time piece of this invention adhered in place about the building corner; and FIG. 2 is a detail cross-sectional view through the corner piece clearly illustrating the integral barb forming the prime element of this invention. DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, as shown in FIG. 1, the structure of a building is illustrated as typically utilized adjacent an outside corner thereof and includes vertical framing elements 10 and 11 which, as disclosed here, comprise metallic sections of open channel shaped configuration to which outside walls 12 and 13 are secured. As indicated, the wall 12 extends beyond the framing member 10 adjacent to the corner and the edge of the wall member 13 is spaced somewhat from the projecting portion of the wall member 12 to provide an opening 14 therebetween for a purpose hereinafter to appear. An inner wall member 15 is spaced from the outside wall member 13 and extends between the framing members 10 and 11 with the framing member 10 disposed between the outer and inner walls 13 and 15. An inner wall 16 is butted edgewise against the inside face of the wall member 15 and bears against the inner face of the framing member 11. All of the wall forming members 12, 13, 15 and 16 are secured to the framing members 10 and 11 in any manner preferred to provide a securely rigid structure. A corner trim piece 17 is utilized to give the outside corner of the building structure a completely weatherproof closure and a finished appearance. This corner piece comprises an extrusion which is extruded from a plastic material such as a rigid vinyl and the material may include a coloring ingredient if desired. The rim piece 17 is formed with flanges 18 and 19 extending generally at right angles to each other and at the extremities, or free edge of each flange a thickened, or bulb portion 20 and 21 on the respective flanges is formed integrally with the flanges. This creates pockets 22 and 23 on the inner side of the flange 18 and pocket 24 on the inner surface of the flange 19. These pockets have the effect of providing a space between the flanges 18 and 19 of the corner piece and the respective outside wall members 13 and 12, as represented by the thickness of the bulb portions 20 and 21 and insure a tight engagement of the thickened bulb portions with the respective building walls. The corner piece flange 18 is provided with an inwardly projecting flange 25 which terminates at its inner end in a barb 26. The barb 26 tapers to a point 27 at its forward end and has relatively sharp shoulders 28 at its rear portion projecting laterally from respectively opposite sides of the flange 25. When the corner trim piece 17 is assembled onto the corner of the building wall the barb member 26 is pushed, or forced into the opening 14 between the edge of wall member 13 and the adjacent inside face of wall member 12. The point 26 of the barb readily enters the space between the wall members and the tapered surfaces of the barb enable the wider shoulder portions 28 to be forced into the cavity under pressure and the resistance, or force of the engagement of the wall portions on the opposing shoulders of the barb serves to hold the barb against withdrawal and thus retains the corner piece in proper position on the corner until it is finally adhered to building structure. The corner piece may be secured to the building structure in any preferred manner but as shown in FIG. 1 the herein disclosed method of adhering the trim piece to the corner of the building is by means of a mastic 29 placed in the inner pockets 23 and 24 of the corner piece so that when the member is pressed onto the building corner this cement will come in contact with the corner of the building and spread along both sides of the corner to provide a secure attachment between the inner surfaces of the corner piece and both sides of the building corner. The invention has been disclosed as applied with a typical partition corner of conventional gypsum wallboard and metal stud construction, but the invention can just as well be used with other types of interior and exterior wall structures such as with wood paneling, aluminum siding, wood siding or vinyl siding. The invention can be used with practically any type of building or partition structure where a corner trim piece of this type may be required to close or complete a corner installation and provide a weatherproof finished appearance for the building corner. The embodiment disclosed is presently considered to be the preferred form of the invention but changes or modifications may be made differing from this disclosure and it is intended that the claims appended to this specification shall cover all such changes or modifications as may fall within the purview of this invention.
This invention pertains to an integral one piece corner trim member for an outside corner of a building structure or interior partition wherein the trim piece comprises an extruded section formed from a suitable vinyl material and having an integral barb at the inner side thereof to hold the corner piece in position on the building structure until it is fixedly secured to the building walls.
4
BACKGROUND OF THE INVENTION This invention relates generally to adjustable retention of helmets, as for example are used by bicycle or motorcycle riders; more particularly, it concerns a very simple retention system employing few parts and providing for universal adjustment of the helmet on the wearer's head. The invention is especially adapted for use with lightweight, plastic helmets as will be described. SUMMARY OF THE INVENTION It is a major object of the invention to provide an unusually advantageous helmet retention system that basically comprises: A. left and right side retention strap sections, the left section having attachments to the helmet at forward and rearward locations, and the right section having attachments to the helmet at forward and rearward locations, the sections hanging from the helmet, B. left and right sliders respectively slidably attached to the left and right retention straps to be adjustably slidable therealong, and C. chin strap means having attachment to and hanging from the sliders to extend therebetween. As will appear, the sliders may comprise like plates containing forward and rearward slits for passing the left and right retention strap sections, and vertically spaced horizontal slits to pass looping portions of the chin strap sections; the left and right retention strap sections may comprise a single strap attached to the rear of the helmet via angled slits in the helmet, and adjustably attached to the left and right sides of the helmet via additional slits. Further, the chin strap means typically includes primary and secondary sections adjustably interconnected via D-rings as will be described, the sliders supporting those sections. As a result, the sliders may be adjustably shifted along the left and right retention strap sections to control forward or rearward tilting of the helmet; the closeness of the sliders to the wearer's ear may be adjusted by adjusting the attachments of the retention strap sections to the helmet; and the tightness of the chin strap means may also be adjusted. These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following description and drawings, in which: DRAWING DESCRIPTION FIG. 1 is a side elevation of a helmet and retention system; FIG. 2 is an enlarged side elevation of a slider and associated strap; FIG. 2a is a vertical section on lines 2a--2a of FIG. 2; FIG. 3 is a side elevation of the slider seen in FIG. 2; FIG. 4 is a view like FIG. 3 showing a retention strap section passing through slits in the slider; FIG. 5 is an elevation on lines 5--5 of FIG. 1, showing anchorage of the retention strap to a rear portion of the helmet; FIG. 6 is an enlarged vertical section through a side portion of the helmet, and looking rearwardly, to illustrate left retention strap section attachment to the helmet; FIG. 7 is a vertical elevation showing chin strap sections in relation to D-rings; and FIGS. 8-12 are side elevations showing different positions of the helmet on the wearer's head. DETAILED DESCRIPTION In FIGS. 1, 5 and 9 the system shown includes left and right retention strap sections 10 and 11, the left sections having attachments to the helmet 12 at forward and rearward locations 13 and 14, and the right section having attachments to the helmet at forward and rearward locations 15 and 14. Note that the sections both hang from the helmet, the forward locations 13 and 15 being located about 1/4 to 1/3 of the way from the front to the rear, and that the rearward locations 14 are common or near one another. The sections 10 and 11 may consist of one continuous strap passing through upwardly tapering slits 16 and 17 in the rearwardmost portion of the helmet shell 12a. The sections merge at 18 at the outer side of the shell, whereby they pass downwardly at the inner side of the shell 12a rim bead 12b, as is clear from FIG. 5, and cross below the bead. Left and right sliders, as at 20, are respectively slidably attached to the left and right retention straps to be adjustably slidable therealong; in addition, chin strap means, generally indicated at 21, has attachment to the sliders and hangs therefrom as seen in FIG. 1. Each slider may, with unusual advantage, take the form of a plate containing forward and rearward slits for passing a retention strap section. As seen in FIGS. 2-4, the upright plate 22 contains forward and rearward slit 23 and 24 which are upwardly convergent, for directing the left retention strap sections in V-shape configuration beyond the slider edges 25 and 26, as shown. Note that section 10 extends at 10a at the outer side of the plate. Each slider plate also contains upper, middle and lower generally horizontal slits 30, 30a and 31 for passing a looping portion of the chin strap means. In FIGS. 2, 2a and 7, the left section 21a of the chin strap means extends upwardly, and outwardly through lower slit 31 as two overlapping portions 21a' and 21a"; portion 21a' extends back through slit 30a and then upwardly and through upper slit 30 to merge with portion 21a" at the outer side of the slider. The portion 21a" overlaps portion 10a of section 10, at the outer side of the plate, as seen in FIG. 2a, tending to frictionally hold the portion 10a clamped against the plate, during usage. The edges of slits 23 and 24 also tend to position the slider lengthwise of the retention strap 10. The other section 21b of the chin strap means may be similarly retained by the slider associated with retention strap 11. Referring to FIGS. 2 and 7, two D-rings 35 and 36 are provided and suspended by a looping portion 37 of the chin strap means. Portion 37 may be integral with section 21a, as described above. The secondary section 21b of the chin strap means laces through the first ring 35 and then through the second ring 36; it then loops about the outer side of a lateral leg 36a of ring 36, at locus 21b', and then extends at 21b" back through the first D-ring 35 adjacent and at the inner side of its lateral leg 35a. When chin strap end 21b'" is pulled tight, the chin strap tightens against the wearer's chin or jaw, and the strap 21b is retained by the clamping action of the D-rings. A pull-tab 38 integral with ring 35 may be pulled to the right in FIG. 7 to loosen the chin strap means. Referring now to FIG. 6, the forward attachment at 13 and 15 advantageously include vertically spaced perforations in the left and right side of the typically plastic helmet, and through which the left and right retention strap sections extend, respectively. FIG. 6 which looks rearwardly at the left retention strap section attachment, illustrates the provision of three vertically spaced, horizontally extending, perforations 40, 41 and 42 through the helmet shell 12a. The left retention strap section 10 extends upwardly into the shell between bead 43 and inner cushion 44, then outwardly through lower slit 42, then upwardly at 10' to enter inwardly via slit 40 into the helmet, then downwardly at 10" between the shell and cushion 44, then back outwardly through middle slit 41, then downwardly at 10'", and then back inwardly through lower slit 42 to terminate at 10"". Accordingly, a looping configuration is formed, which is loosenable and adjustable to adjust the chin strap means. Thus, to raise the adjusting plates, the strap extent 10' is pulled outwardly to enlarge the loop as seen in FIG. 9 and inner strap extent 10"" is pulled downwardly; this procedure is carried out at both attachment locations 13 and 15 using both straps 10 and 11. Reversal of this procedure lowers the plates and the chin strap. The plates 22 should fit just below the ears as in FIG. 8. The helmet 10 should sit level on the wearer's head, as in FIG. 11. If the helmet is tilted too far down in front, as in FIG. 10, obstructing vision, the sliders 20 are moved rearwardly on the straps 10 and 11. If the helmet is tilted too far to the rear as in FIG. 12, the sliders may be moved forwardly on straps 10 and 11 until the helmet seats properly as in FIG. 11. Note that very simple construction and unusual adjustment of the helmet is provided for, as enabled by the sliders and their relationship to the retention and chin straps, and by adjustment of the straps as described. Merely as illustrative, the outer helmet 12a may consist of LEXAN, and the inner cushion 44 of polystyrene.
A helmet retention system including a forwardly facing helmet comprises, A. left and right side retention strap sections, the left section having attachments to the helmet at forward and rearward locations, and the right section having attachments to the helmet at forward and rearward locations, the sections hanging from the helmet, B. left and right sliders respectively slidably attached to the left and right retention straps to be adjustably slidable therealong, and C. chin strap means having attachment to and hanging from the sliders to extend therebetween.
0
TECHNICAL FIELD This invention relates to semiconductor devices, and more particularly to methods for passivating such semiconductor devices. BACKGROUND As is known in the art, one type of semiconductor device is high electron mobility transistor (HEMT). As is known in the art, such devices are typically used at microwave and millimeter frequencies to provide amplification of radio frequency signals. Typically, HEMTs are formed from Group III-V materials such as gallium arsenide (GaAs) or indium phosphide (InP). In a HEMT there is a doped donor/undoped spacer layer of one material and an undoped channel layer of a different material. A heterojunction is formed between the doped donor/undoped spacer layer and the undoped channel layer. Due to the conduction band discontinuity at the heterojunction, electrons are injected from the doped donor/undoped spacer layer into the undoped channel layer. Thus, electrons from the large bandgap donor layer are transferred into the narrow bandgap channel layer where they are confined to move only in a plane parallel to the heterojunction. Consequently, there is spatial separation between the donor atoms in the donor layer and the electrons in the channel layer resulting in low impurity scattering and good electron mobility. Thus, with a HEMT, a quantum well is formed between a large bandgap material (InAlAs in MHEMTs) and a small bandgap, high electron mobility channel (In0.60Ga0.40As) channel below it. Silicon, Si, doping is used to introduce electrons for conduction of current. The Si doping is insertion in the InAlAs at the interface with the InGaAs. The electrons all move in the InGaAs and the donors stay in the InAlAs. The electrons can thus achieve high mobility, because they travel in the InGaAs and avoid ionized-impurity scattering due to separation from the donor Si atoms. One type of HEMT is a pseudomorphic HEMT (pHEMT). Such pHEMTs are formed on GaAs wafers, using strained InGaAs layers for the small bandgap channel layer with ˜18-20% indium. As is also known in the art, metamorphic HEMTs (MHEMTs) are promising devices for solid-state power generation above 60 GHz. MHEMTs are formed on GaAs wafers that use a grading layer to transform the lattice constant from GaAs to near InP. Once this is done, strain-free layers of InGaAs with 53-60% indium can be grown. InAlAs forms the large bandgap layer. The gate electrode is in Schottky contact with this InAlAs layer. The MHEMTs are nearly identical to InP HEMTs except for the substrate. It should be noted that these devices also have a layer of InGaAs above the wideband layer, but it is used only for making ohmic contact. An opening is formed in this layer to put the gate electrode metal down, on the InAlAs layer, to form the Schottky contact. MHEMTs offer considerably higher gain and efficiency as compared to established GaAs pHEMT technology at nearly the same cost. However, they suffer from surface states between the gate and drain which accumulate electrons and reduce the sheet electron density in the semiconductor channel between gate and drain. This decrease of electron density is passivation dependent and results in increased source and drain resistances, Rs and Rd along with a reduction of the peak drain current capability, Imax. The current reduction, called IV collapse, is most severe when the device's gate voltage is pulsed from −3V to 0V with greater than 0.5V on the drain. Additional reductions in Imax and device gain, Gm, occur gradually under high temperatures. Since the above conditions are encountered under RF power drive and bias, MHEMTs with standard silicon nitride passivation are expected to suffer poor reliability in power RF applications as measured by degradation in RF output power and gain. Most attempts to solve this reliability problem involve filling an etched gate recess trench with gate metal. This technique attempts to reduce the effect of electron traps, at the semiconductor surface, by allowing the use of a thicker Schottky barrier layer that moves the semiconductor surface with its trapped electrons, farther from the HEMT channel. The resulting increased distance between the trapped electrons and HEMT channel reduces the ability of the trapped electrons to reduce the channel's electron density. In order for the above method to work well, one must ensure that the gate metal covers the sidewalls of the gate recess trench so that no surface traps are left which would be close to the channel. This implies a minimum of undercut (ungated region) during the gate recess etch. Additionally, the gate metal must not contact the highly conductive cap layer since this would result in a short-circuit of the gate. Such requirements force one to fabricate a complicated double-recessed gate structure in which the gate length and/or ungated region is sensitive to gate etch time and hence difficult to control. SUMMARY In accordance with the present invention, a method is provided for passivating a III-V material Schottky layer of a field effect transistor. The transistor has a gate electrode in Schottky contact with a gate electrode contact region of the Schottky layer. The gate electrode is adapted to control a flow of carriers between a source electrode of the transistor and a drain electrode of such transistor. The transistor has exposed surface portions of the Schottky layer beween the source electrode and the drain electrode adjacent to the gate electrode contact region of the Schottky layer. The method includes first removing organic contamination from the exposed surface portions of the Schottky layer. The contamination removed surface portions of the Schottky layer are exposed to a sulfide solution, for example a solution of ammonium sulfide and NH 4 OH. After removal from the solution, the exposed regions are dried in nitrogen. A layer of passivating material is subsequently deposited over the dried surface portions. With such method, a passivation technique is provided which has been shown to significantly reduce IV collapse in MHEMTs subjected to pulsed drain voltages. Additional benefits of the new passivation technique are improved reliability with less decline in device transconductance (Gm) and maximum drain current (Imax) under prolonged thermal stress. The beneficial effects of this passivation technique require a high pH combined with encapsulation by silicon nitride. Furthermore, the passivation technique does not require careful timing of gate etching to prevent undercut and can work with selective gate etching to improve reliability and device uniformity. The Encapsulated Sulfide Passivation has been found to give good reliability even while allowing a large exposed Schottky layer area. This allows a single wide gate recess with high reliability while maintaining good manufacturability. The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. DESCRIPTION OF DRAWINGS FIG. 1 is a cross sectional sketch of a MHEMT at a stage in the manufacture thereof just prior to the passivation process used thereon according to the invention; FIG. 2 is a cross sectional sketch of the MHEMT of FIG. 1 after final passivation thereof in accordance with the invention; FIG. 3 is a plot illustrating the degradation of I max over time under a no-bias thermal stress. FIG. 4 is a plot illustrating the degradation of G mpeak over time under a no-bias thermal stress; FIG. 5 are DC IV families of curves superimposed on pulsed IV data formed by pulsing the gate of an MHEMT of FIG. 2 . Like reference symbols in the various drawings indicate like elements. DETAILED DESCRIPTION Referring now to FIG. 1 , a HEMT 10 , here an MHEMT is shown after fabrication of the source, drain and gate electrodes 12 , 14 and 16 , respectively. Here, in this example, the MHEMT uses a lattice-matching graded buffer layer 20 which matches a GaAs substrate 18 lattice constant to that of a MHEMT backside InAlAs layer 22 . Layer 20 allows growth of low-strain high-indium content channels which are conventionally observed in InP-based HEMTs. The MHEMT device is adapted to operate at the high frequencies with the low-noise performance characteristic of InP HEMTs and with the lower cost and better manufacturability associated with GaAs substrates. Thus the HEMT 10 includes the InAlAs backside layer 22 with an InAlGa channel layer 24 , as shown. An InAlAs Schottky layer 26 covers layer 24 to act as an electron barrier which reduces leakage currents between gate and layer 24 . The gate electrode 16 forms a Schottky contact with a portion 38 of the AlGaAs Schottky layer 26 for a gate length L g , as shown. An InGaAs n+ cap is grown as the last of the MHEMT layers and etched during the gate etch process to define the separate regions of 30 and 32 . Metal source and drain electrodes, 12 and 14 respectively, form low-resistance ohmic contacts to the regions 30 and 32 . The length L cs between the edge 34 of the source electrode 12 and the nearest edge 36 of the n+ cap layer 30 is L cs ; the length between the edge 40 of the drain electrode 14 and the nearest edge 42 of the n+ cap layer 32 is L cd . The edges of the gate electrode 16 are distance L gc away from both edges 36 and 42 , as indicated. It is noted that the source and drain electrodes, 12 and 14 form ohmic contacts with the n+ cap layer 30 and 32 . It is noted that the n+ cap layers 30 and 32 do not touch the gate electrode 16 metal. This process allows the gate and Lgc to be defined using only one resist pattern step. A selective gate etchant, which stops on the InAlAs Schottky layer, is timed to set the desired value of L gc . To make the gate etchant, a succinic acid solution is prepared by first mixing 200 gm solid succinic acid with 1000 ml de-ionized water. The pH of the succinic acid solution is adjusted, using NH 4 OH, to the range 5.1-5.3. After this, the succinic acid solution is filtered and stored. Within an hour of gate etch, the gate etchant is prepared by mixing six parts succinic acid solution with one part of a 30% solution of hydrogen peroxide. After fabrication of the structure shown in FIG. 1 , the upper surface of the structure is exposed to an oxygen plasma to remove organic contamination from exposed regions, 43 and 44 , of the InAlAs semiconductor surface. Next, the contaminate-free surface is dipped in a solution of 2 parts (NH 4 ) 2 S, 9 parts NH 4 OH for 10 seconds. The NH 4 OH and (NH 4 ) 2 S are 20% and 30% water solutions of NH 3 and (NH 4 ) 2 S respectively. After completion of the dip, the InAlAs Schottky surface is blown dry with nitrogen using a blower gun; i.e., a nitrogen spray). Next, a silicon nitride passivation layer 50 , as shown in FIG. 2 , is formed over the surface of the structure, here using a plasma chemical vapor deposition system (PCVD). The final structure is shown in FIG. 2 . In FIG. 2 , regions 43 and 44 are the interfaces between the InAlAs layer 26 and the silicon nitride layer 50 . The deposition of the silicon nitride passivation layer 50 prevents air from increasing the surface state density of the device at regions 43 and 44 . More particularly, surface states on the exposed InAlAs material region 43 , between gate and drain can accumulate trapped electrons under pulsed-IV conditions. The trapped electrons on region 43 will deplete electrons in layer 24 (InGaAs channel) and result in IV collapse. This IV collapse will reduce RF power output and gain under the high RF drive conditions encountered in HEMT-based RF power amplifiers. The use the (NH 4 ) 2 S based treatment as described above, reduces surface states on the exposed InAlAs in regions 43 and 44 . The silicon nitride passivation layer 50 is deposited to seal the treated surface and prevent degradation of regions 43 and 44 . We found that the use of ammonium sulfide solution alone would damage the MHEMT devices by etching the semiconductor layers 30 , 32 , and 26 . In accordance with the invention, the process uses concentrated NH 4 OH to obtain a high pH solution which ensures a high concentration of S −2 (i.e., sulfur) ions. This is necessary to obtain optimum passivation because these ions form a double bridging bond rather than the less-stable single bond formed by the HS − ions, which predominate at pH <13.6. Results The process described above has been found to improved stability under high-temperature stress without bias. In order to provide a controlled experiment by which to make a comparison, the base, or standard device process (without ammonium sulfide) included the following steps: 1. expose to an oxygen plasma to remove organic contaminants; 2. a dip for 10 sec in NH 4 OH: 3. blow dry with nitrogen; and 4. then deposit PCVD silicon nitride. To test both devices, the DC electrical characteristics were first measured before thermal stress. The devices were then baked in air at 300 C and then cooled and measured at room temperature at various time intervals and restored to the thermal stress bake between measurements. The results are shown in FIGS. 3 and 4 . The plots illustrate the degradation of room-temperature I max and G mpeak over time due to a no-bias thermal stress. I max is the maximum available MHEMT drain current, in mA per millimeter of gate width, at a drain-source voltage of 1V. G mpeak is the maximum DC transconductance. Each data point represents the average measurements of a set of four to nine devices. All devices are from the same wafer. MHEMT devices treated according to the Invention (i.e., the process with ammonium sulfide) show significantly less degradation under thermal stress as compared to control devices treated with ammonium hydroxide alone. FIG. 5 illustrates the pulsed IV curves from two MHEMTs. Each curve of the IV data is a locus of data points, drain current I ds vs. drain voltage V ds , measured at the same gate voltage, V gs . V gs is set to a different value for each curve in the family of IV curves. In both plots, the pulsed IV curves are superimposed over the DC IV curves. For the pulsed IV data the drain voltage is slowly swept from 0 V to 1.5 V while the gate-source voltage is pulsed from −3 V to V gsp , where V gsp is the value of gate voltage corresponding to the particular curve being traced out on the IV family of curves. The drain current is measured only during the time that the gate voltage is at V gsp . Each DC IV curve is plotted by holding V gs constant while sweeping V ds from 0 V to 1.5 V. V gs is stepped to a new value to produce a new DC IV curve. The left MHEMT IV plot is from a control device fabricated via a standard process and the right IV plot is from a device of FIGS. 1 and 2 which incorporated the invention during fabrication. The control MHEMT, in the left plot, shows a significant reduction of the pulsed drain current, I d at V ds <0.7V while the device incorporating the invention, in the right plot, showed a very slight difference between pulsed and DC IV curves. The improved pulsed IV characteristics of devices fabricated using the the invention should improve their RF power output and gain, with respect to the standard fabricated devices, especially under the high RF input drive conditions commonly found in RF power amplifiers. The pulsed IV plots are superimposed on DC IV plots. The pulsed IV data were formed by setting V ds and pulsing the gate from V gs =−3V to the on-state gate voltage as represented by each curve. The left MHEMT IV plot is from a control device fabricated via a standard process without using the invention. The right IV plot is from a device which incorporated the invention during fabrication. Both devices are from the same wafer. From the above, thermally driven degradation has been reduced and pulsed IV characteristics improved for improved RF power performance. Conventional methods to achieve similar results seek to reduce the effects of the InAlAs surface states by using a thick InAlAs Schottky layer 26 and recessing the gate metal into this layer and/or reducing L gc (FIG. 1 ). The former method moves the InAlAs surface states further from the channel, thus reducing their effects. The latter method reduces the surface state effects by reducing the exposed InAlAs surface area, i.e., region 43 . The recessed gate method generally requires a separate etch step to move the n+ cap the desired (L gc ) distance away from the gate metal to obtain an acceptably high gate-drain breakdown voltage. However, the conventional methods require one to perform at least two gate lithographies and etch procedures namely, the first recess, which removes only the n+ cap and sets L gc , followed by the gate lithography step which is used to pattern the gate and set the gate length, L g . Following the gate lithography step, a gate etch is performed to form a channel in the InAlAs, i.e. the gate recess, into which the gate metal is evaporated. The process according to the invention allows one to fabrication the gate using just one selective etch of the n+ cap layer. In this case, the gate etch is timed to give the correct amount of undercut which defines L gc . One need not etch the InAlAs because the InAlAs thickness can be set to produce the optimum electrical characteristics while the invention reduces the InAlAs surface states and their effects to low levels. Additionally, the invention allows more freedom to increase L gc to improve breakdown voltage with less regard to the effects of the InAls surface states. The process according to the invention uses a relatively safe and simple procedure to reduce surface states in MHEMT devices. It recognizes the need for high pH of the ammonium sulfide solution to obtain the optimum surface state reduction. It also recognizes the need to obtain the required high pH using a volatile alkaline material, e.g., ammonium hydroxide so as to avoid the need for a water rinse. A water rinse would likely remove the sulfide coating and reduce the effectiveness of the procedure. The invention also recognizes the need to coat the sulfide-treated surfaces with silicon nitride or some other hermetic encapsulant. The process, according to the invention, permanently reduces IV collapse and improves reliability under thermal stress. A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, the ratio of ammonium hydroxide solution to ammonium sulfide solution may be varied. Variations in the strength of the precursor ammonium hydroxide and/or ammonium sulfide shall also be considered an implementation of the invention. The invention will also include the above sulfide treatment of III-V field-effect transistors structures for all values of indium and/or aluminum content in the III-V field-effect transistors' material layer structures. Accordingly, other embodiments are within the scope of the following claims.
A method for passivating a III-V material Schottky layer of a field effect transistor. The transistor has a gate electrode in Schottky contact with a gate electrode contact region of the Schottky layer. The gate electrode is adapted to control a flow of carriers between a source electrode of the transistor and a drain electrode of such tarnsistor. The transistor has exposed surface portions of the Schottky layer beween the source electrode and the drain electrode adjacent to the gate electrode contact region of the Schottky layer. The method includes removing organic contamination from the exposed surface portions of the Schottky layer using a oxygen plasma. The contamination removed surface portions of the Schottky layer are exposed to a solution of ammonium sulfide and NH 4 OH. After removal of the solution, the exposed regions are dried in a nitrogen enviroment. A layer of passivating material is deposited over the dried surface portions.
7
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tent part, and more particularly to a top support structure of a tent frame. 2. Description of the Prior Art A conventional automatic extendable tent frame comprises a top pivot holder. The pivot holder has pivot troughs for connection of support poles and elastic units which correspond in number to the support poles. When the support poles are folded downward with respect to the pivot holder, the elastic units provide elasticity. Each support pole is movably connected to the pivot holder and rotatable with relative to the pivot holder. One end of each elastic unit is connected to the support pole and another end of each elastic unit is connected to the pivot holder. It is required to apply a force to retract the support poles inward when folding the tent. When unfolding the tent, the restoring force of the elastic units will expand the support poles up relative to the pivot holder, providing an automatic extendable function. This shows that the top support frame of this tent depends on the elasticity of the elastic units. If the top of the tent is applied with a force, the support poles are easy to be folded downward. Thus, the support strength of the support poles is not enough. The outer support poles may be raised relative to the pivot holder subject to the elastic action of the elastic units. When the tent is influenced by wind force or external force, the tent frame is easy to shake. The tent lacks support stability. SUMMARY OF THE INVENTION The primary object of the present invention is to provide a top support structure to strengthen a tent frame, preventing support poles from folding downward when the top of the tent is applied with a force. A further object of the present invention is to provide a top support structure to ensure the stability of the tent frame, with a better raised angle of the support poles. In order to achieve the aforesaid objects, the solution of the present invention is to provide a top support structure of a tent frame. The top support structure comprises a top pivot holder. The pivot holder is pivotally connected with support poles. An elastic member is provided between the pivot holder and each of the support poles. The elastic member is bent to store an elastic energy when the tent frame is folded. The elastic member will automatically spring a corresponding support pole when the elastic energy is released. Wherein a control holder is provided under the pivot holder and pivotally connected to the pivot holder. The control holder comprising lock pieces to hold against the support poles and to limit rotation of the support poles and release troughs each disposed between two of the adjacent lock pieces. The pivot holder has pivot troughs to receive the support poles therein. A position-limit device is provided on each of the pivot troughs to prevent the support poles from moving upward. Each of the support poles is pivotally connected in a corresponding pivot trough through a connection head. A metallic sleeve is provided between the connection head and a connection part of each of the support poles to enhance connection of the support pole and the connection head. The connection head has a neck at a rear part thereof. The neck is inserted in a corresponding support pole. A metallic rod is provided in the neck to enhance the neck. The control holder has an arc guide slot. A guide post is connected with the pivot holder and inserted through the guide slot. The central angle of the guide slot is equal to the central angle between two adjacent release troughs. The control holder comprises a handle disposed under the control holder. A metallic plate is provided in or on the control holder. The position-limit device includes a positioning hole and a fixing hole disposed on two side walls of each of the pivot troughs of the pivot holder. A rotation shaft is inserted through a shaft hole of the support pole and fixed in the fixing hole. A positioning shaft is fixed in the positioning hole to block the support pole from moving upward. The position-limit device includes a positioning hole and a fixing hole disposed on two side walls of each of the pivot troughs of the pivot holder. A rotation shaft is inserted through a shaft hole of the connection head and fixed in the fixing hole. A positioning shaft is fixed in the positioning hole to block the connection head from moving upward. The positioning shaft is located above an outer side of the rotation shaft. One end of the elastic member is fixed to an inner side of the pivot holder, and the other end of the elastic member is fixed to the support pole. The positioning shaft is located above an outer side of the rotation shaft. One end of the elastic member is fixed to an inner side of the pivot holder, and the other end of the elastic member strides over the positioning shaft and is fixed to the connection head. The position-limit device includes a crescent groove of the connection head. The crescent groove is disposed between a top end of the connection head and a shaft hole. Two side walls of each of the pivot troughs of the pivot holder have a positioning hole and a fixing hole under the positioning hole. A rotation shaft is inserted through a shaft hole of the connection head and fixed in the fixing hole. A positioning shaft is fixed in the positioning hole and inserted through the crescent groove of the connection head to block the connection head from moving upward. The position-limit device is a stop block which is integrally formed with each of the pivot troughs of the pivot holder. A corresponding support pole is located under the stop block and pivotally connected in a corresponding pivot trough. The stop block has concave upper and lower surfaces. A first end of the elastic member is fixed to an inner side of the pivot trough, and a second end of the elastic member strides over the stop block and is connected to a corresponding support pole. Each of the pivot troughs of the pivot holder is provided with a fixing axle to connect with one end of the elastic member. Each of the support poles is provided with a connection block. The connection block has a connection axle to connect another end of the elastic member. The connection block is provided with a hook underneath the connection block. A metallic sleeve is provided between the connection block and the connection head. Each of the pivot troughs of the pivot holder is provided with a decoration cover to cover a corresponding support pole. A front portion of the decoration cover is shaped like a hook and has a crescent groove and a shaft hole. The crescent groove and the shaft hole corresponding to a crescent groove and a shaft hole of a connection head. A rotation shaft is inserted through the shaft hole of the decoration cover and the shaft hole of the connection head to connect the decoration cover with the connection head. The top support structure of a tent frame further comprises a top cover which is fixed on top of the pivot holder. Accordingly, the rotatable control holder is provided under the pivot holder. The lock pieces and the release troughs of the control holder are turned to correspond to the pivot troughs of the pivot holder for the release troughs to be under the pivot troughs, such that the support poles can be turned relative to the pivot troughs (The control holder won't restrict turning of the support poles.) to fold the tent frame. The control holder is turned to achieve the aforesaid effect. This is convenient and quick way to fold the tent frame. When the tent is in an unfolded state, the lock pieces will be located under the pivot troughs. The support poles are supported on the lock pieces and can't be moved or folded downward. The tent frame is unfolded steadily. Besides, the pivot holder is provided with the position-limit device to restrict the angle of the support poles to be moved upward, so the support poles are steady after the tent is unfolded. By the control holder to position the support poles, the unfolded tent frame has upper and lower positioning effects to secure the tent firmly. Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded view according to a first embodiment of the present invention; FIG. 2A , FIG. 2B and FIG. 2C are a top perspective view, a bottom perspective view and a cross-sectional view of the pivot holder according to the first embodiment of the present invention; FIG. 3 is a perspective view of the control holder of the present invention; FIG. 4A , FIG. 4B and FIG. 4C are a perspective view, a front view and a top view of the connection head according to the first embodiment of the present invention; FIG. 4D is a perspective view of another embodiment of the connection head of the present invention; FIG. 5A , FIG. 5B and FIG. 5C are a perspective view, a front view and a top view of the decoration cover according to the first embodiment of the present invention; FIG. 6 is a perspective view according to the first embodiment of the present invention; FIG. 7 is partially schematic view according to the first embodiment of the present invention; FIG. 8 is a perspective view according to a second embodiment of the present invention; FIG. 9 is a perspective view according to a third embodiment of the present invention; FIG. 10 is a perspective view of the pivot holder according to the third embodiment of the present invention; and FIG. 11 is a front view according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1 , FIG. 6 and FIG. 7 , a top support structure of a tent frame according to a first embodiment of the present invention is connected with support poles 10 and elastic members 9 . The elastic members 9 will be bent to store elastic energy when the tent is folded. The elastic members 9 can automatically spring the support poles 10 when the elastic energy is released. The top structure comprises a pivot holder 1 , a control holder 2 , four connection heads 3 , a decoration cover 4 , a rotation shaft 5 , a position-limit device D, and a top cover 7 . The position-limit device D includes a positioning shaft 6 and a crescent groove 35 of the connection head 3 . The top cover 7 is coupled to the pivot holder 1 . The control holder 2 is pivotally connected to the pivot holder 1 and rotatable with respect to the pivot holder 1 . Inner ends of the four connection heads 3 are inserted through the notches 71 of the top cover 7 and pivotally connected to the pivot holder 1 , respectively. Outer ends of the four connection heads 3 are connected to the support poles 10 , respectively. As shown in FIGS. 2A , 2 B, and 2 C, the pivot holder 1 comprises a base 11 . The base 11 has four pivot troughs 12 which are equally spaced, a pair of ribs 13 at two sides of each of the pivot troughs 12 , and spaced positioning protrusions 14 disposed under the base 11 . The pivot trough 12 is defined between the pair of ribs 13 . Each of the pair of ribs 13 is formed with a positioning hole 16 and a fixing hole 15 under the positioning hole 16 . The rotation shaft 5 is inserted through a shaft hole 33 of the connection head 3 and fixed in the fixing hole 15 . The positioning shaft 6 is fixed in the positioning hole 16 . As shown in FIG. 3 , the control holder 2 comprises a control plate 21 and a handle 22 under the control plate 21 . The control plate 21 has four lock pieces 211 to hold against the support poles 10 and to limit rotation of the support poles 10 . A release trough 212 is formed between two adjacent lock pieces 211 . Each of the lock pieces 211 has an arc guide slot 213 . The axis of the guide slot 213 is overlapped with the axis of the control holder 2 . The central angle of the guide slot 213 is equal to the central angle between two adjacent release troughs 212 . In order to enhance the strength of the control holder 2 , a metallic plate 214 may be provided in or on the control plate 21 . Referring to FIG. 1 and FIG. 3 , the pivot holder 1 is provided with a guide post 8 . A lower end of the guide post is moveably connected in the arc guide trough 213 , so the control holder 2 under the pivot holder 1 is rotatable with respect to the holder 1 . Outer edges of the lock pieces 211 of the control holder 2 are exposed out of an outer edge of the pivot holder 1 . The spaced positioning protrusions are against a top surface of the control holder 2 , such that a space is formed between the pivot holder 1 and the control holder 2 . Due to the space, the support poles 10 are slightly oblique downward when they are in a locked state. As shown in FIGS. 4A , 4 B, and 4 C, each of the connection heads 3 comprises a connection post 31 and a pair of connection lugs 32 at one end of the connection post 31 . The pair of connection lugs 32 has the shaft hole 33 for insertion of the rotation shaft 5 . The pair of connection lugs 32 is larger in area than the connection post 31 . The connection post 31 has an inner axial hole 34 for insertion of a corresponding support pole 10 to be secured thereat. The pair of connection lugs 3 has the crescent groove 35 for insertion of the positioning shaft 6 . The crescent groove 35 is disposed between a top end of the connection head 3 and the shaft hole 33 . The positioning shaft 6 is inserted through the positioning hole 16 and secured in the crescent groove 35 of the connection head 3 to stop the connection head 3 from moving upward. As shown in FIG. 4D , the connection head 3 has a neck 34 instead of the axial hole 34 . A metallic rod 341 is provided in the neck 34 to enhance the strength of the neck 34 . The metallic rod 341 is connected to the support pole 10 . Referring to FIGS. 5A , 5 B, 5 C, a front portion of the decoration cover 4 is shaped like a hook and has a crescent groove 41 and a shaft hole 42 . The crescent groove 41 and the shaft hole 42 correspond to the crescent groove 35 and the shaft hole 33 of the connection head 3 . The rotation shaft 5 is inserted through the shaft hole 42 of the decoration cover 4 and the shaft hole 33 of the connection head 3 to connect the decoration cover 4 with the connection head 3 . As shown in FIG. 1 , FIG. 6 and FIG. 7 , to assemble the present invention, an upper end of each support poles 10 is inserted into the axial hole 34 of the connection post 31 of the connection head 3 . In order to enhance the strength of the connection post 31 , the connection post 31 may be provided with a metallic sleeve. The connection head 3 is located in the pivot trough 12 of the pivot holder 1 . The rotation shaft 5 is inserted in the fixing holes 15 of the pair of ribs 13 of the pivot holder 1 and the shaft holes 33 of the pair of lugs 32 of the connection head 3 , so the support pole 10 is pivotally connected in the pivot trough 12 of the pivot holder 1 . Referring to the FIG. 7 , a first end of the elastic member 9 is fixed to a fixing axle 92 , and a second end of the elastic member 9 is inserted through the pair of connection lugs 32 and connected to the support pole 10 . The support pole 10 is provided with a connection block 101 . The connection block 101 has a connection axle 91 to connect the second end of the elastic member 9 . The elastic member 9 will generate elasticity when bent. In order to prevent the connection block 101 from loosening after a period of time, a metallic sleeve 102 is provided between the connection block 101 and the connection head 3 to limit the connection block 101 and to enhance the strength of the joint of the support pole 10 and the connection head 3 . When folding the tent frame, the elastic member 9 will be bent to store elastic energy. The elastic energy will automatically spring the support pole 10 when the elastic member 9 is released. To fold the tent frame, the control holder 2 is turned for the arc guide slot 213 to correspond to the guide post 8 . When the release trough 212 is aligned with the pivot trough 12 , the user can move the support poles 10 downward with respect to the pivot holder 1 to bend the elastic members 9 . To unfold the tent frame, the elastic energy is released to spring the support poles 10 , and the control holder 2 is turned for the lock pieces 211 to be located under the pivot troughs 12 , and the connection heads 3 are against the lock pieces 211 , so the support poles 10 are unfolded steadily. FIG. 8 shows a second embodiment of the present invention, which is substantially similar to the first embodiment with the exceptions described hereinafter. The position-limit device D is the positioning hole 16 and the fixing hole 15 formed on two side walls of the pivot trough 12 of the pivot holder 1 . The two side walls are formed with, respectively. The support pole 10 is pivoted in the pivot trough 12 through the rotation shaft 5 . The positioning shaft 6 is located above the rotation shaft 5 . The first end of the elastic member 9 is fixed to the fixing axle 92 which is located at an inner side of the pivot trough 12 . The second end of the elastic member 9 strides over the positioning shaft 6 and is connected to the connection axle 91 of the connection block 101 of the support pole 10 . In this embodiment, the positioning shaft 6 also prevents the support pole 10 from moving upward. The support pole 10 is also connected to the pivot holder 1 through the connection head 3 . FIG. 9 and FIG. 10 show a third embodiment of the present invention, which is substantially similar to the first embodiment with the exceptions described hereinafter. The position-limit device D is a stop block 17 which is integrally formed with the pivot trough 12 of the pivot holder 1 . The stop block 17 has concave upper and lower surfaces. The support pole 10 is located under the stop block 17 and pivotally connected in the pivot trough 12 . The first end of the elastic member 9 is fixed to the fixing axle 92 which is located at an inner side of the pivot trough 12 . The second end of the elastic member 9 strides over the stop block 17 and is connected to the connection axle 91 of the connection block 101 of the support pole 10 . The stop block 17 provides a limit effect to the unfolded support pole 10 . As shown in FIG. 11 , the connection block 101 may be provided with a hook 103 underneath the connection block 101 to secure the tent cloth. The feature of the present invention is that the rotatable control holder 2 is provided under the pivot holder 1 . The lock pieces 211 and the release troughs 212 of the control holder 2 are turned to correspond to the pivot troughs 12 of the pivot holder 1 for the release troughs 212 to be under the pivot troughs 12 , such that the support poles 10 can be turned relative to the pivot troughs 12 (The control holder 2 won't restrict turning of the support poles 10 ) to fold the tent frame. The control holder 2 is turned to achieve the aforesaid effect. This is convenient and quick way to fold the tent frame. When the tent is in an unfolded state, the lock pieces 211 will be located under the pivot troughs 12 . The support poles 10 are supported on the lock pieces 211 and can't be moved or folded downward. The tent frame is unfolded steadily. Besides, the pivot holder 1 is provided with the position-limit device D to restrict the angle of the support pole 10 to be moved upward, so the support poles 10 are steady after the tent is unfolded. By the control holder to position the support poles 10 , the unfolded tent frame has upper and lower positioning effects to secure the tent firmly. Although particular embodiments of the present invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the present invention. Accordingly, the present invention is not to be limited except as by the appended claims.
A top support structure of a tent frame includes a top pivot holder ( 1 ), to which a plurality of support poles ( 10 ) are pivotally coupled. An elastic member ( 9 ) is provided between each support pole and the pivot holder. The elastic member folds and stores elasticity energy when the tent frame is folded and automatically springs the support poles when the elasticity energy is released. A control holder ( 2 ) is pivotally coupled to the bottom of the pivot holder, and the control holder has lock pieces ( 211 ) which can prop the support poles up to limit their rotation and release grooves ( 212 ) adjacent to the lock pieces which can release the limitation. On the top of pivot grooves ( 12 ) of the pivot holder are provided with position-limited devices (D) to prevent the support poles from rotating upwards.
4
FIELD OF THE INVENTION [0001] The present invention provides novel methods for treating diseases of the nervous system, e.g., neuromuscular disorders and conditions, with botulinum toxins. In addition, the present invention provides methods useful in all tissue and organ systems which involve the release of neurotransmitters, especially acetylcholine. These cholinergic transmission systems include neuromuscular junctions (muscles), smooth muscles (gut, sphincters, etc.) and secretions (salivation and mucus). BACKGROUND OF THE INVENTION [0002] A bacterial toxin, botulinum toxin, in particular botulinum toxin type A, has been used in the treatment of a number of neuromuscular disorders and conditions involving muscular spasm; for example, strabismus, blepharospasm, spasmodic torticollis (cervical dystonia), oromandibular dystonia and spasmodic dysphonia (laryngeal dystonia). The toxin binds rapidly and strongly to presynaptic cholinergic nerve terminals and inhibits the exocytosis of acetylcholine by decreasing the frequency of acetylcholine release. This results in local paralysis and hence relaxation of the muscle afflicted by spasm. [0003] For one example of treating neuromuscular disorders, see U.S. Pat. No. 5,053,005 to Borodic, which suggests treating curvature of the juvenile spine, i.e., scoliosis, with an acetylcholine release inhibitor, preferably botulinum toxin A. [0004] For the treatment of strabismus with botulinum toxin type A, see Elston, J. S., et al., British Journal of Ophthalmology, 1985, 69, 718-724 and 891-896. For the treatment of blepharospasm with botulinum toxin type A, see Adenis, J. P., et al., J. Fr. Ophthalmol., 1990, 13 (5) at pages 259-264. For treating squint, see Elston, J. S., Eye, 1990, 4(4):VII. For treating spasmodic and oromandibular dystonia torticollis, see Jankovic et al., Neurology, 1987, 37, 616-623. [0005] Spasmodic dysphonia has been treated with botulinum toxin type A. See Blitzer et al., Ann. Otol. Rhino. Laryngol, 1985, 94, 591-594. Lingual dystonia was treated with botulinum toxin type A according to Brin et al., Adv. Neurol. (1987) 50, 599-608. Finally, Cohen et al., Neurology (1987) 37 (Suppl. 1), 123-4, discloses the treatment of writer's cramp with botulinum toxin type A. [0006] The term botulinum toxin is a generic term embracing the family of toxins produced by the anae-robic bacterium Clostridium botulinum and, to date, seven immunologically distinct neurotoxins serotype have been identified. These have been given the designations A, B, C, D, E, F and G. For further information concerning the properties of the various botulinum toxins, reference is made to the article by Jankovic and Brin, The New England Journal of Medicine, No. 17, 1990, pp. 1186-1194, and to the review by Charles L. Hatheway in Chapter 1 of the book entitled Botulinum Neurotoxin and Tetanus Toxin , L. L. Simpson, Ed., published by Academic Press Inc. of San Diego, Calif., 1989, the disclosures in which are incorporated herein by reference. [0007] The neurotoxic component of botulinum toxin has a molecular weight of about 150 kilodaltons and is thought to comprise a short polypeptide chain of about 50 kD which is considered to be responsible for the toxic properties of the toxin, i.e., by interfering with the exocytosis of acetylcholine, by decreasing the frequency of acetylcholine release, and a larger polypeptide chain of about 100 kD which: is believed to be necessary to enable the toxin to bind to the pre-synaptic membrane. The “short” and “long” chains are linked together by means of a simple disulfid bridge. (It is noted that certain serotype of botulinum toxin, e.g., type E, may exist in the form of a single chain un-nicked protein, as opposed to a dichain. The single chain form is less active but may be converted to the corresponding dichain by nicking with a protease, e.g., trypsin. Both the single and the dichain are useful in the method of the present invention.) [0008] Immunotoxin conjugates of ricin and antibodies, which are characterized as having enhanced cytotoxi-city through improving cell surface affinity, are disclosed in European Patent Specification 0.129 434. The inventors note that botulinum may be utilized in place of ricin. [0009] Botulinum toxin is obtained commercially by establishing and crowing cultures of C. botulinum in a fermenter and then harvesting and purifying the fermented mixture in accordance with known techniques. [0010] Botulinum toxin type A, the toxin type generally utilized in treating neuromuscular conditions, is currently available commercially from several sources; for example, from Port Products Ltd. UK, under the trade name “DYSPORT,” and from Allergan, Inc., Irvine, Calif., under the trade name BOTOX®. [0011] It has been found, however, that some patients experience a loss of clinical responsiveness to botulinum toxin injections. One explanation for this action is that the patient has developed neutralizing antibodies or an immune response to, for example, botulinum toxin type A. Alternatively, the type of immune response may be different from just neutralizing antibodies. These include: (1) Allergic reaction where there is immediate local swelling, redness and itching. This may also be associated with general flu-like symptoms. (2) A delayed-type hypersensitivity manifested as swelling and redness at the injection site 48 to 72 hours after injection. (3) Or, a serum sickness-like response where the patient experiences flu-like symptoms. All of these immune-based reactions to type A dictate alternate serotype therapy to maintain clinical benefits. [0012] A further hypothesis may explain loss of clinical responsiveness to botulinum toxin injections. This does not include interaction of other medications which may interfere with the action of botulinum toxin (i.e., angiotensin converting enzyme inhibitor class of antihypertensives and other endopeptidase inhibitors, aminopyridines, acetylcholine esterase inhibitors, etc.). One possible explanation for the loss of responsiveness is an alteration in the neuronal binding of toxin to the presynaptic cholinergic nerve terminal. An alternation of gangliocides could reduce the binding efficacy of the toxin and thus reduce the amount of toxin internalized. Alternatively, an induction of proteases may cause an enhanced breakdown of the toxin either in the extracellular milieu or within the neuron. Finally, the neuron may change the amino acid composition of the target protein for the light chain of the toxin to reduce or eliminate its effect on the exocytotic mechanism. [0013] It is one object of the invention to provide novel treatments of neuromuscular disorders and conditions with botulinum toxin type A followed with treatments of botulinum toxin types B, C, D, E, F and G. SUMMARY OF THE INVENTION [0014] The present invention provides a method of treating a neuromuscular disorder or condition such as strabismus and other disorders of ocular motility, e.g., comitant and vertical strabismus, lateral rectus palsy, nystagmus, dysthyroid myopathy, etc.; dystonia, e.g., focal dystonias such as spasmodic torticollis, writer's cramp, blepharospasm, oromandibular dystonia and the symptoms thereof, e.g., bruxism, Wilson's disease, tardive dystonia, laryngeal dystonia etc.; other dystonias, e.g., tremor, tics, segmental myoclonus; spasms, such as spasticity due to chronic multiple sclerosis, spasticity resulting in abnormal bladder control, e.g., in patients with spinal cord injury, animus, back spasm, charley horse etc.; tension headaches; levator pelvic syndrome; spina bifida, tardive dyskinesia; Parkinson's and limb (focal) dystonia and stuttering, etc. of a patient, which method comprises administering to the patient suffering from said disorder or condition a therapeutically effective amount of a botulinum A followed with a neurotoxin of a different serotype, i.e., one selected from the group consisting of botulinum toxin types B, C, D, E, F and G. [0015] The clinical features of the above-listed neuromuscular disorders and conditions are described in Jankovic and Brin, cited above, and in Quinn, Disorders of Movement , Academic Press, 1989, all of which are incorporated herein by reference. [0016] The present invention further provides compositions of said botulinum toxins in a vehicle suitable for injection of said toxins into the appropriate region of the patient to be treated. Alterations of the vehicle and excipient may include materials designed to retain the injected toxin in the local area. [0017] The present invention further provides a method for treating neuromuscular disorders or conditions in which the patient experiences a loss of clinical response to an initial treatment of botulinum toxin. [0018] More specifically, a method in accordance with the present invention includes administering to the patient a therapeutically effective amount of botulinum toxin of a different serotype until the patient experiences loss of clinical response to the administered botulinum toxin and thereafter administering to the patient another botulinum toxin of the selected serotype, said another botulinum toxin being administered in therapeutically effect amounts. [0019] More particularly, the method in accordance with the present invention includes initial treatment with botulinum toxin type A followed by treatment with another botulinum toxin selected from the group consisting of types B, C, D, E and F. [0020] Alternatively, the initial treatment may be with botulinum toxin type B followed by another botulinum toxin serotype selected from the group consisting of types A, C, D, E and F. [0021] An alternative embodiment of the present invention includes the administration to a patient of a therapeutically effective amount of botulinum toxin of a selected serotype until the patient develops neutralizing antibodies and thereafter administration to the patient of another botulinum toxin of a different serotype, said another botulinum toxin being administered in a therapeutically effective amount. DETAILED DESCRIPTION [0022] The botulinum toxins used according to the present invention are botulinum toxin serotype A, B, C, D, E, F and G. [0023] Each serotype of botulinum toxin has been identified as immunologically different proteins through the use of specific antibodies. For example, if the antibody (antitoxin) recognizes, that is, neutralizes the biological activity of, for example, type A it will not recognize types B, C, D, E, F or G. [0024] While all of the botulinum toxins appear to be zinc endopeptidases, the mechanism of action of different serotypes, for example, A and E within the neuron appear to be different than that of type B. In addition, the neuronal surface “receptor” for the toxin appears to be different for the serotypes. [0025] The physiologic groups of Clostridium botulinum types are listed in Table I. TABLE I Physiologic Groups of Clostridium botulinum Phenotypically Toxin Glucose Phages Related Sero- Milk Fermen- & Clostridium Group Type Biochemistry Digest tation Lipase Plasmids (nontoxigenic) I A, B, F proteolytic saccharolytic + + + + C. sporogenes II B, E, F nonproteolytic saccharolytic − + + + psychotrophic III C, D nonproteolytic saccharolytic ± + + + C. novvi IV G proteolytic nonsaccharolytic + − − − C. subterminale These toxin types may be produced by selection from the appropriate physiologic group of Clostridium botulinum organisms. the organisms designated as Group I are usually referred to as proteolytic and produce botulinum toxins of types A, B and F. The organisms designated as Group II are saccharolytic and produce botulinum toxins of types B, E and F. The organisms designated as Group III produce only botulinum toxin types C and D and are distinguished from organisms of Groups I and II by the production of significant amounts of propionic acid. Group IV organisms only produce neurotoxin of type G. [0026] The production of any and all of the botulinum toxin types A, B, C, D, E, F and G are described in Chapter 1 of Botulinum Neurotoxin and Tetanus Toxin , cited above, and/or the references cited therein. Botulinum toxins types B, C, p, E, F and G are also available from various species of clostridia. Currently fourteen species of clostridia are considered pathogenic. [0027] Most of the pathogenic strains produce toxins which are responsible for the various pathological signs and symptoms. Organisms which produce botulinum toxins have been isolated from botulism outbreaks in humans (types A, B, E and F) and animals (types C and D). Their identities were described through the use of specific antitoxins (antibodies) developed against the earlier toxins. Type G toxin was found in soil and has low toxigenicity. However, it has been isolated from autopsy specimens, but thus far there has not been adequate evidence that type G botulism has occurred in humans. [0028] In general, four physiologic groups of C. botulinum are recognized (I, II, III, IV). The organisms capable of producing a serologically distinct toxin may come from more than one physiological group. For example, Type B and F toxins can be produced by strains from Group I or II. In addition, other strains of clostridial species ( C. baratii , type F; C. butyricum , type E; C. novyi , type C 1 or D) have been identified which can produce botulinum neurotoxins. [0029] Preferably, the toxin is administered by means of intramuscular injection directly into a spastic muscle, in the region of the neuromuscular junction, although alternative types of administration (e.g., subcutaneous injection), which can deliver the toxin directly to the affected muscle region, may be employed where appropriate. The toxin can be presented as a sterile pyrogen-free aqueous solution or dispersion and as a sterile powder for reconstitution into a sterile solution or dispersion. [0030] Where desired, tonicity adjusting agents such as sodium chloride, glycerol and various sugars can be added. Stabilizers such as human serum albumin may also be included. The formulation may be preserved by means of a suitable pharmaceutically acceptable preservative such as a paraben, although preferably it is unpreserved. [0031] It is preferred that the toxin is formulated in unit dosage form; for example, it can be provided as a sterile solution in a vial or as a vial or sachet containing a lyophilized powder for reconstituting a suitable vehicle such as water for injection. [0032] In one embodiment, the botulinum toxin is formulated in a solution containing saline and pasteurized human serum albumin, which stabilizes the toxin and minimizes loss through non-specific adsorption. The solution is sterile filtered (0.2 micron filter), filled into individual vials and then vacuum-dried to give a sterile lyophilized powder. In use, the powder can be reconstituted by the addition of sterile unpreserved normal saline (sodium chloride 0.9% for injection). [0033] The dose of toxin administered to the patient will depend upon the severity of the condition; e.g., the number of muscle groups requiring treatment, the age and size of the patient and the potency of the toxin. The potency of the toxin is expressed as a multiple of the LD 50 value for the mouse, one unit (U) of toxin being defined as being the equivalent amount of toxin that kills 50% of a group of 18 to 20 female Swiss-Webster mice, weighing 20 grams each. [0034] The dosages used in human therapeutic applications are roughly proportional to the mass of muscle being injected. Typically, the dose administered to the patient may be up to about 1,000 units; for example, up to about 500 units, and preferably in the range from about 80 to about 460 units per patient per treatment, although smaller of larger doses may be administered in appropriate circumstances. [0035] As the physicians become more familiar with the use of this product, the dose may be changed. In the botulinum toxin type A, available from Porton, DYSPORT, 1 nanogram (ng) contains 40 U. 1 ng of the botulinum toxin type A, available from Allergan, Inc., i.e., BOTOX®, contains 4 U. The potency of botulinum toxin and its long duration of action mean that doses will tend to be administered on an infrequent basis. [0036] Ultimately, however, both the quantity of toxin administered and the frequency of its administration will be at the discretion of the physician responsible for the treatment and will be commensurate with questions of safety and the effects produced by the toxin. [0037] The invention will now be illustrated by reference to the following nonlimiting examples. [0038] In each of the examples, the appropriate muscles of each patient are injected with sterile solutions containing the botulinum toxins. Total patient doses range from 80 U to 460 U. Before injecting any muscle group, careful consideration is given to the anatomy of the muscle group, the aim being to inject the area with the highest concentration of neuromuscular junctions, if known. Before injecting the muscle, the position of the needle in the muscle is confirmed by putting the muscle through its range of motion and observing the resultant motion of the needle end. General anaesthesia, local anaesthesia and sedation are used according to the age of the patient, the number of sites to be injected, and the particular needs of the patient. In accordance with the present invention, multiple injections are necessary to achieve the desired result, due to the patient's experiencing loss of clinical response to an initial treatment. Also, some injections, depending on the muscle to be injected, may require the use of fine, hollow, teflon-coated needles, guided by electromyography. [0039] Following injection, it is noted that there are no systemic or local side effects and none of the patients are found to develop extensive local hypotonicity. The majority of patients show an improvement in function both subjectively and when measured objectively. EXAMPLE 1 The Use of Botulinum Toxin Serotype A, B and F in the Treatment of Tardive Dyskinesia [0040] A patient, suffering from tardive dyskinesia resulting from the treatment with an antipsychotic drug, such as haloperidol, is treated with an effective amount of botulinum toxin type A by direct injection of such toxin into the muscles identified by the physician. After two to four days, the symptoms of tardive dyskinesia, i.e., orofacial dyskinesia, athetosis, dystonia, chorea, tics and facial grimacing, etc., are markedly reduced. Upon continued administration of the botulinum toxin type A, a loss of clinical response is noted. Thereafter, an effective amount of botulinum toxin type B is injected and the symptoms of tardive dyskinesia continue to be markedly reduced. EXAMPLE 1(a) [0041] The method of Example 1 is repeated, except that a patient suffering from tardive dyskinesia is injected with an effective amount of botulinum toxin type A, followed by injection of an effective amount of botulinum toxin type C. Similar results are obtained. EXAMPLE 1(b) [0042] The method of Example 1 is repeated, except that a patient suffering from tardive dyskinesia is injected with an effective amount of botulinum toxin type A, followed by injection of an effective amount of botulinum toxin type D. Similar results are obtained. EXAMPLE 1(c) [0043] The method of Example 1 is repeated, except that a patient suffering from tardive dyskinesia is injected with an effective amount of botulinum toxin type A, followed by injection of an effective amount of botulinum toxin type E. Similar results are obtained. EXAMPLE 1(d) [0044] The method of Example 1 is repeated, except that a patient suffering from tardive dyskinesia is injected with an effective amount of botulinum toxin type A, followed by injection of an effective amount of botulinum toxin type F. Similar results are obtained. EXAMPLE 2 Use of Botulinum Toxin in the Treatment of Spasmodic Torticollis [0045] A male, suffering from spasmodic torticollis, as manifested by spasmodic or tonic contractions of the neck musculature, producing stereotyped abnormal deviations of the head, the chin being rotated to one side, and the shoulder being elevated toward the side at which the head is rotated, is treated by injection with up to about 300 units, or more, of botulinum toxin type E, (having an activity of one to four days) in the dystonic neck muscles. After the symptoms are substantially alleviated and the patient is able to hold his head and shoulder in a normal position, the patient develops antibodies. Thereafter the patient is injected with botulinum toxin type B and the symptoms continue to be substantially alleviated. [0046] Although there has been hereinabove described a use of botulinum toxin serotype for treating neuromuscular disorders and conditions in accordance with the present invention, for the purpose of illustrating the manner in which the invention may be used to advantage, it should be appreciated that the invention is not limited thereto since many obvious modifications can be made, and it is intended to include within this invention any such modifications as will fall within the scope of the appended claims. Accordingly, any and all modifications, variations, or equivalent arrangements which may occur to those skilled in the art, should be considered to be within the scope of the present invention as defined in the appended claims.
A method of treating a patient suffering from a disease, disorder or condition includes the administration to the patient of a therapeutically effective amount of botulinum toxin of a selected serotype until the patient experiences loss of clinical response to the administered botulinum toxin and thereafter administering to the patient a therapeutically effective amount of another botulinum toxin of a different serotype.
0
CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of application Ser. No. 16,467 filed Mar. 1, 1979 now abandoned and it also relates to application Ser. No. 11,818 filed Feb. 13, 1979. BACKGROUND OF THE INVENTION The present invention relates to a method and device for conveying through a pipe a diphasic fluid of high free gas content. In the following, reference is made, by way of non limitative example, to the application of the invention to the complete recovery of petroleum effluents from an oil producing field. Petroleum effluents from an oil producing field often comprise a liquid and a gas phase. When the gas content reaches 10 to 20% of the liquid content, which corresponds to a high volumetric gas/oil ratio, it is not possible to increase the pressure of the gas-liquid mixture with presently available pumping equipments and it becomes necessary to separate the liquid phase from the gas phase and to process them separately. Such separation is achieved in one or more chambers by progressively reducing the pressure of the gas-liquid mixture to atmospheric pressure. Pumps are used to increase separately the liquid pressure to force it into the pipe or pipes provided therefore. The gas phase, which is separately processed, is either burnt in flares, i.e. without power recovery, or sometimes used to produce a part of the power required for actuating the oil field equipments or reinjected into the oil containing geological formations so as to increase the efficiency of oil recovery from these formations. The gas phase is rarely liquefied or conveyed through a separate line, since this would require very expensive investments which, up to now, appear little or not at all profitable. Not only the gas which is simultaneously produced with the liquid phase is practically never recovered, but separation of the gas and liquid phases requires a bulky equipment, which is a serious drawback in the case of offshore oil producing fields and requires a non negligible power consumption for increasing again the gas pressure which has been reduced during the gas-liquid separation. SUMMARY OF THE INVENTION An object of the present invention is to obviate or at least reduce these drawbacks by providing a method permitting the recovery of the greatest part of the petroleum effluents from an oil field, and the conveyance of both gas and liquid phases through one and the same pipe. The apparatus for carrying out the method according to the invention has the advantage of being compact, which facilitates its application to offshore oil production equipments. BRIEF DESCRIPTION OF THE DRAWING The invention will be better understood and all the advantages thereof made apparent from the following description illustrated by the accompanying drawings, wherein: FIG. 1 diagrammatically illustrates the whole device for carrying out the method according to the invention, FIG. 2 shows an embodiment of a device for increasing the gas pressure, FIG. 3 illustrates an embodiment of the mixing element, and FIGS. 4 to 8 illustrate an embodiment of the gas-liquid separator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 designates the pipe which is fed with a fraction of or with the entire oil effluent, under pressure, from the oil producing field, this effluent comprising a liquid and a gas phase in a volumetric gas/liquid ratio such that its pressure cannot be increased by using the presently available pumping means. This effluent is introduced into a gas-liquid separating element 2, which is preferably adapted to carry out this gas-liquid separation withuot any substantial pressure decrease. The separating element 2 delivers into a pipe 8 at least the liquid fraction of the petroleum effluent. In other words the separating element 2 is adapted to deliver a diphasic fluid whose gas/liquid volumetric ratio is at most equal to the maximum value of the volumetric ratio of the diphasic fluid mixture which can be processed by the pumping element 9 whose inlet orifice is connected to a separating element 2 by pipe 8. The pumping element 9 is adapted to increase the pressure of the diphasic fluid and to reduce the value of the volumetric ratio of this fluid preferably to a zero value, i.e. to a value for which the whole gas amount feeding pumping element 9 is dissolved in the liquid phase. Simultaneously the remaining fraction of the gas delivered by element 2 is transmitter through a pipe 10 to an element 11 capable of increasing the pressure of this gas to a value substantially equal to the pressure of the liquid delivered by pumping element 9. A fraction of the gas leaving element 11 is supplied through a pipe 7a to a mixing element 6 which also receives from pipe 12 the pressurized fluid delivered by pumping element 9. Mixing element 6 produces a diphasic fluid of a predetermined volumetric ratio, this fluid being transmitted through pipe 8a to a pumping element 9a similar to pumping element 9, i.e. increases the pressure of the diphasic fluid and reduces its gas/liquid volumetric ratio preferably to a zero value. If the whole amount of gas delivered by element 2 is not dissolved in the liquid, the residual gas amount is supplied through a pipe 10a to a pressure increasing element 11a and is thereafter admixed with the liquid delivered through pipe 12a by pumping element 9a, into a mixing element 6a whose outlet orifice is connected to another pumping element 9b, etc. When substantially all the gas is dissolved in the liquid, the resulting mixture is introduced into the (not shown) conveying pipe to be delivered to the utilization site, where vaporization of the dissolved gas can be obtained by decompression followed with the separation of this gas from the liquid. It is thus apparent that, in the case of petroleum effluents, the method according to the invention permits recovery of the gas fraction of these effluents, without requiring any additional conduit for conveying this gas fraction. Pumping elements, such as those designated by references 9, 9a, 9b . . . may be of any known type. However for building a compact apparatus which requires a minimum number of pumping elements, it will be preferable to use helico-axial pumps of the type described in the specification of French Pat. No. 2,333,139, capable of increasing the pressure of diphasic fluids having a higher volumetric gas/liquid ratio than the diphasic fluids processed by conventional pumping means. Elements such as 11, 11a . . . for increasing the gas pressure may be of any known type, for example compressors, or alternatively of the type described in my U.S. patent application Ser. No. 11,818, filed Feb. 13, 1979 entitled "Method and Device for Conveying an Essentially Gaseous Fluid through a Pipe." Briefly, as shown in FIG. 2, element 11 comprises a mixer 13 which receives the gas from pipe 10 and a sufficient amount of an auxiliary liquid which may be, for example, a fraction of the liquid delivered by the separating element 2 or which results from a chemical modification of the gas produced by separating element 2, this auxiliary liquid being introduced at 14. Mixer 13, which may, for example, be of the type illustrated in FIG. 4 of said U.S. patent application Ser. No. 11,818 delivers a diphasic fluid into a suitable pumping element 15, which may, for example, be a helico-axial pump, as above indicated. Optionally a separator 39 similar to separator 2, will permit recovery of the auxiliary liquid which may be recycled into mixer 13 through pipe 39a. Mixing element 6, 6a . . . may be of any known suitable type. A non limitative embodiment of this mixing element is illustrated by FIG. 3. This mixing element comprises pipes 16 and 17 which respectively connect pipes 7 and 12 to pipe 8a. In series with pipe 16 are connected an element 18 for measuring the volume (or flow rate) of liquid flowing through pipe 16, an element 19 creating an adjustable pressure drop, and optionally a pump 20 ensuring liquid circulation in this pipe and a buffer tank 4. In series with pipe 17 are connected an element 21 for measuring the volume (or flow rate) of gas flowing through pipe 17, an element 22 creating an adjustable pressure drop, and optionally a drain tank 23 wherein the liquid fraction which might be contained in the gas flow can be recovered by gravity, the bottom of this tank being connected to a drain pipe 24 having valve means 25 for partial or full closure or pipe 24, and optionally having a pump 26. Adjustment of the degree of opening of the obturating element or valve means 25 and control of the operation of pump 26 may be achieved automatically and sequentially, for example by a (not shown) device for sensing the liquid level in tank 23. In the embodiment illustrated in FIG. 3, pipe 24 connects tank 23 to liquid tank 4. Mixing element 6 is also provided with means diagrammatically indicated at 28, comprising, for example, two pressure sensors 29 and 30 which respectively measure the pressure in pipes 16 and 17 immediately before their connection to pipe 8a, these means 28 being adapted to deliver a signal representing the difference of the respective pressures measured by sensors 29 and 30. Elements 19 and 22 for creating pressure drops in the fluid are automatically set to the desired position by motor means diagrammatically shown at 19m and 22m. These motor means are energized by a control element 31 to which they are connected through transmission lines 32 and 33 respectively, this control circuit being responsive to the signal delivered by element 28 and transmitted through line 34. Mixing element 6 also comprises an element 27 creating an adjustable pressure drop in the gas flowing through pipe 10a and element 11a adapted to increase the gas pressure. Element 27 creating a pressure drop is automatically set to the desired position by motor means 27m actuated by a control element 35 which transmits a control signal through line 36 in relation with the signals delivered by the measuring elements 18 and 21 and transmitted through lines 37 and 38. During the operation, the liquid and gas are supplied to the mixing element 6 at substantially the same pressure P E and the diphasic fluid is delivered to pipe 8a at pressure P S which is generally slightly lower than P E . Element 28 delivers a signal representative of the difference between the respective pressures in pipes 16 and 17, immediately before their connection to pipe 8a. In dependence with this signal, control element 31 actuates motor means 19m and 22m which adjust elements 19 and 22 creating pressure drops, so that the pressure difference measured by element 28 is reduced and can be nullified. Simultaneously the flow rates (or volumes) of gas and liquid flowing through pipes 16 and 17 are measured by elements 18 and 21 respectively, delivering signals representative of these flow rates which are transmitted to control element 35. The latter generates a signal controlling the motor means 27m which adjusts element 27 creating a pressure drop, so that the ratio of the gas flow rate to the liquid flow rate remains substantially constant at a preselected value substantially equal to the ratio of the gas to liquid volume which should be obtained for conveying the diphasic fluid through the pipe. Thus when the ratio of the signals produced by the elements 21 and 18 is greater than a predetermined value corresponding to the value of the gas to liquid volumetric ratio which should be obtained for conveying the diphasic fluid through pipe 8a, control element 35 reduces the value of the pressure drop at 27 thereby increasing the gas flow rate through pipe 10a and consequently reducing the gas flow rate through pipe 17. On the contrary, when the ratio of the signals delivered by elements 21 and 18 is lower than the preselected value, the control element 35 increases the pressure drop at 27, thus reducing the gas flow rate through pipe 10a and correlatively increasing the gas flow rate in pipe 17. In other words the mixing element 6 equalizes the gas and liquid pressures before mixing, by monitoring the values of the dynamic pressure drops in the gas and liquid flows in relation with the pressure difference between these respective flows, and also controls the gas flow rate in dependence with the gas to liquid volumetric ratio. Measuring elements 18 and 21, for example flowmeters, elements 19, 22 and 27 for creating pressure drops, for example adjustable diaphragms, and pressure sensors 29 and 30 are well known to those of ordinary skill in the art and will therefore not be described here in detail, nor control elements 31 and 35. The drain tank 23, in series with pipe 17, makes it possible to recover by gravity the liquid fraction which may be contained in the gas flow. The gas-liquid separator designated by reference 2 in FIG. 1 may be of any known type. FIG. 4 shows, by way of example, a possible embodiment of this separator which essentially comprises an active element 40 for driving the fluid in rotation in a plane perpendicular to the direction of flow and a distributing element 41 which separately delivers the gas and the liquid. The active element 40 comprises a tubular body 42 housing a rotor 43 secured to the shaft 44 of a motor (not shown) for rotation. This rotor carries blades 45 which, as illustrated by FIGS. 5, 6 and 7, representing developed views of this rotor, may be of plane configuration and extend radially, inclined to the axis of rotation (FIG. 6) or curved thereto (FIG. 7) In the embodiments of FIGS. 6 and 7 the angle of inclination of blades 45 to the axis of rotation of rotor 43 is determined in relation to the axial rate of flow and in relation to the running speed of rotor 43. As a result of the action of the centrifugal force developed by the rotation, the liquid and gas phase are separated, the gas phase being maintained near the flow axis, while the liquid phase, of higher density is located at a distance from the rotor axis. The ends of rotor 43 may optionally be streamlined to substantially avoid any disturbance in the flow. Under these conditions, as shown in FIG. 4, the distributing element 41 is formed of two tubes 46 and 47, the smaller of these tubes collecting substantially only gas. These two tubes are coaxial over a portion of their length and are respectively connected to pipes 8 and 10 (FIG. 1). At the outlet of tube 46 is then collected the whole liquid phase to which is optionally added the portion of gas phase which has not been collected by tube 47. The diphasic fluid is introduced into the assembly 40-41 by a connecting pipe 48 connected to pipe 1. FIG. 8 diagrammatically illustrates another embodiment of the separating element of FIG. 1. This embodiment comprises a separator 2' delivering the whole gas phase of diphasic flow 1 to pipe 10, and the whole liquid phase to pipe 8'. The latter is connected to pipe 8 through a mixer 3 which simultaneously receives the gas delivered by separator 2' through pipe 5 and delivers a diphasic fluid of predetermined gas/liquid volumetric ratio. Changes may be made without departing from the scope of the present invention. The embodiment of element 40 illustrated by FIG. 4 comprises only one rotor, but it is also possible to use two distinct rotors rotated by two separate motors whose rotation speed can be continuously varied. Moreover it is possible to use a separator 2 of any known type which delivers to pipe 8 only the liquid phase of the flow from pipe 1. Pumping element 9, which may then be of any known type, increases the pressure of the liquid which then becomes under saturated with gas. A sufficient gas amount is fed from mixer 6 into this under-saturated liquid to obtain a saturated liquid in pipe 8a. A further pressure increase performed by pump 9a causes under-saturation of the liquid wherein a further gas amount can thus be dissolved. This fluid processing may be continued until complete dissolution of the gas in the liquid phase.
A method and device for conveying a diphasic fluid of high free gas content through a pipe includes separating a liquid of reduced free gas content from the diphasic fluid. The pressure of the separated liquid and the remaining gas are separately simultaneously increased to the same value and at least some of the increased pressure gas is remixed with the increased pressure liquid to obtain a new fluid of reduced free gas content. This new fluid is then introduced and conveyed through a pipe. Alternatively the steps of the method can be repeated before introducing the new fluid into the pipe for further reducing the free gas content thereof.
4
FIELD OF THE INVENTION [0001] The present invention relates to an arrangement for maintaining an EGR valve in the open position for an amount of time after the engine has stopped. BACKGROUND OF THE INVENTION [0002] Federal and State legislation require control of vehicle exhaust emissions. Oxides of Nitrogen (NOx) are one of the exhaust gas emissions that must be controlled. The higher the combustion temperature, the greater amount of NOx is produced. A system, referred to as the exhaust gas recirculation (EGR) system, has been developed to reduce combustion temperatures which thus reduces the amount of NOx emissions from the vehicle. A schematic of this system is shown in FIG. 1 . In the EGR system, a portion of the exhaust gas from the engine's exhaust manifold is recirculated back to the intake manifold where the exhaust gas is combined with incoming fresh air. The mixture of exhaust gas and fresh air are then compressed and ignited in the cylinder. This results in a lower combustion temperature and a reduction in NOx that is emitted from a vehicle's exhaust system. [0003] Referring to FIG. 1 , an EGR system 10 comprises of an EGR valve 12 that controls the flow of exhaust gas to the intake manifold. Space Conduits 14 , 16 , 18 provide the interconnection between an exhaust manifold 20 , the EGR valve 12 , and an intake manifold 22 . The system shown uses an electrically controlled EGR valve 12 . Thus, an engine control unit (ECU) 24 provides a signal that controls the open and closing of the EGR valve. As the EGR valve 12 opens and closes, the flow rate of exhaust gas to the intake manifold increases and decreases respectfully. It is also typical to have a throttle valve 26 to control airflow into the intake manifold and an exhaust gas cooler 28 to reduce temperature of recirculated exhaust gas prior to being mixed with the fresh air. [0004] The required EGR valve 12 flow rate of recirculating exhaust gas is dependent upon several factors that include, but are not limited to, the displacement of the engine, and the pressure differential between the exhaust system and the intake system. Operating force of the EGR system is also a factor used in the selection criteria for the type of actuator used for the EGR valve. Higher flow rates require larger valves with greater area and higher operating forces. Lower pressure differential between the exhaust and intake manifold requires larger valves to achieve the desired flow rate. Furthermore, debris in the exhaust gas accumulates on the valve components and causes the valve components to stick to one another or restricts movement if sufficient operating force is not available to move the valve components once the debris has stuck to the valve components. [0005] During normal operation of diesel engines the EGR valve poppet often becomes stuck to a valve seat when the EGR valve poppet is in the closed position. This condition renders the EGR valve inoperable. This is caused by excessive build up of exhaust gas debris in the EGR valve. This typically occurs after the engine is shut down and the EGR valve is in the closed position or the EGR valve poppet is seated on the valve seat. For example, EGR systems that run with cooled exhaust tend to produce a moist vapor like (lacquer) contamination, until the engine warms up, which builds up on the valve poppet and valve seat as exhaust gas flows past them as described in the previous paragraphs. Moreover, the lacquer contamination combines with a powdery (soot) type of contamination that is present in the exhaust gas at elevated (greater than 160° C.) exhaust gas temperatures. When the valve is commanded to the closed position the lacquer, soot, or a combination of the two, cures or hardens when the engine is shut off and causes a “bond” between the valve seat and poppet. This often happens after then engine is shut down for a duration of time such as 20 minutes or greater. When the engine is started again and the EGR valve is commanded to open, and the “bond” that has occurred prevents the valve from opening when there is insufficient force and or torque available from the EGR valve to overcome the bonded sticking force. [0006] Therefore it is desirable to develop an EGR valve, wherein the EGR valve poppet is not seated on the EGR valve seat when the engine is shut down. Thus, the EGR valve design prevents the EGR poppet valve from sticking to the valve seat, thereby increasing product robustness and prolonging product life. The following paragraphs and figures describe the application and use of an EGR valve with features that locate the poppet in a resting position when the valve is not in use so that at least a portion of the poppet valve is not contacting the valve seat. SUMMARY OF THE INVENTION [0007] The present invention is directed to a mechanism for preventing a poppet valve in an exhaust gas recirculation (EGR) valve assembly in a motor vehicle from sticking to a valve seat resulting in the EGR valve being inoperable. The EGR valve assembly includes an EGR valve body having an inlet port and an outlet port with the valve body defining a pass through for fluid flow between the inlet port and the outlet port. A valve seat is disposed between the inlet port and outlet port and has an aperture positioned in the path of fluid flow. A valve stem is positioned in the valve body and has a poppet valve member disposed on the end of the valve stem. The valve stem is configured to slide axially along its longitudinal axis to bring the poppet valve in contact with the valve seat and to move the poppet valve member away from the valve seat to place the valve mechanism in a position where at least a portion of the poppet valve does not contact the valve seat. In a preferred embodiment, the poppet valve is fully disconnected from the valve seat when in the resting position. An actuator is connected to the valve stem and causes the valve stem to slide axially along its longitudinal axis. A pinion gear is connected to the actuator and is in meshed engagement with a second gear that is mounted to the valve shaft. A default position arrangement is operably configured with the valve stem for placing the poppet valve in a resting position where at least a potion of the poppet valve does not contact the seat when the actuator is idle from its normal operation. [0008] The default position arrangement takes several different forms. For example, the default position arrangement is a light load return spring that acts on the valve stem to hold the poppet valve at the resting position away from the valve seat when the actuator is energized and then suddenly becomes de-energized. The default position arrangement is also a reverse full open spring that acts on the valve stem by applying torque to the spur gear in order to place the poppet valve in the resting position when the actuator is de-energized. In an alternate embodiment, the default position arrangement is also configured so that a small amount of electrical current is applied to the actuator in order to hold the poppet valve in the resting position when the actuator is shut down from its normal operation. Lastly, the default position arrangement includes a drive pin and ramp assembly having a holding feature so that when the actuator opens the poppet valve to a maximum position and becomes de-energized the holding feature holds the poppet valve open until the actuator applies torque to drive the poppet valve which moves the poppet valve to the closed position. [0009] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS [0010] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: [0011] FIG. 1 is a schematic diagram of a combustion engine system having an EGR valve incorporated thereon; [0012] FIG. 2 is a partial cross-section perspective side view of an EGR valve body having an actuator connected thereon; [0013] FIG. 3 a is a cross-sectional side view of a sub-assembly with the stem, shield, and poppet valve members in a closed position; [0014] FIG. 3 b is a cross-sectional side view of the sub-assembly with the stem, shield, and poppet valve members in an open position; [0015] FIG. 4 is a cross-sectional perspective view of an EGR valve body with an actuator having a torsion spring acting thereon; [0016] FIG. 5 is a cross-sectional perspective view of an EGR valve having a reverse torsion spring; [0017] FIG. 6 is a partial cross-section view of the valve seat with the sub-assembly; [0018] FIG. 7 is an overhead perspective view of the valve body and spur gear having a default position spring; and [0019] FIG. 8 is a perspective view of the EGR valve seat having a wedge ramp feature. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0020] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. [0021] Referring to FIG. 2 , an exhaust gas recirculation (EGR) valve assembly is generally shown at 30 . The actuator 100 is connected to a valve body assembly 36 through the use of fasteners 32 ; a gasket 38 is used to prevent leakage from occurring between the actuator 100 and the valve body assembly 36 . Fasteners 32 are used to locate the actuator 100 and the valve body assembly 36 . The EGR valve 30 is typically mounted to the engine's intake manifold by mounting bolts. The exhaust gas flows from inlet 92 , into chamber 94 , through valve seat 90 , by poppet valve 76 , into cavity 98 , and to outlet 96 when poppet valve 76 is unseated from valve seat 90 and there is a sufficient pressure differential between the inlet 92 and outlet 96 . In a preferred embodiment, the pressure in chamber 94 is positive. However, in an alternate embodiment, the pressure in chamber 94 is negative or fluctuates between a positive and negative pressure. [0022] FIG. 3 a and 3 b show the open and closed positions of the poppet valve 76 . More specifically, FIG. 3 a shows the closed position of the poppet valve 76 , and FIG. 3 b shows the open position of the poppet valve 76 . FIGS. 3 a and 3 b also show a deflector 102 connected to poppet valve 76 , which is used for deflecting away debris from the valve stem 74 . [0023] Referring to FIGS. 4 , 5 , and 6 , EGR valve assembly 30 has a housing 40 designed to accept an electrical connector 42 . In a preferred embodiment, a motor 44 , and an integral bracket 64 are secured by screws 46 to the housing 40 . The motor 44 is electrically connected to the electrical connector 42 , such that the motor 44 draws electrical current when in use. [0024] A bushing 48 and roller bearing 50 are fit into housing 40 . A gear 52 is fastened to shaft 54 . A torsion spring 56 and spring bushing 58 are placed over the shaft 54 . The shaft 54 extends through the bearing 50 and bushing 58 and is retained by a clip 60 . A gear 62 , fastened to a motor shaft 88 , engages gear 52 . Thus, gear 52 rotates with respect to gear 62 . The torsion spring 56 engages features on the housing 40 and gear 52 to provide torsional force that acts upon shaft 54 . [0025] A valve subassembly 68 consists of retainer housing 78 , bearing guide 66 , valve stem 74 , pin 70 , bearings 72 , and poppet valve 76 . Bearing 72 is fastened at one end of pin 70 . The pin 70 is placed through an engagement hole at one end of valve stem 74 . A second bearing is fastened to the opposite end of the pin (not shown). The valve stem 74 is installed by inserting it through the integral bearing section of bearing guide 66 . The valve stem 74 is inserted until the bearing 72 contacts integral slotted guide ramp portion 84 of the bearing guide 66 . The slotted guide ramp portion 84 has ramp surfaces 86 that contain and guide the bearing 72 when torque is applied to the pin 70 which forces the valve stem 74 to rotate about its longitudinal axis. The valve stem 74 moves in an axial direction as the bearing 72 moves along the slotted guide ramp portion 84 . The slotted guide ramp portion surfaces 86 has a defined slope that causes the desired axial movement of the valve stem 74 . The slotted guide ramp portion 84 is shown in more detail in FIGS. 4 , 6 , and 8 . In a preferred embodiment, the slotted guide ramp portion 84 is machined into a one-piece bearing guide 66 , as shown in FIG. 4 . In an alternate embodiment, the slotted guide ramp portion 84 is made in more than one-piece to accommodate various assembly methods. For example, the slotted guide ramp portion 84 has an upper and lower section, each having a portion of either slotted guide ramp. [0026] In a preferred embodiment, a poppet valve 76 is installed and retained on valve stem 74 by suitable means, such as, but not limited to, swaging. In an alternative embodiment, the poppet valve 76 is keyed to the shaft in a manner that will cause the poppet valve 76 to rotate with the shaft. [0027] Also in a preferred embodiment, the bearing guide 66 of valve sub-assembly 68 is secured in the retainer body 78 by suitable means, such as, but not limited to, swaging as shown in FIG. 4 . The actuator 100 and valve sub-assembly 68 are aligned by suitable locating features and are held together by fasteners (not shown). Gear 52 also has an integral fork feature 85 that engages pin 70 . When the engine control unit provides a suitable control signal to the motor 44 , it causes gears 62 and 52 to rotate. The integral fork feature 85 causes pin 70 to move bearing 72 along ramp 86 resulting in rotary-axial movement of the valve stem 74 and poppet valve 76 . The control signal causes the motor 44 and gears 62 and 52 to rotate in either a clockwise or counter-clockwise direction, therefore, the valve stem 74 and poppet valve 76 are capable of moving in either direction. [0028] Also, the EGR valve assembly 30 has a default position arrangement, which has several embodiments described below. The default position arrangement places the poppet valve 76 in any predetermined position besides the closed position. Preferably, when the poppet valve 76 is in the resting position the poppet valve 76 does not contact the valve seat 90 . However, the resting position can be a position where the poppet valve 76 is only partially contacting the valve seat 90 when compared to the contact between the poppet valve 76 and valve seat 90 when the poppet valve 76 is in the closed position. [0029] The first embodiment of the present invention is comprised of a low-torque torsion spring 56 , which is placed over a shaft along with the spring bushing 58 . In this embodiment, the torsion spring 56 engages the housing and the gear 52 in order to provide torsion force against the shaft 54 . Thus, the torsion spring 56 is configured so that after the poppet valve 76 is opened to its fully open position, and power to the motor 44 is cut off, the torsion exerted by the torsion spring 56 is not forceful enough to overcome the system friction required to bring the poppet valve 76 back into contact with the valve seat 90 or prevents the poppet valve 76 from fully contacting the valve seat 90 . The poppet valve 76 being prevented from being placed in the closed position while the EGR valve assembly 30 is not in operation prevents the poppet valve 76 from sticking to valve seat 90 as the system cools, and any debris build-up in the system cools as well. [0030] A second embodiment of the present invention comprises having the torsion spring 56 configured to bias the poppet valve 76 toward the open position. This is achieved by using a torsion spring 56 that has a winding direction opposite that of a spring that biases poppet valve 76 in the closed position. When power to the motor 44 is cut off, and no load besides the load from the torsion spring 56 is being applied to poppet valve 76 , poppet valve 76 is held in an open position, until power is supplied to the motor 44 . When the motor 44 is actuated, the bias force of the torsion spring 56 is overcome and the poppet valve 76 closes. This embodiment can be achieved by using a slotted guide ramp portion 86 geometry that is reversed rather than a torsion spring 56 that has a winding direction that is reversed. [0031] In a third embodiment of the present invention, the torsion spring 56 is configured to provide a default position for the poppet valve 76 . This default, or intermediate, position of gear 52 is shown in FIG. 7 . The torsion spring 56 geometry and the actuator housing 40 geometry are designed such that when the motor 44 is un-powered, the poppet valve 76 is located in a default or intermediate position that is a specified distance off of the valve seat 90 . This is accomplished by using a torsion spring 56 that has a sufficient amount of force to move the poppet valve 76 to the default position. [0032] In a fourth embodiment of the present invention, the poppet valve 76 is electronically placed in the open position or in a position where at least part of the poppet valve 76 is not contacting the valve seat 90 . In this embodiment, a small amount of electrical current is used to power the poppet valve 76 to an unseated position when the engine is shut down. The small amount of electrical current flows through the actuator 100 keeping the poppet valve 76 in the open position or prevents it from fully contacting the valve seat 90 for a predetermined period of time. Typically, the predetermined amount of time is a time period that is long enough for the contamination to cure or harden; thereby, preventing the “bonding” of the poppet valve 76 to the valve seat 90 . No geometry or hardware changes are required for this method, but the Engine Control Module (ECM) has to be altered to provide electrical power in a shutdown mode without draining the vehicle battery. [0033] The fifth embodiment of the present invention is shown in FIG. 8 . In this embodiment, a holding feature 82 is added to the bearing slotted guide ramp portion 84 or cam mechanism such that the poppet valve 76 is electrically powered past the maximum allowable flow position before engine shutdown. Therefore, the poppet valve 76 remains above the holding feature 82 in a full stroke unseated position until the motor 44 direction is reversed and electrical current is applied to power the drive bearing 72 back over the holding feature 82 onto the active part of the ramps 86 . Examples of the holding feature 86 are, but not limited to, a wedge, an even surface, a bump, or a detent area, where the bearing 72 contacts the holding feature 86 when moving along the slotted guide ramp member 86 . Thus, a force is applied to the bearing 72 in order for bearing 72 to pass back over the holding feature 86 , where the poppet valve 76 moves towards the closed position. [0034] All five of the aforementioned embodiments keep the poppet valve 76 and valve seat 90 out of contact with each other or partially out of contact with each other while the debris is curing or hardening which would ultimately cause the poppet valve 76 to bond to the valve seat 90 making the EGR valve assembly 30 inoperable. In a preferred embodiment, the embodiments do not allow the poppet valve 76 from contacting the valve seat 90 during the curing process to ensure there is no bonding between the two parts. Alternatively, the above embodiments, allow the poppet valve 76 to partially contact the valve seat 90 , which reduces the amount of surface area of the poppet valve 76 and the valve seat 90 that bond together. Thus, the bonding that does occur is overcome by the torque applied to the poppet valve 76 , which is a lesser torque than needed to separate the poppet valve 76 from the valve seat 90 when the poppet valve 76 is in the closed position during the curing process. [0035] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.
During normal operation of diesel engines the EGR valve poppet often becomes stuck to the valve seat in the closed position, due to excessive build up of exhaust gas debris, which renders the valve inoperable. This usually occurs after the engine is shut down and the valve is seated. Features, which locate the valve poppet in an unseated position when not in use, are implemented into the EGR valve design to prevent this sticking from occurring, thereby increasing product robustness and prolonging product life.
5
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 61/039,470, filed Mar. 26, 2008, the entire contents of which are incorporated herein by reference. BACKGROUND [0002] Gas turbines are often located at synthesis gas production sites. It is typical for the fuel for both the gas turbine and the hydrocarbon containing reactant fed for the synthesis gas production to be natural gas. Where such installations exist, the gas turbines are not normally thermally linked to the synthesis gas production. In integrated gasification combined cycles, however, the gas turbine and the synthesis gas production are both thermally and operationally linked in that the fuel to the gas turbine is the synthesis gas and the synthesis gas is reheated through heat transfer with the synthesis gas stream being produced. [0003] In the present invention the gas turbine is combined with the SMR to generate power, hydrogen, and steam. This cogeneration scheme improves overall thermal efficiency of the process. It reduces the amount of by-product steam. The hydrogen generation is done in an exchanger type of reactor that is much more compact as compared to a conventional SMR furnace SUMMARY [0004] A process for the integration of power generation and an SMR, including introducing a combustion air stream into a compressor, thereby producing a compressed air stream. The compressed air stream is then introduced, along with a combustor feed gas stream into a first combustor, thereby producing a first exhaust gas stream. The first exhaust gas stream is then introduced into the shell-side of an SMR, thereby providing the heat for the reforming reaction, and generating a syngas stream and a second exhaust gas stream. The second exhaust gas stream is introduced, along with a secondary fuel stream, into a second combustor, thereby producing a third exhaust gas stream. The third exhaust gas stream is then introduced into an expander, thereby producing power output and a fourth exhaust gas stream. BRIEF DESCRIPTION OF DRAWINGS [0005] The invention may be understood by reference to the following description taken in conjunction with the accompanying drawings, and in which: [0006] FIG. 1 is a schematic representation of one embodiment of the present invention. [0007] FIG. 2 is a schematic representation of another embodiment of the present invention. [0008] FIG. 3 is a schematic representation of one embodiment of the present invention. [0009] FIG. 4 is a schematic representation of another embodiment of the present invention. [0010] FIGS. 1 a - 4 a are schematic representations of another embodiment of the present inventions, as described in FIGS. 1-4 . DESCRIPTION OF PREFERRED EMBODIMENTS [0011] Turning now to FIG. 1 , combined SMR and cogeneration system 100 is provided. Combustion air stream 101 is introduced to air compressor 102 , where it is compressed and exits as compressed air stream 103 . Natural gas stream 104 introduced into natural gas pre-heater 105 , where it exits as heated natural gas stream 106 . Natural gas stream 104 may be purified if necessary. Heated natural gas stream 106 is divided into at least two portions, combustor feed gas stream 107 and SMR feed gas stream 108 . Combustor feed gas stream 107 is combined with compressed air stream 103 in first combustor 109 , where it is combusted, thereby generating first exhaust gas stream 110 . First exhaust gas stream 110 may have a temperature of between about 2000 F. and about 2200 F. Steam stream 111 , is combined with SMR feed gas stream 108 , to form combined feed stream 112 . Combined feed stream 112 is further preheated in a mixed feed preheater section of waste heat boiler 128 (shown in FIG. 1 a ). Preheated combined feed stream 124 is introduced into SMR 113 , where it exits as syngas stream 119 . Syngas stream 119 may have a temperature of between about 1200 F. and about 1600 F. In one embodiment, SMR 113 may be of the type known as an exchanger type, which has no burners to supplement the heat content of first exhaust gas stream 110 . In another embodiment, SMR 113 may have burners (not shown) to supplement the heat content of first exhaust gas stream 110 , as needed. First exhaust gas stream 110 is introduced into the shell-side of SMR 113 , where it provides the heat required for the steam reforming process, then exiting as second exhaust gas stream 114 . Syngas stream 119 is introduced into filter 120 , where it is separated into hot hydrogen product stream 121 and secondary fuel stream 122 . Filter 120 may be a ceramic or metallic separator. Secondary fuel stream 122 may contain one or more of the following, unconverted methane, unrecovered H2, CO, CO2, and unused steam. The metallic separator may utilize palladium. Second exhaust gas stream 114 is combined with secondary fuel stream 122 in second combustor 115 where it is combusted, thereby generating third exhaust gas stream 116 . Third exhaust gas stream 116 is introduced into expander 117 , where it is expanded and exits as fourth exhaust gas stream 118 . Fourth exhaust gas stream 118 may have a temperature of between about 800 F. and about 1100 F. Fourth exhaust gas stream 118 is used for preheating mixed feed stream 112 , and for generating steam. Boiler feed water stream 125 is introduced into waste heat boiler 128 , wherein it is heated, vaporized, and superheated into steam stream 126 . Steam stream 126 may be used to feed the SMR (stream 111 ), with any remaining steam being available for exportation, or for power generation in a steam turbine (not shown). [0012] Hot hydrogen product stream 121 is then introduced into natural gas pre-heater 105 , where indirectly exchanges heat with natural gas stream 104 , exiting as 15 cooled hydrogen product stream 123 . In another embodiment, the heat from hot hydrogen stream 121 may be used for preheating BFW. [0013] In one embodiment, air compressor 102 and expander 117 may be mechanically attached. In another embodiment, the power required for air compressor 102 is at least partially provided by the power generated by expander 117 . In another embodiment, the power required for air compressor 102 is completely provided by the power generated by expander 117 . [0014] The above described process can be optimized by one skilled in the art, depending upon the particular power, steam and hydrogen products requirements. At least the following variables are available for optimization, with the skilled artisan recognizing that other aspects of the proposed invention may also be manipulated to yield further optimized results. [0015] The amount of natural gas that is sent to SMR (stream 108 ) may be varied to optimize the system. This parameter affects the amount of heat that is used for reforming. The amount of hydrogen that is made in SMR increases when more natural gas is reformed. However increasing the natural gas into the SMR reduces the amount of power that is produced in expander 117 , as the exhaust gas temperature (streams 114 and 116 ) is reduced. [0016] The steam to natural gas ratio may be varied to optimize the system. If the steam to natural gas ratio is increased, the amount of hydrogen that is produced increases. The excess steam that is not used in the reforming of methane will ultimately be sent to expander 117 , which will result in increased power production. The desired minimum molar ratio of steam to methane is about 2.0. [0017] SMR 113 contains a catalyst to assist the steam reforming of methane. The catalyst may be in the shape of pellets, granular, tablets etc. The catalyst can also be in the form of a coated monolith or coated tube surface. The catalysts using nickel or noble metals are commercially available. [0018] Hot hydrogen product stream 121 , as permeate from the filter 120 is hot and may be at low pressure of less than 50 psig. Heat is recovered from this stream and the product hydrogen is compressed to desired pressure. [0019] The use of heat for hydrogen production improves the efficiency of power generation and hydrogen generation. [0020] This processing scheme differs from the prior art in a number of respects. First the instant process uses higher level heat, upstream of expander 117 , for reforming. Second the hot gases that are used in the reforming exchanger are at high pressure, thereby reducing the size of the reforming exchanger. Third the proposed process recovers hydrogen from the reformed gas mixture. Fourth the proposed process removes hydrogen from the gas mixture at elevated temperature, thereby allowing the use of hot residue gas fuel. [0021] Turning now to FIG. 2 , combined SMR and cogeneration system 200 is provided. Combustion air stream 201 is introduced to air compressor 202 , where it is compressed and exits as compressed air stream 203 . Natural gas stream 204 introduced into natural gas pre-heater 205 , where it exits as heated natural gas stream 206 . Natural gas stream 204 may be purified if necessary. Heated natural gas stream 206 is divided into at least two portions, combustor feed gas stream 207 and SMR feed gas stream 208 . Combustor feed gas stream 207 is combined with compressed air stream 203 in combustor 209 , where it is combusted, thereby generating first exhaust gas stream 210 . First exhaust gas stream 210 is introduced into expander 217 , where it is expanded and exits as second exhaust gas stream 221 . Steam stream 211 , is combined with SMR feed gas stream 208 , to form combined feed stream 212 . Combined feed stream 212 is further preheated in a mixed feed preheater section of waste heat boiler 225 (shown in FIG. 2 a ). Preheated combined feed stream 226 is then introduced into SMR 213 , where it exits as syngas stream 215 . Second exhaust gas stream 221 is introduced into the shell-side of SMR 213 , where it provides the heat required for the steam reforming process, then exiting as third exhaust gas stream 214 . Third exhaust gas stream 214 is used for preheating mixed feed stream 212 , and for generating steam. Boiler feed water stream 222 is introduced into waste heat boiler 225 , wherein it is heated, vaporized, and superheated into steam stream 223 . Steam stream 223 may be used to feed the SMR (stream 211 ), with any remaining steam being available for exportation, or for power generation in a steam turbine (not shown). [0022] In one embodiment, SMR 213 may be of the type known as an exchanger type, which has no burners to supplement the heat content of first exhaust gas stream 203 . In another embodiment, SMR 213 may have burners (not shown) to supplement the heat content of first exhaust gas stream 221 , as needed. Syngas stream 215 is introduced into filter 216 , where it is separated into hot hydrogen product stream 217 and secondary fuel stream 218 . Filter 216 may be a ceramic or metallic separator. Secondary fuel stream 218 may contain one or more of the following, unconverted methane, unrecovered H2, CO, CO2, and unused steam. The metallic separator may utilize palladium. Hot hydrogen product stream 217 is then introduced into natural gas pre-heater 205 , where indirectly exchanges heat with natural gas stream 204 , exiting as cooled hydrogen product stream 220 . [0023] In one embodiment, air compressor 202 and expander 217 may be mechanically attached in another embodiment, the power required for air compressor 202 is at least partially provided by the power generated by expander 217 . In another embodiment, the power required for air compressor 202 is completely provided by the power generated by expander 217 . In one embodiment, third exhaust gas stream 214 may be used for preheating natural gas, preheating a mixed feed to the SMR, for generating steam, or any combination thereof. In one embodiment, the steam that is generated is used to feed the SMR, with any remaining steam being available for exportation, or for power generation in a steam turbine (not shown). [0024] Turning now to FIG. 3 , combined SMR and cogeneration system 300 is provided. Combustion air stream 301 is introduced to air compressor 302 , where it is compressed and exits as compressed air stream 303 . Natural gas stream 304 introduced into natural gas pre-heater 305 , where it exits as heated natural gas stream 306 . Natural gas stream 304 may be purified if necessary. Heated natural gas stream 306 is divided into at least two portions, combustor feed gas stream 307 and SMR feed gas stream 308 . Combustor feed gas stream 307 is combined with compressed air stream 303 in first combustor 309 , where it is combusted, thereby generating first exhaust gas stream 310 . First exhaust gas stream 310 is introduced into first expander 331 , where it is expanded and exits as second exhaust gas stream 332 . Steam stream 311 , is combined with SMR feed gas stream 308 , to form combined feed stream 312 . Combined feed stream 312 is further preheated in a mixed feed preheater section of waste heat boiler 336 (shown in FIG. 3 a ). Preheated combined feed stream 337 is introduced into SMR 313 , where it exits as syngas stream 315 . In one embodiment, SMR 313 may be of the type known as an exchanger type, which has no burners to supplement the heat content of fourth exhaust gas stream 323 . In another embodiment, SMR 313 may have burners (not shown) to supplement the heat content of fourth exhaust gas stream 323 , as needed. Fourth exhaust gas stream 323 is introduced into the shell-side of SMR 313 , where it provides the heat required for the steam reforming process, then exiting as fifth exhaust gas stream 314 . Fifth exhaust gas stream 314 is used for preheating mixed feed stream 312 , and for generating steam. Boiler feed water stream 333 is introduced into waste heat boiler 336 , wherein it is heated, vaporized, and superheated into steam stream 334 . Steam stream 334 may be used to feed the SMR (stream 311 ), with any remaining steam being available for exportation, or for power generation in a steam turbine (not shown). [0025] Syngas stream 315 is introduced into filter 316 , where it is separated into hot hydrogen product stream 317 and secondary fuel stream 318 . Filter 316 may be a ceramic or metallic separator. Secondary fuel stream 318 may contain one or more of the following, unconverted methane, unrecovered H2, CO, CO2, and unused steam. The metallic separator may utilize palladium. Secondary fuel stream 318 is introduced into second expander 319 , where it is expanded and exits as expanded secondary fuel gas stream 320 . Second exhaust gas stream 332 is combined with expanded secondary fuel stream 320 in second combustor 322 where it is combusted, thereby generating fourth exhaust gas stream 323 . Hot hydrogen product stream 317 is then introduced into natural gas pre-heater 305 , where indirectly exchanges heat with natural gas stream 304 , exiting as cooled hydrogen product stream 324 . [0026] In one embodiment, air compressor 302 and first expander 331 may be mechanically attached. In another embodiment, the power required for air compressor 302 is at least partially provided by the power generated by at least one of first expander 331 and second expander 319 . In another embodiment, the power required for air compressor 302 is completely provided by the power generated by expander 331 . In one embodiment, fifth exhaust gas stream 314 may be used for preheating natural gas, preheating a mixed feed to the SMR, for generating steam, or any combination thereof. In one embodiment, the steam that is generated is used to feed the SMR, with any remaining steam being available for exportation, or for power generation in a steam turbine (not shown). [0027] Turning now to FIG. 4 , combined SMR and cogeneration system 400 is provided. Combustion air stream 401 is introduced to air compressor 402 , where it is compressed and exits as compressed air stream 403 . Natural gas stream 404 introduced into natural gas pre-heater 405 , where it exits as heated natural gas stream 406 . Natural gas stream 404 may be purified if necessary. Heated natural gas stream 406 is divided into at least two portions, combustor feed gas stream 407 and SMR feed gas stream 408 . Combustor feed gas stream 407 is combined with compressed air stream 403 in first combustor 409 , where it is combusted, thereby generating first exhaust gas stream 410 . First exhaust gas stream 410 is introduced into expander 420 , where it is expanded and exits as second exhaust gas stream 421 . Steam stream 411 , is combined with SMR feed gas stream 408 , to form combined feed stream 412 . Combined feed stream 412 is further preheated in a mixed feed preheater section of waste heat boiler 428 (shown in FIG. 4 a ). Preheated combined feed stream 429 is introduced into SMR 413 , where it exits as syngas stream 415 . In one embodiment, SMR 413 may be of the type known as an exchanger type, which has no burners to supplement the heat content of fourth exhaust gas stream 424 . In another embodiment, SMR 413 may have burners (not shown) to supplement the heat content of fourth exhaust gas stream 424 , as needed. Fourth exhaust gas stream 424 is introduced into the shell-side of SMR 413 , where it provides the heat required for the steam reforming process, then exiting as fifth exhaust gas stream 414 . Fifth exhaust gas stream 414 is used for preheating mixed feed stream 412 , and for generating steam. Boiler feed water stream 425 is introduced into waste heat boiler 428 , wherein it is heated, vaporized, and superheated into steam stream 426 . Steam stream 426 may be used to feed the SMR (stream 411 ), with any remaining steam being available for exportation, or for power generation in a steam turbine (not shown). [0028] Syngas stream 415 is introduced into natural gas pre-heater 405 , where indirectly exchanges heat with natural gas stream 404 , exiting as cooled syngas stream 416 . In one embodiment, cooled syngas stream 416 is at approximately ambient temperature. In another embodiment, cooled syngas stream 416 is at approximately 10 degrees warmer than ambient temperature. Cooled syngas stream 416 is introduced into PSA 417 , where it is separated into hydrogen product stream 418 and secondary fuel stream 419 . Secondary fuel stream 419 may contain one or more of the following, unconverted methane, unrecovered H2, CO, CO2, and unused steam. Secondary fuel stream 419 may be at a pressure of between about 2 psig and about 20 psig. Second exhaust gas stream 421 is combined with secondary fuel stream 419 in second combustor 423 where it is combusted, thereby generating fourth exhaust gas stream 424 . [0029] In one embodiment, air compressor 402 and expander 420 may be mechanically attached. In another embodiment, the power required for air compressor 402 is at least partially provided by the power generated by expander 420 . In another embodiment, the power required for air compressor 402 is completely provided by the power generated by expander 420 . In one embodiment, fifth exhaust gas stream 414 may be used for preheating natural gas, preheating a mixed feed to the SMR, for generating steam, or any combination thereof. In one embodiment, the steam that is generated is used to feed the SMR, with any remaining steam being available for exportation, or for power generation in a steam turbine (not shown).
A process for the integration of power generation and an SMR, including introducing a combustion air stream into a compressor, thereby producing a compressed air stream. The compressed air stream is then introduced, along with a combustor feed gas stream into a first combustor, thereby producing a first exhaust gas stream. The first exhaust gas stream is then introduced into the shell-side of an SMR, thereby providing the heat for the reforming reaction, and generating a syngas stream and a second exhaust gas stream. The second exhaust gas stream is introduced, along with a secondary fuel stream, into a second combustor, thereby producing a third exhaust gas stream. The third exhaust gas stream is then introduced into an expander, thereby producing power output and a fourth exhaust gas stream.
8
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a fastener used where an electric conductive plastic material (for example, CFRP (carbon fiber reinforced plastic)) is used as an outer skin of an aircraft, and, in particular, to a linghtning protection fastener. [0003] 2. Description of the Related Art [0004] As a fastener used when an electric conductive plastic material is used as an outer skin of an aircraft, a fastener disclosed in the Specification of U.S. Pat. No. 4,630,168 is known, in which one end surface of a head section is covered by a dielectric cap. [0005] In the fastener disclosed in the above Patent Document, the dielectric cap is positioned on the top surface of the aircraft, so that, in the case of guiding electric shock current of lightning along the top surface of the outer skin, there is a problem that the electric shock current needs to flow around this dielectric cap and the flow of electric shock current is obstructed. [0006] Moreover, from the point of view of Lightning Protection Redundancy required by section 25.981 (a) (3) of the FAR (Federal Aviation Regulation) of the United States of America, the abovementioned fastener is not appropriate because of a lack of sufficient countermeasures against deterioration of the dielectric cap due to environmental factors such as ultraviolet rays and damage due to impact from sanddust, lumps of ice and raindrops. Furthermore there is a risk of the dielectric caps peeling off (coming off) from the head section of the fastener during operation of the aircraft. BRIEF SUMMARY OF THE INVENTION [0007] In consideration of the above described problems, an object of the present invention is to provide a fastener able to prevent damage due to environmental factors such as ultraviolet rays, and impact from sanddust, without obstructing a flow of electric shock current that flows along a top surface of an outer plate. [0008] Moreover, another object of the present invention is to provide a lightning protection fastener in which any possibility of peeling off during operation of an aircraft is eliminated. [0009] In order to solve the above problems, the present invention employs the following means. [0010] The fastener according to the present invention is a fastener that connects an outer skin of an aircraft to a structural member positioned inside this outer skin, wherein there are provided a dielectric layer arranged to cover one end surface of a head section, and a conductive layer arranged to cover one end surface of this dielectric layer. [0011] According to the fastener of the present invention, since the section on the outside that is most likely to be exposed to impacts with solid bodies such as sanddust, lumps of ice, and raindrops during operation of the aircraft is covered by a conductive layer formed from a metal material (for example, copper, which is highly electrically conductive or stainless steel, which is highly corrosion protection), damage to the dielectric layer provided immediately inside the conductive layer due to ultraviolet rays, solid bodies and raindrops and so forth can be prevented. [0012] Moreover, since the dielectric layer is arranged between the conductive layer and a fastener main body, even if lightning directly strikes the conductive layer, a flow of electric shock current towards the fastener main body can be completely obstructed and the electric shock current can be safely guided to the conductive layer. [0013] It is preferable if the above conductive layer is a dielectric material having a dielectric breakdown voltage value of 100 kV/mm or greater, and it is more preferable if the above conductive layer is formed from any one of; a biaxial stretched polyethylene terephthalate (PET) film, a polyimide film, a biaxial stretched polyethylene naphthalate (PEN) film, a polyphenylene sulfide (PPS) film, or a biaxial stretched polypropylene film. [0014] According to such a fastener, since the thickness of the dielectric layer can be significantly reduced, the weight of each fastener can be significantly reduced. [0015] It is more preferable that in the fastener, the head section, the dielectric layer, and the conductive layer are connected to each other by a fixing means. [0016] According to such a fastener, since the fastener is manufactured by stitching together the head section, the dielectric layer, and the conductive layer with a string-shaped member formed from polytetrafluoroethylene or Kevlar, and then putting them in an autoclave and curing them (hot forming), peeling off of the conductive layer from the dielectric layer, and peeling off of the dielectric layer from the head section can be reliably prevented while maintaining the fastener in an excellent condition at all times. [0017] It is more preferable if in the fastener, the dielectric layer and the conductive layer are constructed as a double-layered structure, and the double-layered structure is fixed to the head section via an adhesive agent. [0018] According to such fastener, since the double-layered structure having the dielectric layer and the conductive layer is fixed to the head section via an adhesive agent (for example, epoxy adhesive agent), the fastener can be manufactured easily and quickly, and a reduction in the manufacturing cost of the fastener can be achieved. [0019] It is more preferable if in the fastener, the dielectric layer and the conductive layer are formed by means of a thermal spraying or a coating baking(curing) method. [0020] According to such a fastener, since the dielectric layer and the conductive layer are respectively formed by means of a thermal spraying or a coating baking method, the fastener can be manufactured easily and quickly, and a reduction in the manufacturing cost of the fastener can be achieved. [0021] An aircraft assembly part according to the present invention is an aircraft assembly part provided with; an outer skin-constructed with a conductive resin material as a main component, a structural member that supports this outer skin from the inside thereof, and a fastener that connects the outer skin to the structural member, and this fastener is the abovementioned fastener. [0022] According to the aircraft assembly part according to the present invention, since a flow of electric shock current towards the fastener main body is completely obstructed by the dielectric layer, a flow of the electric shock current into the conductive resin material can be completely prevented, and damage to the conductive resin material due to the electric shock current can be completely prevented. [0023] Furthermore, since an electric shock current does not flow towards the fastener main body, a DI (Dielectric Insulator) conventionally required between the structural member and a collar, and an insulating rubber cap conventionally attached to cover the whole of the top end section of the male screw section and the collar (attached to prevent a streamer that secondarily discharges electricity from the collar) can both be eliminated, and the weight of an aircraft can be significantly reduced. [0024] Moreover, the term “resin material” here includes fiber reinforced resin materials such as CFRP (carbon fiber reinforced plastics). [0025] It is more preferable in the aircraft assembly part if a conductive member is laminated on the outside surface of the conductive resin material, and the conductive layer and the conductive member are electrically connected. [0026] According to such aircraft assembly part, even if lightning were to strike the conductive layer directly, the electric shock current could be smoothly guided towards the conductive member, and also electric current that has flowed to one side (for example, the left side in FIG. 2 ) of the conductive member can be smoothly guided through the conductive layer to the other side (for example, the right side in FIG. 2 ) of the conductive member. [0027] The term “resin material” here includes fiber reinforced resin materials such as CFRP (carbon fiber reinforced plastics) [0028] According to the fastener according to the present invention, an effect in that deterioration due to environmental factors such as ultraviolet rays and damage due to impacts with sanddust, lumps of ice, and raindrops can be prevented without obstructing the flow of electric shock current along the surface of the outer skin-can be achieved. DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0029] FIG. 1A , FIG. 1B , and FIG. 1C are diagrams that show a first embodiment of a fastener of the present invention, FIG. 1A being a front view, FIG. 1B being a perspective view from above, and FIG. 1C being a perspective view from below. [0030] FIG. 2 is a vertical sectional view of an aircraft assembly part showing an outer skin and a structural member in a state of being connected by the fastener shown in FIG. 1 . [0031] FIG. 3 is a front view showing a second embodiment of the fastener of the present invention. [0032] FIG. 4 is a front view showing a third embodiment of the fastener of the present invention. [0033] FIG. 5 is a front view showing a fourth embodiment of the fastener of the present invention. [0034] FIG. 6 is an enlarged sectional view of a main part, illustrating another embodiment of the fastener of the present invention. DETAILED DESCRIPTION OF THE INVENTION [0035] Hereinafter, a first embodiment of a lightning protection fastener according to present invention is described, with reference to the drawings. [0036] As shown in FIG. 1 , the lightning protection fastener (hereinafter, referred to as the “fastener”) 1 according to the present embodiment comprises as the main components: a fastener main body 4 having a column shaped shank section (Shank) 2 and a substantially conically shaped head section (Flush Head) 3 the diameter of which becomes greater in the direction away from the shank section 2 ; a dielectric layer 5 arranged to cover one end surface (upper side end surface in FIG. 1 ( a )) of the head section 3 ; a conductive layer 6 arranged to cover one end surface (upper side end surface in FIG. 1 ( a )) of the dielectric layer 5 ; and a fixing means 7 . [0037] The fastener main body 4 is formed from the integration of the shank section 2 and the head section 3 , and is fabricated using alloy metals such as titanium (Ti-6Al-4V: annealed material) and inconel, for example. [0038] A male screw section 2 a that screws into and engages with a female screw section of a collar (nut) described later, is formed on the other end section (lower side end section in FIG. 1 ( a )) of the shank section 2 . [0039] The head section 3 is formed so that an outer diameter D 1 thereof is greater than or equal to two times an outer diameter D 2 of the shank section 2 for example, and a plurality of through holes 3 a (22 holes in the present embodiment) that pass completely through in a plate thickness direction, are provided in a circumference section of the head section 3 . [0040] The dielectric layer 5 is a disc shaped member that is formed so that the diameter thereof is equal to (or substantially equal to) the outer diameter D 1 of the head section 3 , and it is fabricated using GFRP (glass-fiber reinforced resin) for example. In the circumference section of the dielectric layer 5 , a plurality of through holes (22 holes in the present embodiment) (not shown in the diagram) passing through in the plate thickness direction, are provided at positions that correspond to the through holes 3 a provided in the circumference section of the head section 3 . With a thickness of, for example, 1.0 mm, the dielectric layer 5 is constructed to have sufficient dielectric strength, even against a lightning strike test voltage of MIL-STD-1757A Zone 1 (approximately 40 kV). In the case where GFRP is used as the dielectric layer 5 , since even a conservative estimate of the dielectric strength of GFRP is 40 kV/mm, the dielectric layer has sufficient dielectric strength even if it is subjected to a lightning strike test voltage (approximately 40 kV) of MIL-STD-1757A Zone 1 at a thickness of 1.0 mm. [0041] The conductive layer 6 is a disc shaped member formed so that the outer diameter thereof is greater than the outer diameter D 1 of the head section 3 (for example, greater by 1.0 mm), and the thickness thereof is less than that of the dielectric layer 5 (or substantially equal to the thickness of the dielectric layer 5 ). The conductive layer 6 is fabricated using metal materials having a strong spring force (that is, metal materials that do not plastically deform easily) such as CRES (Corrosion Resistant Stainless Steel) and beryllium copper. In the circumference section of the conductive layer 6 , a plurality of through holes (22 holes in the present embodiment) passing through in the plate thickness direction are provided at positions that correspond to the through holes provided in the circumference section of the dielectric layer 5 . [0042] The fixing means 7 is a string shaped member formed for example from polytetrafluoroethylene or Kevlar, and as shown in FIG. 1 , it is inserted through the through holes 3 a of the head section 3 , the through holes of the dielectric layer 5 , and the through holes 6 a of the conductive layer 6 to stitch the head section 3 , the dielectric layer 5 , and the conductive layer 6 together, and thereby secure (fasten) the head section 3 , the dielectric layer 5 , and the conductive layer 6 to each another. [0043] The fastener 1 described above is manufactured by the following steps. [0044] (1) The fastener main body 4 formed with the male screw section 2 a on the other end section of the shank section 2 , and formed with the plurality of the through holes 3 a in the circumference section of the head section 3 , the dielectric layer 5 in a state prior to curing (in a pre-impregnation state), and the conductive layer 6 formed with a plurality of through holes in the circumference section, are prepared. (2) The dielectric layer 5 is placed on one end surface of the head section 3 , and the conductive layer 6 is further placed on one end surface of this dielectric layer 5 , so that the positions of the through holes 6 a are aligned with the positions of the through holes 3 a. [0045] (3) The fixing means 7 is passed through the through holes 3 a of the head section 3 , the through holes of the dielectric layer 5 , and the through holes 6 a of the conductive layer 6 to stitch them together so that the head section 3 , the dielectric layer 5 , and the conductive layer 6 will not separate from one another. [0046] (4) The fastener 1 is placed in an autoclave for curing (hot forming). [0047] The fastener 1 manufactured as described above is used for connecting an outer skin 10 of an aircraft shown in FIG. 2 (the fixing means 7 is not shown in the diagram) to a structural member 11 (for example, a rib or a stringer), for example. Moreover, the outer skin 10 and the structural member 11 are connected by the fastener 1 to become an aircraft assembly part A (for example, a main wing assembly, a tail assembly, or a body assembly). [0048] The outer skin 10 is formed mainly from a conductive ( 1/100 to 1/1000 of the electric conductivity of aluminum) plastic material 12 (for example, CFRP (carbon fiber reinforced plastics), hereinafter referred to as “CFRP”), and an insulative resin materials 13 and 14 (for example, GFRP (glass fiber reinforced plastics), hereinafter referred to as “GFRP”) are laminated on an entire top surface (the surface positioned on the outside after assembly) and an entire back surface (the surface positioned on the inside after assembly) thereof. [0049] Furthermore, on the top surface (the surface positioned on the outside after assembly) of the GFRP 13 positioned on the top surface side of the CFRP 12 , a mesh shaped (or sheet shaped) member (for example, of copper, hereinafter referred to as “conductive mesh”) 15 , the whole of which has electric conductivity, is laminated. [0050] The structural member 11 is formed, for example, from aluminum alloy metal, titanium material, or CFRP (carbon fiber reinforced plastics), and is arranged in a predetermined position on the back surface (the surface positioned on the inside after assembly) of the GFRP 14 . [0051] Concavities (holes) 16 that pass completely through these outer skin 10 and structural member 11 in the plate thickness direction, and that can receive the fasteners 1 , are provided in predetermined positions in the structural object in which the structural member 11 is arranged on the back surface of the GFRP 14 . The fasteners 1 are accommodated in each of the concavities 16 , and collars (nuts) 17 fabricated using alloyed metals such as titanium and inconel, are fastened to the male screw sections 2 a projecting inward from the back surface of the structural member 11 . Moreover, in a state with the collar 17 fastened to the male screw section 2 a , the back surface positioned on the circumference section of the conductive layer 6 comes into contact with the top surface of the conductive mesh 15 . [0052] In FIG. 2 , the conductive layer 6 projects as much as the plate thickness thereof outward from the top surface of the conductive mesh 15 . However, the plate thickness of the conductive layer 6 is less than several 0.1 mms, and the top surface of the outer skin 10 after painting becomes substantially even since the top surfaces of the conductive layer 6 and conductive mesh 15 are eventually subjected to painting. [0053] According to the fastener 1 of the present embodiment, since the outermost place, which is highly likely to receive ultraviolet rays and the impact of sanddust, lumps of ice, raindrops, and so forth during the operation of an aircraft, is covered by the conductive layer 6 formed for example from metal materials such as copper, stainless steel, and the like, damage due to ultraviolet rays, solid bodies and the like to the dielectric layer 5 provided immediately inside the conductive layer 6 can be prevented. [0054] Moreover, since the dielectric layer 5 is arranged between the conductive layer 6 and the fastener main body 4 , even if lightning were to strike the conductive layer 6 directly, a flow of electric shock current towards the fastener main body 4 can be completely obstructed. [0055] Furthermore, since the fastener 1 is manufactured by curing (hot forming) in an autoclave after the head section 3 , the dielectric layer 5 , and the conductive layer 6 have been stitched together by the fixing means 7 , peeling off of the conductive layer 6 from the dielectric layer 5 and peeling off of the dielectric layer 5 from the head section can be reliably prevented while maintaining the fastener 1 in an excellent condition at all times. [0056] Moreover, in the case where the fastener 1 according to the present embodiment is used for connecting the outer skin 10 to a structural member 11 (for example, a rib or a stringer) of an aircraft as shown in FIG. 2 , since the back surface positioned on the circumference section of the conductive layer 6 comes into contact with the surface of the conductive mesh 15 , even if lightning were to strike the conductive layer 6 , a flow of electric shock current could be smoothly guided towards the conductive mesh 15 . Furthermore, electric shock current that has flowed from one side (for example, the left side in FIG. 2 ) of the conductive mesh 15 can be smoothly guided to the other side (for example, the right side in FIG. 2 ) of the conductive mesh 15 through the conductive layer 6 . [0057] Moreover, since the flow of electric shock current towards the fastener main body 4 is completely obstructed by the dielectric layer 5 , a flow of electric shock current into the CFRP 12 can be completely prevented, and damage to the CFRP 12 due to the electric shock current can be completely prevented. [0058] Furthermore, according to the fastener 1 of the present embodiment, since electric shock current does not flow towards the fastener main body 4 , a DI (Dielectric Insulator) conventionally required between the structural member 11 and the collar 17 for preventing sparks, and an insulating rubber cap conventionally attached to cover the whole of the top end section of the male screw section 2 a and the collar 17 (attached to prevent a streamer that secondarily discharges electricity from the collar 17 ) can both be eliminated, and the weight of an aircraft can be significantly reduced. [0059] A second embodiment according to the present invention is described, using FIG. 3 . [0060] A fastener 20 in the present embodiment differs from the above described embodiment in that a conductive layer 21 is provided instead of the conductive layer 6 described above, in which a circumference section positioned to the outside of the through holes 6 a in a radial direction is bent towards (made to face) the fastener main body 4 side (downside in FIG. 3 ). Other components are identical with those in the first embodiment described above, and descriptions for these identical components are omitted here. [0061] Moreover, the same reference symbols are given to members that are identical with those in the first embodiment. [0062] According to the fastener 20 of the present embodiment, in the case where it is used for connecting the outer skin 10 to a structural member 11 (for example, a rib or a stringer) of an aircraft as shown in FIG. 2 for example, since a back surface positioned on the circumference section of the conductive layer 21 can come into close contact with the top surface of the conductive mesh 15 , and the contact between the back surface positioned on the circumference section of the conductive layer 21 and the conductive mesh 15 can be made more reliable, even if lightning were to strike the conductive layer 6 directly, a flow of electric shock current could be more smoothly guided towards the conductive mesh 15 , and also electric shock current that has flowed from one side (for example, the left side in FIG. 2 ) of the conductive mesh 15 , can be more smoothly guided to the other side (for example, the right side in FIG. 2 ) of the conductive mesh 15 through the conductive layer 6 . [0063] Other effects are same as those in the first embodiment described above, and their descriptions are omitted here. [0064] A third embodiment according to the present invention is described, using FIG. 4 . [0065] A fastener 30 in the present embodiment differs from the first embodiment in that a double layer structure 31 in which a conductive layer 6 is laminated on the top surface of a dielectric layer 5 , is fixed on (attached to) the head section 3 of the fastener main body 4 via an adhesive agent (not shown in the diagram) . Other components are identical with those in the first embodiment described above, and descriptions for these identical components are omitted here. [0066] Moreover, the same reference symbols are given to members that are identical with those in the first embodiment. [0067] In the present embodiment, GFRP having a thickness of 1.0 mm is used as the dielectric layer 5 , and copper foil having a thickness of 0.2 mm (a thickness of 30 μm may even be used) is used as the conductive layer 6 . [0068] Moreover, epoxy adhesive agent (for example, the epoxy adhesive agent EA9396 made by the company Hysol-Dexter) is used as the adhesive agent. [0069] The fastener 30 described above is manufactured in following steps. [0070] (1) After the conductive layer 6 has been laminated on (placed on) the surface (top) of the dielectric layer 5 prior to curing (in a pre-impregnation state) and these have been impregnated with epoxy resin, these layers are subjected to heat curing to manufacture the double layer structure 31 . [0071] (2) The fastener main body 4 formed with the male screw section 2 a on the other end of the shank section 2 is prepared, particles (for example, hard particles such as metal, ceramic or glass of average particle diameter 200 μm or less(more preferably, average particle diameter between 10 μm and 100 μm)) are shot blasted on one end surface (top surface) of the head section 3 to carry out a pre-processing for roughening the top surface of the head section 3 . [0072] Sand paper and so forth may also be used instead of shot blasting to roughen the top surface of the head section 3 . [0073] (3) Water break free processing (a method for applying sanding until the surface stops repelling) by sanding is carried out on the exposed surface of the dielectric layer 5 of the two layer structure 31 . [0074] (4) After adhesive agent is applied on the one end surface of the head section 3 , the two layer structure 31 is placed thereon, and by hardening the adhesive agent, the two layer structure is fixed onto the head section 3 . [0075] According to the fastener 30 of the present embodiment, since the outermost place, which is highly likely to receive ultraviolet rays and the impact of sanddust, lumps of ice, raindrops, and so forth during the operation of an aircraft, is covered by the conductive layer 6 formed for example from a metal material such as copper, stainless steel, and the like, damage due to ultraviolet rays, solid bodies and the like to the dielectric layer 5 provided immediately inside the conductive layer 6 can be prevented. [0076] Moreover, since the dielectric layer 5 is arranged between the conductive layer 6 and the fastener main body 4 , even if lightning were to strike the conductive layer 6 directly, a flow of electric shock current towards the fastener main body 4 can be completely obstructed. [0077] Furthermore, since the double layer structure 31 provided with the dielectric layer 5 and the conductive layer 6 is fixed onto the head section 3 via an adhesive agent, easier and quicker production of the fastener 30 can be achieved, and a greater reduction in production cost can be achieved compared to the fastener of the first embodiment described above. [0078] Moreover, since pre-processing for surface-roughening has been applied to the top surface of the head section 3 , the double layer structure 31 can be reliably fixed (firmly) onto the head section 3 , and peeling off of the double layer structure 31 from the head section 3 can be reliably prevented during aircraft operation, while maintaining the fastener 30 in an excellent condition at all times. [0079] Furthermore, in the case where the fastener 30 according to the present embodiment is used for connecting the outer skin 10 to a structural member 11 (for example, a rib or a stringer) of an aircraft as shown in FIG. 2 , since the back surface positioned on the circumference section of the conductive layer 6 comes into contact with the surface of the conductive mesh 15 , even if lightning were to strike the conductive layer 6 , a flow of electric shock current could be smoothly guided towards the conductive mesh 15 , and furthermore, electric shock current that has flowed from one side (for example, the left side in FIG. 2 ) of the conductive mesh 15 can be smoothly guided to the other side (for example, the right side in FIG. 2 ) of the conductive mesh 15 through the conductive layer 6 . [0080] Moreover, since the flow of electric shock current towards the fastener main body 4 is completely obstructed by the dielectric layer 5 , a flow of electric shock current into the CFRP 12 can be completely prevented, and damage to the CFRP 12 due to the electric shock current can be completely prevented. [0081] Furthermore, according to the fastener 30 of the present embodiment, since electric shock current does not flow towards the fastener main body 4 , a DI (Dielectric Insulator) conventionally required between the structural member 11 and the collar 17 for preventing sparks, and an insulating rubber cap conventionally attached to cover the whole of the top end section of the male screw section 2 a and the collar 17 (attached to prevent a streamer that secondarily discharges electricity from the collar 17 ) can both be eliminated, and the weight of an aircraft can be significantly reduced. [0082] A fourth embodiment according to the present invention is described, using to FIG. 5 . [0083] A fastener 40 in the present embodiment differs from the above described third embodiment in that a conductive layer 21 is provided instead of the conductive layer 6 described above, in which a circumference section positioned to the outside of the through holes 6 a in a radial direction is bent towards (made to face) the fastener main body 4 side (downside in FIG. 5 ). Other components are identical with those in the third embodiment described above, and descriptions for these identical components are omitted here. [0084] Moreover, the same reference symbols are given to members that are identical with those in the third embodiment. [0085] According to the fastener 40 of the present embodiment, in the case where it is used for connecting the outer skin 10 to a structural member 11 (for example, a rib or a stringer) of an aircraft as shown in FIG. 2 for example, since a back surface positioned on the circumference section of the conductive layer 21 can come into close contact with the top surface of the conductive mesh 15 and the contact between the back surface positioned on the circumference section of the conductive layer 21 and the conductive mesh 15 can be made more reliable, even if lightning were to strike the conductive layer 6 directly, a flow of electric shock current could be more smoothly guided towards the conductive mesh 15 , and also electric shock current that has flowed from one side (for example, the left side in FIG. 2 ) of the conductive mesh 15 can be more smoothly guided to the other side (for example, the right side in FIG. 2 ) of the conductive mesh 15 through the conductive layer 6 . [0086] Other effects are same as those in the third embodiment described above, and their descriptions are omitted here. [0087] Moreover, the present invention is not limited to the embodiments described above, and instead of the double layer structure 31 , a double layer structure that uses PET (for example, Luminar manufactured by Toray Industries, Inc.) of thickness 120 μm as the dielectric layer 5 , and copper foil of thickness 30 μm as the conductive layer 6 may be used. [0088] By using PET as the dielectric layer 5 as described, the thickness of the dielectric layer 5 can be significantly reduced, and the weight of each fastener can be significantly reduced. [0089] A dielectric breakdown voltage of GFRP is approximately 40 kV/mm, whereas a dielectric breakdown voltage of PET (biaxial stretched polyethylene terephthalate) is approximately 300 kV/mm. [0090] Furthermore, in the case of using Luminar manufactured by Toray Industries, Inc. as the dielectric layer 5 , the thickness thereof is preferably any one of 100 μm, 125 μm, 188 μm, 210 μm, or 250 μm. [0091] Moreover, instead of the double layer structure 31 , a double layer structure that uses polyimide (kapton) of thickness 125 μm as the dielectric layer 5 , and copper foil of thickness 30 μm as the conductive layer 6 may be used. [0092] By using polyimide as the dielectric layer 5 as described, the thickness of the dielectric layer 5 can be significantly reduced, and the weight of each fastener can be significantly reduced. [0093] A dielectric breakdown voltage of GFRP is approximately 40 kV/mm, whereas a dielectric breakdown voltage of polyimide is approximately 300 kV/mm. [0094] Moreover, in the case where polyimide is used as the dielectric layer 5 in this way, the double layer structure may be fixed on the head section by means of heat bonding using the polyimide layer instead of using the epoxy adhesive agent (for example, epoxy adhesive agent EA9396 manufactured by the company Hysol-Dexter) described above. [0095] Furthermore, instead of the double layer structure 31 , a double layer structure that uses biaxial stretched polyethylene naphthalate (PEN) (for example, Teonex manufactured by Tejin, Inc.) of thickness 125 μm as the dielectric layer 5 , and copper foil of thickness 30 μm as the conductive layer 6 may be used. [0096] By using PEN as the dielectric layer 5 as described, the thickness of the dielectric layer 5 can be significantly reduced, and the weight of each fastener can be significantly reduced. [0097] A dielectric breakdown voltage of GFRP is approximately 40 kV/mm, whereas a dielectric breakdown voltage of PEN (biaxial stretched polyethylene terephthalate film) is 300 kV/mm to 400 kV/mm. [0098] Moreover, in the case where Teonex manufactured by Teijin, Inc. is used as the dielectric layer 5 , the thickness thereof is preferably any one of 75 μm, 100 μm, 188 μm, or 250 μm. [0099] Furthermore, the dielectric layer 5 and the conductive layer 6 may be formed on the top surface of the head section 3 by means of thermal spraying (for example, plasma spraying, electric arc spraying, HVOF spraying or the like) instead of adhering (hot bonding ) the double layer structure onto the top surface of the head section 3 . [0100] Specifically, an alumina dielectric layer is sprayed on the top surface of the head section 3 and a copper conductive layer is sprayed thereon. [0101] The dielectric layer 5 is not limited to alumina. Moreover a sealing process may be carried out by means of impregnation with a silicone or polyimide solution to improve its dielectric property, since the dielectric property of thermal spraying coating is degraded by the presence of voids in the coating. [0102] Furthermore, the dielectric layer 5 and the conductive layer 6 may be formed on the top surface of the head section 3 by means of a coating baking method instead of adhering (hot bonding) the double layer structure on the top surface of the head section 3 . [0103] Specifically, polyimide is coated on the head section 3 by carrying out coating, drying and baking , using polyimide varnish (solution), for example, Polyimide Varnish (U-Varnish) manufactured by Ube Industries, Inc. In order to increase the thickness of the polyimide layer, the steps of coating, drying, and baking may be carried out repeatedly. [0104] Subsequently, silver paste is coated on the top surface of the polyimide layer to form the conductive layer. [0105] Furthermore, it is even more preferable if the outer diameter of the dielectric layer 5 is equal to (or substantially equal to) the outer diameter of the conductive layer 6 as shown in FIG. 6 , that is, if the outer diameter of the dielectric layer 5 is greater than the outer diameter D 1 of the head section 3 (for example, greater by 1.0 mm). [0106] Accordingly, since the flow of electric shock current towards the fastener main body 4 is completely obstructed by the dielectric layer 5 , a flow of electric shock current into the CFRP 12 can be completely prevented, and damage to the CFRP 12 due to the electric shock current can be completely prevented. [0107] Furthermore, it is more preferable if a second dielectric layer 5 a is provided around the circumferential direction on the circumference section positioned on the outside in the radial direction of the head section 3 as shown in FIG. 6 . [0108] Accordingly, inflow of electric current due to secondary discharge of lightening can be prevented. [0109] Furthermore, the shank section 2 may be wet-installed, using an electrically conductive compound. As a result, the contact between the shank section 2 and the CFRP 12 can be made more reliable, and an electric potential of the fastener when electric shock current is loaded (when struck by lightening) can be fixed lower.
There is provided a fastener able to prevent damage due to environmental factors such as ultraviolet rays, and impact from sanddust, lumps of ice, and raindrops without obstructing a flow of electric shock current that flows along a top surface of an outer skin. The fastener connects an outer skin of an aircraft to a structural member positioned inside this outer skin, and is provided with a dielectric layer arranged to cover one end surface of a head section, and a conductive layer arranged to cover one end surface of this dielectric layer.
5
FIELD OF THE INVENTION A new family of viscosification agents based on terpolymers of N-vinyl-2-pyrrolidone-sodium styrene sulfonate-methacrylamidopropyltrimethylammonium chloride is described as an improved viscosity control additive for water-based drilling muds. The present invention relates to these terpolymer materials which function as viscosification agents when added to water-based muds which are fluids used to maintain pressure, cool drill bits and lift cuttings from the holes in the drilling operation for oil and gas wells. the terpolymers have about 40 to 98 mole % N-vinyl-2-pyrrolidone units, about 1 to about 50 mole % sodium styrene sulfonate units and about 1 to about 50 mole % methacrylamidopropyltrimethylammonium chloride units. Normally, the latter two units comprise less than 60 mole% of the total polymer composition. A soluble, low molecular weight acid, base or salt can be added to the aqueous mud solution, wherein the rheological properties of the drilling fluid is markedly enhanced. The drilling muds formed from these polymeric materials exhibit improved low and high temperature rheological properties as compared to drilling muds formed from homogeneous-charged polymers, i.e., polyelectrolytes. The improved high temperature performance of these polymers, especially in acidic environments, is due to the hydrolytic stability of the N-vinyl-2-pyrrolidone units. BACKGROUND OF THE INVENTION In the field of drilling in the exploration for oil and gas, an important component is that of the formulation of drilling muds. Drilling muds are the fluids which are used to maintain pressure, cool drill bits and lift cuttings from the holes, and vary in composition over a wide spectrum. Generally, drilling muds are based on aqueous formulations or oil-based formulations. A conventional water-based drilling mud formulation is comprised of basically the following ingredients: water, a clay such as bentonite, lignosulfonate, a weighting agent such as BaSO 4 (Barite), and a caustic material such as sodium hydroxide and a caustic material such as caustic barite, to adjust the pH of the drilling mud to a pH of about 10 to about 10.5. In addition to cooling the drill bit and sweeping out the drilling fines from the vicinity of bit, the muds are capable of imparting a substantial positive pressure on a formation through its high density. This latter feature is due to the addition of high concentrations of insoluble, solid, high density particulates (i.e., weighting agents) such as barite. However, these particulates inhibit the drilling rate and possibly damage a variety of underground formations. This problem becomes even more acute as the drilling fines are "introduced" into the mud. Therefore, there has been a substantial need for a homogeneous, high density drilling mud which exhibits good performance at both high temperature and high ionic strength. As alluded to previously, a very desirable change in the formulation of a drilling fluid would be the elimination of all added particulates. One practical approach to this problem is to formulate a drilling fluid that is clear, homogeneous, dense, single phase and possesses the appropriate viscosity requirements (in general, 40 to 50 cps). Therefore, a water-based mud containing principally a polymeric viscosifier in a high concentration brine (weighting agent) could meet the above-stated requirements. Such a fluid would be quite economical since some processing steps (and materials) are eliminated. For instance, brine can be obtained directly at the drill site. However, it should be pointed out that the ability of macromolecules to effectively viscosify a high ionic strength solution is generally poor, since the dimensions of the polymer chains tend to collapse under these conditions. This is especially true for polyelectrolytes (i.e., homogeneous-charged polymers). A collapse in the dimensions of the chain results in significant loss in viscosity. Therefore, it is imperative for successful use of polymers in high ionic strength solutions that chain expansion rather than contraction should take place. Polymeric materials composed of N-vinyl-2-pyrrolidone (NV2P), sodium styrene sulfonate (SSS) and methacrylamidopropyltrimethylammonium chloride (MAPTAC) were observed to enhance the viscosity of aqueous solutions containing high levels of salt, acid or, base. these materials meet the requirements for producing a homogeneous, single phase, high density, water-based drilling mud. The N-vinyl-2-pyrrolidone units impart a substantially improved high temperature stability to the drilling fluid due to their own intrinsic hydrolytic stability. There has been substantial need for a water-based drilling fluid which would exhibit good performance at high temperature. Previous experience has shown that most polymeric viscosifiers are effective in salt-free (i.e., fresh water) systems; however, they lose their effectiveness upon the addition of salt. As the temperature is increased, the viscosity loss becomes even more pronounced. There is need, therefore, for a polymeric viscosifier which can maintain viscosity and gel strength in high ionic strength, weighing agent-free (or at low concentrations), water-based muds up to high temperatures (exceeding 300° F.). These needs are not adequately met by the current viscosifiers. This invention describes an approach to viscosification of water-based drilling muds which permits the substitution of N-vinyl-2-pyrrolidone-based polyampholyte terpolymers for amine clays and barite (weighting agent). The resulting polymer-modified drilling fluid displays rheological properties which are in a desirable range for drilling mud applications, based on tests conducted for 16 hours at a variety of temperatures. The types of N-vinyl-2-pyrrolidone-based polyampholytes that are envisioned in the present invention include N-vinyl-2-pyrrolidone as the nonionic monomer unit and the following anionic and cationic species: Anionic: 2-acrylamido-2-methylpropane sulfonic acid, sodium styrene sulfonate, (meth)acrylic acid, 2-sulfoethylmethacrylate and the like. Cationic: Methacrylamidopropyltrimethylammonium chloride, dimethyldiallylammonium chloride, diethyldiallylammonium chloride, 2-methacryloxy-2ethyltrimethylammonium chloride, trimethylmethacryloxyethylammonium methosulfate, 2-acrylamido-2-methylpropyltrimethylammonium chloride, vinylbenzyltrimethylammonium chloride and the like. These monomers possess the appropriate water solubility so that polymerization can take place. The preferred species of the instant invention is low to moderate charge density N-vinyl-2-pyrrolidonebased polyampholytes with approximately 1 to about 60 mole % ionic groups. A 1:1 molar ratio of anionic and cationic is not required for effective utilization of this polymer. It is found that these terpolymers are soluble (low charge density) or readily dispersible (moderate charge density) in fresh water systems. Homogeneous, clear solutions form with the addition of soluble acid, base, or salt showing that the polymer is readily soluble in these solutions. In addition, the viscosity increases with the addition of these solutes. As a consequence, these polymers are extremely effective viscosifiers in a high ionic strength, water-based mud, even at relatively low levels. Moreover, the hydrolytic stability of the N-vinyl-2-pyrrolidone moieties imparts a substantially improved high temperature stability to the water-based drilling fluid. SUMMARY OF THE INVENTION A new family of viscosification agents based on terpolymers of N-vinyl-2-pyrrolidone-sodium styrene sulfonate-methacrylamidopropyltrimethylammonium chloride is described as an improved viscosity control additive for water-based drilling muds. The present invention relates to these terpolymer materials which function as viscosification agents when added to water-based muds which are fluids used to maintain pressure, cool drill bits and lift cuttings from the holes in the drilling operation for oil and gas wells. The terpolymers have about 40 to 98 mole % N-vinyl-2-pyrrolidone units, about 1 to about 50 mole % sodium styrene sulfonate units and about 1 to about 50 mole % methacrylamidopropyltrimethylammonium chloride units. Normally, the latter two units comprise less than 60 mole % of the total polymer composition. A soluble, low molecular weight acid, base or salt can be added to the aqueous mud solution, wherein the rheological properties of the drilling fluid is markedly enhanced. GENERAL DESCRIPTION The present invention describes a new class of viscosification agents for water-based drilling muds which are used during operation of gas and oil wells, wherein these viscosification agents are intermolecular complexes, i.e., polyampholytes containing primarily N-vinyl-2-pyrrolidone with low to moderate concentrations of anionic and cationic groups. These latter two units are not necessarily present in a 1:1 molar ratio. Typically, the cationic monomer unit is methacrylamidopropyltrimethylammonium chloride (MAPTAC) and the anionic monomer unit is sodium styrene sulfonate (SSS). However, many water soluble anionic and cationic monomer units can be substituted for MAPTAC and SSS units. It is the placement of these oppositely-charged species onto the polymer chain that imparts substantially different physical properties to these materials, as compared to homogeneous-charged macromolecules, i.e., polyelectrolytes. The water-based drilling muds of the instant invention minimally comprise, but can also include other additives, if necessary, an aqueous liquid such as fresh water or salt water; a clay such as bentonite; lignosulfonate as a viscosifier; a weighting material such as barite (BaSO 4 ), and a caustic material such as a sodium hydroxide or lime added to adjust pH to about 10.0 to 10.5. In general, the specific gravity is about 7 pounds per gallon to about 20 pounds per gallon, more preferably about 10 to 18, and most preferably about 12 to about 16. A typical, but non-limiting example of a caustic material which can be readily employed is sodium hydroxide or lime. A typical, but non-limiting example of a suitable clay additive is bentonite. A typical, but non-limiting examples of a weighting agent which can be readily employed is barite or a barium sulfate, which may optionally be surface treated with a variety of other cations, such as calcium. The terpolymers are formed by a free radical copolymerization process. The principal monomer used in the free radical aqueous solution copolymerization process is N-vinyl-2-pyrrolidone monomer, which is copolymerized with an anionic monomer (typically, sodium styrene sulfonate) and a cationic monomer (typically, methacrylamidopropyltrimethylammonium chloride). A typical water-based drilling mud, as envisioned by the instant invention, comprises water or salt water; weighting material necessary to give the desired mud density; about 0.25 to about 5 lb/bbl. of the N-vinyl-2-pyrrolidone/sodium styrene sulfonate/methacrylamidopropyltrimethylammonium chloride intrapolymer complex; and sufficient concentration of base to adjust the pH of the water-based drilling mud to about 10.0 to about 10.5. Higher levels of the sulfonated polymer can be employed but it is not normally economically attractive. The drilling mud may also contain a clay such as Bentonite, at a concentration level of about 4 to about 30 lb/bbl., wherein the clay is added to the drilling mud to promote circulation and improve hole stability and cleaning. A lignosulfonate, which is a deflocculation agent, can be added to the drilling mud at a concentration level of about 1 to about 30 lb/bbl. Alternatively, a typical water-based drilling mud, as envisioned by the instant invention, comprises water in which sufficient salt (such as iron-chloride, iron bromide and calcium bromide) is dissolved to give the desired mud density, and about 0.25 to about 5 lb/bbl. of the N-vinyl-2-pyrrolidone-MAPTAC-SSSterpolymer. Higher levels of the terpolymer can be employed, but, it is not economically attractive. The mud may contain a sufficient concentration of base to adjust the pH of the water-based mud to its appropriate level (normally 10.0 to 10.5). The attractive feature of this mud is the elimination of high concentrations of insoluble, solid, high density particulates (example, weighting agents). In some instances, these particulates inhibit the drilling process through damage of the underground formation and reduction in the drilling rate. The terpolymers of the instant invention are formed by a free radical terpolymerization process in an aqueous medium of an N-vinyl-2-pyrrolidone monomer, a sodium styrene sulfonate monomer and a methacrylamidopropyltrimethylammonium chloride monomer. The resultant water soluble terpolymer has the formula: ##STR1## wherein x is about 40 to aout 98 mole %, more preferably about 50 to about 95, and most preferably about 80 to about 90, y is about 1 to about 50 mole %, more preferably about 2 to about 20 and most preferably about 5 to about 10, and z is about 1 to about 50 mole %, more preferably about 2 to about 20, and most preferably about 5 to about 10, wherein y is z are less than 60 mole %, and M is an amine, or a metal cation selected from the group consisting of aluminum, iron, lead, Groups IA, IIA, IB and IIB of the Periodic Table of Elements. The molecular weight as derived from intrinsic viscosities, for the terpolymers of N-vinyl-2-pyrrolidone/sodium styrene sulfonate/methacrylamidopropyltrimethylammonium chloride is about 10 3 to about 5×10 6 , more preferably about 10 4 to about 2×10 6 and most preferably about 10 5 to about 10 6 . The means for determining the molecular weights of the water soluble terpolymers from the viscosity of solutions of the terpolymers comprises the initial isolation of the water soluble terpolymers, purification and redissolving the terpolymers in water to give solutions with known concentrations. The flow times of the solutions and the pure solvent were measured in a standard Ubbelholde viscometer. Subsequently, the reduced viscosity is calculated through standard methods utilizing these values. Extrapolation to zero polymer concentration leads to the intrinsic viscosity of the polymer solution. The intrinisic viscosity is directly related to the molecular weight through the well-known Mark Houwink relationship. The water soluble terpolymers of N-vinyl-2-pyrrolidone/sodium styrene sulfonate/methacrylamidopropyltrimethylammonium chloride are formed by a conventional free radical terpolymerization in an aqueous medium which comprises the steps of forming a reaction solution of N-vinyl-2-pyrrolidone monomer, sodium styrene sulfonate monomer and methacrylamidopropyltrimethylammonium chloride monomer (50 wt. % solution in water) in distilled water, wherein the total monomer concentration is about 1 to about 40 grams of total monomer per 100 grams of water, more preferably about 5 to about 30, and most preferably about 10 to about 20; purging the reaction solution with nitrogen; adding base to the reaction solution to adjust the pH of the reaction solution to about 8.0 to 9.0; etc. sufficient acid to the reaction solution to adjust the pH of the reaction solution to about 4.5 to 5; heating the reaction solution to at least 55° C. while maintaining the nitrogen purge, adding sufficient free radical initiator to the reaction solution at 55° C. to initiate terpolymerization of the N-vinyl-2-pyrrolidone monomer, the sodium styrene sulfonate monomer, and the methacrylamidopropyltrimethylammonium chloride monomer; terpolymerizing said monomers of N-vinyl-2-pyrrolidone, sodium styrene sulfonate and methacrylamidopropyltrimethylammonium chloride at a sufficient temperature and for a sufficient period of time to form said water soluble terpolymer; and recovering said water soluble terpolymer from said reaction solution. In general, the N-vinyl-2-pyrrolidone, anionic and cationic monomers are dissolved in a water phase in the presence of an initiator, wherein the temperature is sufficient to initiate polymerization. The resultant terpolymer is added to the drilling mud formulation at about 0.5 to about 20 lb/bbl. The total concentration of monomers in the water is about 1 to about 40 grams of total monomer per 100 grams of water, more preferably about 5 to about 30, and most preferably about 10 to about 20. Terpolymerization of the N-vinyl-2-pyrrolidone monomer, sodium styrene sulfonate monomer, and methacrylamidopropyltrimethylammonium chloride monomer is effected at a temperature of about 30 to about 90, more preferably at about 40 to about 70, and most preferably at about 50 to about 60 for a period of time of about 1 to about 24 hours, more preferably about 3 to about 10, and most preferably about 4 to about 8. A suitable method of recovery of the formed water soluble terpolymer from the aqueous reaction solution comprises precipitation in acetone, methanol, ethanol and the like. Suitable free radical initiators for the free radical terpolymerization of the N-vinyl-2-pyrrolidone monomers, the sodium styrene sulfonate monomer, and the methacrylamidopropyltrimethylammonium chloride monomer are selected from the group consisting of potassium persulfate, benzoyl peroxide, hydrogen peroxide, azobisisobutyronitrile and the like. The concentration of the free radical initiator is about 0.001 to about 2.0 grams of free radical initiator per 100 grams of total monomer, more preferably about 0.01 to about 1.0, and most preferably about 0.05 to about 0.1. It should be pointed out that neither the mode of polymerization (solution, suspension, or emulsion polymerization technique and the like) nor the initiator is critical, provided that the method or the product of the initiation step does not inhibit production of the polyampholyte or chemically modify the initial molecular structure of the reacting monomers. DESCRIPTION OF THE PREFERRED EMBODIMENTS The following examples illustrate the present invention, without; however, limiting the same hereto. EXAMPLE 1 A representative example for the synthesis of these terpolymers is outlined below. Into a 1-liter, 4-neck flask add: 6.64 g MAPTAC (50% solution) 30 g N-vinyl-2-pyrrolidone 3.1 g sodium styrene sulfonate 300 ml. distilled water 1.0 ml. ammonium hydroxide We should emphasize at this time that the anionic and cationic monomers were added to the aqueous phase without attempting to form ion-pair comonomers that do not possess nonpolymerizable counterions. The solution was purged with nitrogen gas for one hour to remove dissolved oxygen. As the nitrogen gas purging began, the solution was heated to 55° C. At this point, 0.05 g azobisisobutyronitrile was added to the solution. After 24 hours, the polymer was precipitated from solution with acetone. Subsequently, the resulting polymer was washed several times with a large excess of acetone and dried in a vacuum oven at 60° C. for 24 hours. EXAMPLE 2 Presented in Table I are representative data on the rheological properties of NV2P-SSS-MAPTAC terpolymer composed of approximately 90 mole % NV2P, 5 mole % MAPTAC and 5 mole % SSS dissolved in a variety of salt and acid environments. In all instances, the properties were measured initially at room temperature. Subsequently, the solutions were heated in a bomb at 150° F. for four hours, cooled to room temperature and the properties measured again. This procedure is repeated again at 400° F. The results show that this polyampholyte is very effective at enhancing the rheological properties of high ionic strength aqueous fluids at room temperature, 150° F. and with relatively modest change upon the 400° F. heat treatment. Undoubtedly, this N-vinyl-2-pyrrolidone based polyampholyte is both chemically and thermally stable in these solution environments. Furthermore, marked improvement in the rheological properties of these water-based mud systems is obtained through moderate increases in either (or both) charge density and molecular weight of the polyampholyte. In any case, these properties (see Table I) compared favorably with conventional (and commercially available) oil-based muds where amine-treated clays are used as the viscosification agent. TABLE I______________________________________PERFORMANCE OF NV2P POLYAMPHOLYTESIN HIGH IONIC STRENGTH AQUEOUSSOLUTIONS (HOMOGENEOUS SYSTEMS)Concentration AmineWeight NV2P NV2P ClayPercent 2.0.sup.(a) 2.0.sup.(b) NV2P.sup.(c) 1.0______________________________________ 70° F. 600 66 18 14 -- YP 4 2 2 -- 10 Gel 5 4 4 --150° F. 600 64 18 13 50 YP 4 2 1 10 10 Gel 4 3 4 9400° F. 600 52 30 -- 44 YP 4 4 -- 0 10 Gel 4 3 -- 3______________________________________ .sup.(a) 11.3 lb/gal CaCl brine. .sup.(b) 10.0 lb/gal NaCl brine. .sup.(c) 15% HCl solution. EXAMPLE 3 A representative example for the synthesis of a NV2P-MAPTAC-(2-acrylamido-2-methylpropanesylfonic acid) AMPS terpolymer is outlined below. Into a 1-liter, 4 neck flask add: 3.1 g AMPS (acid form) 0.6 g sodium hydroxide 30 g n-vinyl-2-pyrrolidone 6.6 g MAPTAC (50% solution) 150 ml distilled water The NV2P was vacuum distilled at 56° C./0.6 mm Hg and MAPTAC was purified through addition of activated charcoal (3% by weight) to the as-received monomer solution. The charcoal was filtered from solution via conventional separation methods prior to addition to the reaction flask. Again we emphasize that the anionic and cationic monomers were added to the aqueous phase without attempting to form ion-pair comonomers that do not possess nonpolymerizable counterions. The solution was purged with nitrogen gas for one hour to remove dissolved oxygen. As the nitrogen gas purging began, the solution was heated to 50° C. At this point, 0.1 g azobisisobutyronitrile (AIBN) was added to the solution. AIBN was dissolved directly into a small quantity of NV2P prior to addition to the reactant mixture. After 24 hours, the terpolymer was precipitated from solution with acetone. Subsequently, the resulting polymer was washed several times with a large excess of acetone and dried in a vacuum oven at 60° C. for 24 hours. This particular terpolymer is used in the subsequent examples. EXAMPLE 4 A variety of aqueous solutions containing a NV2P-MAPTAC-AMPS terpolymer (example 3) were formed at 1 g/dl polymer concentration. These solutions were heated for four (4) hours at a particular temperature, cooled to room temperature and the viscosity was measured in a standard Brookfield viscometer. This procedure was continued up to 90° C. The results are presented in Table II. TABLE II______________________________________Performance of a NV2P-MAPTAC-AMPS terpolymerPolyampholyte in High Ionic Strength AqueousSolutions as a Function of Temperature Viscosity, CPSTemperature Distilled 30% 2 Molar 3.4 Molar(°C.) Water HCL CaCl.sub.2 NaCl______________________________________25 8.8 16.0 18.8 1540 11.3 17.5 23.8 16.270 8.8 16.0 22.6 16.090 12.5 17.0 24.6 18.8______________________________________ The results show that this polyampholyte terpolymer is very effective at enhancing the rheological properties of high ionic strength aqueous fluids at room temperature and elevated temperatures. The viscosity of these solutions remains essentially invarient to temperature changes. Undoubtedly, this terpolymer is both chemically and thermally stable in high ionic strength environments. Furthermore, these polymeric materials are especially useful as a high temperature viscosifier for water-based drilling fluids where the weighing agent is the dissolved salt or acid.
A new family of terpolymers based on V-vinyl-2-pyrrolidone/sodium styrene sulfonate/methacrylamidopropyltrimethylammonium chloride has been found to be an improved viscosity control additive for water-based drilling muds. The resultant muds display good viscosity characteristics, thermal stability and gel strength when formulated from the terpolymer intramolecular complex having the appropriate polymer concentration and salt level.
2
The present invention relates turbines, and more particularly to a method of introducing air into a gas turbine combustor to reduce combustor NOx emissions and water requirements in reducing such emissions. BACKGROUND OF THE INVENTION Gas turbine engines include a compressor for compressing air that is mixed with fuel and ignited in a combustor for generating combustion gases. The combustion gases from the combustor flow to a turbine that extracts energy for driving a shaft to power the compressor and produces output power, often for powering an electrical generator. Increased requirements for low emissions from turbine power plants now require low rates of emissions of NOx (mono-nitrogen oxides NO (nitric oxide) and NO 2 (nitrogen dioxide)), CO (carbon monoxide) and other pollutants from turbine combustors. Conventional turbine combustors use non-premixed diffusion flames, where fuel and air freely enter the combustion chamber separately and mixing of the fuel and air occurs simultaneously with combustion, and where resulting flame temperatures typically exceed 4000° F. with NG, LF or syngas fuels, so as to produce relatively high levels of NOx emissions. Thus, temperatures in combustion chamber primary zones can get very high if water is not injected, although temperatures do drop along the length of the combustion chamber. Water is generally used because a diffusion flame is used in these combustors and primary zone temperatures are very high and produce NOx as much as approximately 250 ppm with syngas/LF fuels and approximately 120 ppm with NG fuel if water is not used. Approximately 95% of the combustor exiting NOx, which is measured in ppmvd (parts per million, volumetric dry) @15% O2, has already been formed before the combustion gases reach the dilution holes in a conventional combustor liner. NOx formation rates are highest in a narrow zone of the combustion chamber, and become very much less so after the combustion gases reach the dilution holes in the conventional combustor liner. Thus, air introduced by dilution holes in a conventional combustor liner does not participate in a reduction of combustion gases' temperatures and NOx production. As is explained in the background section of U.S. Pat. No. 6,192,689, one method commonly used to reduce peak temperatures in conventional diffusion flame combustors, and thereby reduce NOx emissions, is to inject water or steam into the combustor. However, water or steam injection is a relatively expensive technique and can cause the undesirable side effect of quenching (i.e., rapid cooling) carbon monoxide (CO) burnout reactions, and which is limited in its ability to achieve low levels of pollutants. Conventional diffusion flame combustors are effective for burning natural gas (NG), synthesis gas (syngas) and liquid fuels (LF) in low megawatt (MW) turbine machines. But conventional combustors use a very old liner cooling design that involves the use of water or steam injection, which is not desirable in gas turbine power plants from life of components, operability and cost of electricity perspectives. Sufficient efforts have not been made to reduce water consumption in these machines. BRIEF DESCRIPTION OF THE INVENTION The present invention seeks to reduce water requirements in conventional combustors to reduce temperatures and NOx emissions when operating on NG/LF or syngas fuels. In the present invention, combustion in a conventional combustor is changed from “rich to lean” to “rich to quench to lean” by changing the air entry arrangement in the liner of the conventional combustor. In this changed air entry arrangement, dilution holes are removed, liner cooling is reduced and dilution air is admitted into the combustor liner in place of mixing air admitted into the combustor liner through a third row of mixing holes. In an alternative embodiment, dilution air is admitted into the combustor liner with the help of a plurality of pipes arranged in such a manner so that such air comes into the liner as a swirling flow in a direction opposite to nozzle swirl, so as to thereby produce a large mixing of air with the combustion gases and a resulting quenching effect, i.e., a rapid cooling of the combustion gases by quenching air. As such, the requirement for cooling water to quench the combustion gases is significantly reduced, thereby helping in turbine efficiency and a reduction in turbine emissions. The present invention reduces temperatures in the primary reaction zone of a combustor by moving dilution air upstream and providing swirl to incoming air to enhance mixing. Reduction in temperature leads to reduction in NOx generation which is very high in conventional liners before combustion gases reach the dilution holes in the combustor. The present invention also reduces the cooling water requirement in conventional liners, which is typically very high. In a first embodiment of the present invention, a combustor operating with a compressor to drive a gas turbine is comprised of an outer combustor wall having an upstream fuel entry end and a downstream turbine entry end; a plurality of mixing holes located proximal to the upstream fuel entry end of the outer combustor wall; and a plurality of dilution holes located proximal to the plurality of mixing holes to admit air into a combustion zone in the combustor for mixing of the admitted air with combustion gases in the combustion zone to thereby reduce NOx and carbon monoxide (CO) production in the combustion zone. In another embodiment of the present invention, a combustor operating with a compressor to drive a gas turbine is comprised of an outer combustor wall having an upstream fuel entry end and a downstream turbine entry end; a plurality of mixing holes located proximal to the upstream fuel entry end of the outer combustor wall, the plurality of mixing holes being arranged in a plurality of rows which extend around a circumference of the outer combustor wall; and a plurality of dilution holes arranged in one or more rows which extend around the circumference of the outer combustor wall, the plurality of dilution holes being located proximal to the plurality of mixing holes; an outer shell; a nozzle from which compressed air and fuel are discharged into combustor; a flow sleeve located between the outer shell and the combustor wall so as to form a cavity between the outer shell and the combustor wall so that air from the compressor entering the combustor is divided between a first path by which a first part of the compressor air is admitted into the combustor by entering through the flow sleeve, and a second path by which a second part of the compressor air is admitted into the combustor through the cavity; and a plurality of pipes extending between the cavity and the plurality of dilution holes to admit the second part of the compressor air into the combustion zone for increased mixing of the admitted air with combustion gases in the combustion zone to thereby reduce NOx and carbon monoxide (CO) production in the combustion zone. In a further embodiment of the present invention, a combustor operating with a compressor to drive a gas turbine is comprised of an outer combustor wall having an upstream fuel entry end and a downstream turbine entry end, the outer combustor wall having a length between 35 inches and 50 inches; a plurality of rows of liner louver cooling holes positioned longitudinally along the combustor wall; a plurality of mixing holes located proximal to the upstream fuel entry end of the outer combustor wall; the plurality of dilution holes being located proximal to the plurality of mixing holes; the plurality of mixing holes being arranged in first and second rows which extend around a circumference of the outer combustor wall rather than first, second and third rows which extend around the circumference of the outer combustor wall so that the plurality of dilution holes are arranged in the third row from the upstream fuel entry end extending around the circumference of the outer combustor wall so as to be located within a distance of five inches to forty inches from the fuel entry end of the combustor wall; an outer shell; a nozzle from which compressed air and fuel are discharged into combustor; a flow sleeve located between the outer shell and the combustor wall so as to form a cavity between the outer shell and the combustor wall so that air from the compressor entering the combustor is divided between a first path by which a first part of the compressor air is admitted into the combustor by entering through the flow sleeve, and a second path by which a second part of the compressor air is admitted into the combustor through the cavity; and a plurality of pipes extending between the cavity and the plurality of dilution holes at an angle to thereby tangentially admit the second part of the compressor air into the combustion zone for increased mixing of the admitted air with combustion gases in the combustion zone, the angle at which the pipes enter the combustor being achieved using an offset of the pipes of zero to seven inches from the center of the combustor, the diameters of the plurality of dilution holes though which air from the plurality of pipes is passed into the combustor being increased to a dimension that results in an increase in air flow into the combustor combustion chamber, and the diameters of the plurality of louver cooling holes though which louver cooling air passes being reduced to a dimension that results in a further increase in mixing of the admitted air with combustion gases in the combustion zone to thereby reduce NOx and carbon monoxide (CO) production in the combustion zone. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 , which is a figure from U.S. Pat. No. 6,192,689, is a schematic representation of a portion of an industrial gas turbine engine having a low NOx combustor joined in flow communication with a compressor and turbine. FIGS. 2A and 2B are side elevational and perspective schematic representations, respectively, of a conventional combustor liner used in an industrial gas turbine engine. FIG. 3 is a perspective schematic representation of a combustor liner according to the present invention. FIGS. 4A to 4C show a first embodiment of a Dry Low NOx (“DLN”) combustion system incorporating the combustor liner shown in FIG. 5 . FIG. 5A to 5C show a second embodiment of a DLN combustion system incorporating the combustor liner shown in FIG. 5 . FIG. 6A to 6C show a third embodiment of a DLN combustion system incorporating the combustor liner shown in FIG. 5 . FIG. 7 is an end elevational representation of the angle at which the pipes enter the combustor in the embodiments of FIGS. 5A to 6C using a range of offsets of the pipes from the center of the combustor. FIG. 8 is a partial breakaway perspective view of part of a diffusion type combustor. FIG. 9A is a picture of a temperature field within the diffusion type combustor of FIG. 8 during operation with a conventional type liner like that shown in FIGS. 2A and 2B . FIG. 9B is a picture of a temperature field within the diffusion type combustor of FIG. 8 during operation with a type liner according to the present invention like that shown in FIG. 3 . FIG. 10A is a graph of the emissions inside and that exit a diffusion type combustor like that of FIG. 8 during operation with a conventional type liner like that shown in FIGS. 2A and 2B and with a type liner according to the present invention like that shown in FIG. 3 . FIG. 10B is a graph of the temperature inside and that exit a diffusion type combustor like that of FIG. 8 during operation with a conventional type liner like that shown in FIGS. 2A and 2B and with a type liner according to the present invention like that shown in FIG. 3 . DETAILED DESCRIPTION OF THE INVENTION FIG. 1 of U.S. Pat. No. 6,192,689 is a schematic representation of a portion of an exemplary industrial gas turbine engine 10 having a low NOx combustor 18 joined in flow communication with a compressor 12 and turbine 20 . The industrial gas turbine engine 10 includes a compressor 12 for compressing air 14 that is mixed with fuel 16 and ignited in at least one combustor 18 , as shown in FIG. 1 . A turbine 20 is coupled to compressor 12 by a drive shaft 22 , a portion of which drive shaft 22 extends for powering, for example, an electrical generator (not shown) for generating electrical power. During operation, compressor 12 discharges compressed air 14 that is mixed with fuel 16 and ignited for generating combustion gases 24 from which energy is extracted by turbine 20 for rotating shaft 22 to power compressor 12 , as well as for producing output power for driving the generator or other external load. Combustor 18 comprises a cylindrical combustor wall 26 , which defines a combustion chamber 28 cylindrical combustor wall 26 . FIGS. 2A and 2B are side elevational and perspective schematic representations, respectively, of a conventional combustor liner 30 used in an industrial gas turbine engine 10 . The combustor 30 includes a cylindrical combustor wall 32 having a fuel entry end 34 and a turbine entry end 36 . The combustor liner 30 includes a plurality of rows of liner louvers cooling holes 38 positioned longitudinally along the liner 30 and having different diameters at different positions along the liner 30 . The combustor liner 30 is also comprised of several sets of air holes disposed about its periphery. A first set of air holes 40 , referred to as mixing holes, supply a quantity of air to the reaction zone within combustion chamber 28 . The mixing holes 40 are disposed proximate to the fuel entry end 34 of combustor 30 to provide an entry for mixing air. The number of mixing holes 40 is variable, typically depending on the overall size of combustor 30 . A second set of air holes 42 are positioned at the downstream end of the combustion chamber to quench combustion gases 24 prior to entering a transition piece (not shown) or a turbine inlet (not shown). A second set of air holes 42 , called dilution holes, are disposed in a central region of the combustor 30 , closer to the downstream end of the combustion chamber 28 within combustor 30 . The dilution holes 42 provide an entry area for dilution air into to combustor 30 . The dilution air is provided to lower the temperature of combustion gases 24 prior to entering a turbine inlet (not shown) or a transition piece (not shown). The temperature field within combustor 30 during operation is such that temperatures are very high in the primary zone of combustor 30 , if water is not injected into combustor 30 , although it should be noted that temperatures drop along the length of combustor 30 . The formation of NOx within combustor 30 during operation is such that approximately 95% of the ppmvd@15% NOx has already been formed before the combustion gases 24 reach the dilution holes 42 . NOx formation rates are highest in a narrow zone, with not much of the NOx being formed after the dilution holes 42 in combustor 30 . Thus, the dilution holes' air does not participate in temperature and NOx reduction in conventional combustor 30 . In the present invention, combustion in a conventional combustor is changed from “rich” to “lean” to “rich” to “quench” to “lean” by changing the air entry arrangement of the conventional combustor. In the air entry arrangement according to the present invention, dilution holes are removed from the region of the combustor closer to the downstream end of the combustion chamber within combustor, liner cooling is reduced and air is admitted into the combustor at the third row of the mixing holes with the help of a plurality pipes arranged in a manner that causes air coming from the pipes to enter the combustor 30 as swirling flow in a direction opposite to nozzle swirl, so as to therefore produce a large mixing and quenching effect. In a preferred embodiment of the modified combustor according to the present invention, the plurality of pipes comprises six pipes. FIG. 3 is a perspective schematic representation of a combustor liner 50 according to the present invention. The combustor 50 includes a cylindrical combustor wall 52 having a fuel entry end 54 and a turbine entry end 56 . In the combustor 50 , the air entry arrangement has been changed so that dilution air is admitted into the combustor 50 closer to a fuel entry end 54 . The combustor wall 52 also has a plurality of rows of liner louver cooling holes 58 positioned longitudinally along the combustor 50 and having different diameters at different positions along the combustor 50 . Like the combustor shown in FIGS. 2A and 2B , the combustor 50 includes several sets of air holes disposed about its periphery. Here again, the combustor 50 includes a set of mixing holes 60 which are disposed proximate to the fuel entry end 54 of combustor 50 to provide an entry for a quantity of mixing air to be supplied to the reaction zone within the combustion chamber 28 . The combustor 50 also includes a set of dilution holes 62 . Again, the number of mixing holes 60 and the number of dilution holes 62 vary according to the overall size of combustor 50 . Like the combustor disclosed in U.S. Pat. No. 6,192,689, a preferred embodiment of the combustor wall 52 has a preferred nominal diameter (d) in the range between about 9 inches to about 15 inches and a preferred nominal length (L) in the range between about 35 inches to about 50 inches. In addition, the mixing holes 60 have a preferred diameter in the range between about 0.5 inches to about 1 inch, and the dilution holes 62 have a preferred diameter in the range between about 1.25 inches to about 4.0 inches. FIGS. 4A to 4C show a first embodiment of a Dry Low NOx (“DLN”) combustion system incorporating the combustor liner 50 shown in FIG. 3 . The DLN combustion system includes combustor liner 50 , a nozzle 51 from which compressed air 14 and fuel 16 that is mixed with the compressed air 14 is discharged into combustor 50 and a diverging cone 53 positioned between nozzle 51 and combustor 50 . An endplate 55 holds the body of the combustor 50 together. In the preferred embodiment shown in FIGS. 4A to 4C , the mixing holes 60 are preferably arranged in two rows, which extend around the circumference of the cylindrical combustor wall 52 , and which are proximate to the fuel entry end 54 of the cylindrical combustor wall 52 . The dilution holes 52 are arranged in a single row, which replaces a third row of mixing holes that would typically be present in a conventional combustor. The row of dilution holes 52 preferably extends around the circumference of the cylindrical combustor wall 52 , and is proximate to the two rows of mixing holes 60 in cylindrical combustor wall 52 so that dilution air is admitted into the combustor 50 proximate to the fuel entry end 54 of combustor 50 . In a preferred embodiment of the claimed combustor 50 , the dilution holes 62 are located within a range of 5 inches to 40 inches from the fuel entry end 54 of the combustor wall 52 . Thus, in the preferred embodiment shown in FIGS. 4A to 4C , part of the mixing holes 60 , i.e., those typically located in the third row of mixing holes are removed, and the number of dilution holes 62 is increased. Preferably, eight of the 24 mixing holes 60 in a conventional combustor, i.e., those holes in the third row of mixing holes, are removed, and the number of dilution holes 62 is increased from four typically in a conventional combustor to six to maintain jet penetration for mixing air to be supplied to the reaction zone within the combustion chamber 28 . Mid-frame air 64 from the compressor 12 continues to be admitted into the combustor 50 by entering through flow sleeve 66 within a shell 74 containing combustor 50 . FIG. 5A to 5C show a second embodiment of a DLN combustion system incorporating the combustor 50 shown in FIG. 3 . In the embodiment shown in FIG. 5A to 5C , the modified liner shown in the embodiment of FIGS. 4A to 4C is maintained. However, the embodiment shown in FIG. 5A to 5C also includes a modified cavity arrangement for much larger mixing of air with the combustion gases within the combustion chamber 28 . Thus, as in the embodiment of FIGS. 4A to 4C , the dilution holes 52 are again moved to the third row of mixing holes 50 in combustor wall 62 so that dilution air is admitted into the combustor 50 at the third row of mixing holes 50 , and, as such, the mixing holes 50 in the third row are removed. In the modified cavity arrangement, the mid-frame air 64 is divided into two paths, i.e., one path for a part of the mid-frame air 64 to continue to be admitted into the combustor 50 by entering through flow sleeve 66 , and another path for another part 68 of the mid-frame air 64 to flow through a cavity 70 between the flow sleeve 66 and the outer shell 74 , whereupon air flowing through the cavity 70 will tangentially enter the combustor 50 through a plurality of pipes 72 extending at an angle between the cavity 70 and the third row dilution holes 62 into the combustor 50 . The air 68 entering the combustor 50 tangentially through pipes 72 results in an increase in air mixing with combustion gases 24 in the combustor primary zone. The angle at which the pipes 72 enter the combustor 50 in a preferred embodiment is achieved using a range of offsets of zero to seven inches of the pipes from the center of the combustor 50 , as shown in FIG. 7 . The mixing is improved because air flowing from the pipes 72 flows counterclockwise to the air flowing from the nozzle 51 . FIG. 6A to 6C show a third embodiment of a DLN combustion system incorporating the combustor 50 shown in FIG. 5 . In the embodiment shown in FIG. 6A to 6C , the modified liner with relocated dilution holes, as shown in the embodiment of FIGS. 4A to 4C , is again used. In addition, the modified cavity arrangement for much larger mixing of air and combustion gases in the embodiment shown in FIG. 5A to 5C is again used. However, increased air flow of 10-15% is added to increase the penetration of air into the hot temperature zones in the combustion chamber 28 . This is achieved by increasing the size/diameter of the dilution holes 62 though which air from pipes 72 is passed into combustor 50 . Also, louver cooling air passing through the plurality of rows of louver cooling holes 58 in the combustor liner 50 is reduced by half from 25-35% of the mid-frame air flow 64 to 10-15% of the mid-frame air flow 64 by decreasing the size/diameter of the cooling holes 58 . It is noted that 25-35% louver cooling is an old design, in which the liner temperature can reach to 800° F. to 1000° F. in temperature. It should be noted that one alternative arrangement in which the larger dilution holes are used is one in which the mixing holes and larger dilution holes are arranged a single row located a distance from the fuel entry end 54 of the combustor liner 52 as would be the row of dilution holes 62 in the embodiment of FIGS. 3A to 3C would be. FIG. 8 is a partial breakaway perspective view of part of a diffusion type combustor 80 . The combustor includes an inlet nozzle 81 , a combustor liner 82 with a cylindrical combustor wall, and a flow sleeve 84 through which mid-frame air enters the combustor 80 . FIG. 9A is a picture of a temperature field within the diffusion type combustor 80 of FIG. 8 during operation with the liner 82 being a conventional type liner like that shown in FIGS. 2A and 2B . FIG. 9B is a picture of a temperature field within the diffusion type combustor 80 of FIG. 8 during operation with the liner 82 being of a type like that shown in FIG. 3 . As can be seen in FIG. 9B where a type of liner like that shown in FIG. 3 is used, the temperatures in the combustor 80 are less than those shown in FIG. 9A where a conventional type liner like that shown in FIGS. 2A and 2B is used. It can be seen from FIGS. 9A and 9B that the high temperature reaction zone within the combustion chamber 28 is reduced significantly after the dilution holes 62 have been moved closer to the fuel entry end 54 of the cylindrical combustor wall 52 , even though the exit profile of the combustor did not change much. FIG. 10A is a graph of the emissions inside and that exit a diffusion type combustor 80 like that of FIG. 8 during operation with a conventional type liner like that shown in FIGS. 2A and 2B and with a type liner according to the present invention like that shown in FIG. 3 . FIG. 10B is a graph of the temperature inside and that exit a diffusion type combustor like that of FIG. 8 during operation with a conventional type liner like that shown in FIGS. 2A and 2B and with a type liner according to the present invention like that shown in FIG. 3 . It can be seen from FIGS. 9A and 9B and the graph of FIG. 10B that the high temperature reaction zone within the combustion chamber 28 is reduced significantly after the dilution holes 62 have been moved closer to the fuel entry end 54 of the cylindrical combustor wall 52 , so that the diffusion type combustor 80 of FIG. 8 was operated a liner 82 of a type like that shown in FIG. 3 , even though the exit profile of the combustor did not change much. It can also be seen from the graph of FIG. 10A that the combustor 80 of FIG. 8 , when operated with a liner 82 of a type like that shown in FIG. 3 , reduces NOx emissions by approximately 65% and CO emissions by approximately 50% at the exit of combustor 80 . While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
An improved combustor is disclosed in which conventional combustion is changed to “rich to quench to lean” by changing the air entry arrangement in the liner of the combustor to remove mixing holes, reduce liner cooling and admit dilution air into the combustor liner in place of mixing air. In an alternative embodiment, dilution air is admitted into the combustor liner with the help of a plurality of pipes arranged so that air comes into the liner as a swirling flow in a direction opposite to nozzle swirl, so as to thereby produce a large mixing of air with the combustion gases and a resulting quenching effect, i.e., a rapid cooling of the combustion gases by quenching air. As such, the requirement for cooling water to quench the combustion gases is significantly reduced, thereby helping turbine efficiency and reducing turbine emissions.
5
FIELD OF THE INVENTION The present invention relates, to a method, apparatus and computer program for reducing the amount of data checkpointed in a data processing environment. BACKGROUND TO THE INVENTION Asynchronous transfer of messages between application programs running different data processing systems within a network is well known in the art, and is implemented by a number of commercially available messaging systems. These systems include IBM Corporation's MQSeries family of messaging products, which use asynchronous messaging via queues. A sender application program issues a PutMessage command to send (put) a message to a target queue, and MQSeries queue manager programs handle the complexities of transferring the message from the sender to the target queue, which may be remotely located across a heterogeneous computer network. The target queue is a local input queue for another application program, which retrieves (gets) the message from this input queue by issuing a GetMessage command asynchronously from the send operation. The receiver application program then performs its processing on the message, and may generate further messages. (IBM and MQSeries are trademarks of International Business Machines Corporation). Messaging products such as MQSeries provide for assured once and once-only message delivery of messages even in the event of system or communications failures. This is achieved by not finally deleting a message from storage on a sender system until it is confirmed as safely stored by a receiver system, and by the use of sophisticated recovery facilities. Prior to commitment of transfer of the message upon confirmation of successful storage, both the deletion of the message from storage at the sender system and insertion into storage at the receiver system are kept ‘in doubt’ and can be backed out atomically in the event of a failure. This message transmission protocol and the associated transactional concepts and recovery facilities are described in international patent application WO 95/10805 and U.S. Pat. No. 5,465,328. One key aspect of providing such an assured delivery of messages capability is the maintenance of a log in each system. A log is used to keep track of completed message activity and because a log is typically maintained a direct access non-volatile storage device (such as a hard disk drive), the information stored therein is permanently accessible. The log can therefore be used to recover the state of a system (i.e. queue(s) state) in the event of a failure thereof. Each time a recoverable message is sent to a queue, a record that the message was sent, including the message data, is written to the log, and each time a message is retrieved from a queue, a record that the message was retrieved is written to the log. In the event of a failure, the log is replayed to recover each queue to the state it was in at the point when the failure occurred. A queue's message throughput in such a system can however be high. Further a log may be recording message activity for more than one queue. Consequently a large number of operations may be written to the log and having to replay the whole log at restart would not be feasible (this may involve replaying millions of records). In order to avoid the need to replay the entire log at restart, the queue manager periodically writes consolidated queue manager state to disk. This process is known as checkpointing. The data written at checkpoint time allows the queue manager to restart using only data that was written to the log relatively recently. A checkpoint typically hardens the current state of all queues which have changed since the previous checkpoint to permanent storage (disk). FIGS. 1 a and 1 b illustrate a simplified view of logging and checkpointing according to the prior art. In FIG. 1 a the state of a queue is shown in steps 1 through 8 and FIG. 1 b illustrates the corresponding operations written to the log. At step 1 , messages A, B and C are put to a queue. This is recorded in the log (+A, +B, +C). An application then removes B from the queue (step 2 ) and this is reflected in the log (−B). Message D is subsequently added to the queue and so the queue now contains messages A, C and D (step 3 ). At this point the system takes a checkpoint by forcing the current state of the queue (as shown) to disk (step 4 ). A start checkpoint marker is placed in the log and only when checkpointing has completed is an end check point marker placed therein. Whilst checkpointing is taking place, messages continue to be put and got from the queue and these operations are recorded in the log between the start and end markers. Thus, at step 5 message E is added to the queue and the log (+E). A is then removed from the queue (step 6 ) and recorded in the log (−A). At step 7 , F is put to the queue and at step 8 C is removed from the queue. Once again this is all recorded in the log (+F, −C). At this point checkpointing finishes and the end checkpoint marker is placed in the log. Messages continue to be put and got from the queue and these operations recorded in the log (+G, −F). It is after F is got from the queue that the system fails and the current state of the queue (D E G) must be recovered. As previously mentioned the whole log could be replayed in order to return the queue to its lost state. However, this would involve a large number of operations and is wasteful of both time and processing power. Thus because the consolidated state written to disk at step 4 (e.g. A C D) is recoverable, the operations stored in the log need only be replayed from the start checkpoint marker to the end of the log. Thus in this instance, A, C and D are safely on disk and only six operations have to be replayed to restore the queue. This is instead of 11 operations if the log had had to be replayed from the beginning. Note, whilst FIG. 1 a shows A, C and D being forced to disk at step 4 , this is not necessarily the case. In reality what is forced to disk could be any queue state occurring between the start checkpoint marker and the end checkpoint marker. In any case checkpointing is well-known in the art and thus this should be understood by the skilled person. Obviously FIGS. 1 a and 1 b show a greatly simplified view of the processing that takes place. It will be appreciated that in reality the message throughput in a messaging system will typically be far greater and that as a result the number of operations logged will be far larger. Consequently checkpoints have to be taken relatively frequently and because checkpointing involves forcing I/O it is expensive, especially considering that failures are rare occurrences and thus the majority of checkpoint data written will never be called upon. SUMMARY OF THE INVENTION Accordingly the invention provides a method reducing the number of data elements (e.g. messages) checkpointed in a system (e.g. a messaging system) having at least one data store (e.g. queue), operations on said at least one data store being recorded in a log, the method comprising the steps of: recording a point in the log; determining the oldest data element in each of the least one data store; determining for each of the at least one data store whether a logged representation of the data store's oldest data element is more recent than the point recorded; and responsive to determining that a data store's logged representation is more recent than the point recorded, realising that it is not necessary to force data elements from that data store to disk if the point recorded is made the point of restart (e.g. in the event of a failure) for that data store. Checkpointing involves forcing I/O and so is expensive. Failures are rare occurrences and so the majority of checkpoint data written will never be called upon. Any way of lessening the amount of data checkpointed is useful and if the oldest of a data store's data elements is more recent in the log than the point recorded, then all data elements in the store are recoverable if the log is replayed from this point. The term disk as used herein with reference as to whether data elements are forced thereto or otherwise, should be taken to mean a data store from which the forced data elements can be recovered. In a preferred embodiment, responsive to deciding not to force data elements as a result of determining that it is not necessary to do so, making the point recorded the point of restart for that data store. In one embodiment, responsive to determining that a data store's logged representation is older than the point recorded, data elements from that data store are forced to disk and the point at which data elements were forced is made the point of restart for that data store. In another embodiment, responsive to determining that a data store's logged representation is older than the point recorded, this recorded point is made the point of restart for that data store and data elements from the data store are forced to disk. In one embodiment the point of system restart, in the event of a failure, is the point recorded. The point of restart is preferably determined for each data store. Further preferably the oldest restart point of all the data stores is determined and this oldest restart point is made the system restart point (e.g. in the event of a failure). In one embodiment, the step of determining the oldest data element in the at least one data store is responsive to determining that according to at least one predetermined criterion it is time to take a checkpoint. One criterion might be that the log is p % full; x operations have been carried out; or m minutes have passed. In one embodiment, the point recorded is the point at which it is determined that it is time to take a checkpoint and the step of determining the oldest data element in each of the at least one data store is responsive to waiting a predetermined period of time over and above time at which the point is recorded. In one embodiment, a plurality of points, subsequent to a previous system restart point in the log, are recorded. It is determined for each of the at least one data store whether a logged representation of the data store's oldest data element is more recent than any of the recorded points and responsive to determining that a data store's logged representation is more recent than at least one of the recorded points, it is realised that it is not necessary to force data elements from that data store to disk if the newest (most recent) of said points is made the restart point for that particular data store. In one embodiment, responsive to deciding not to force any data elements for that data store as a result of realising that it is not necessary to do so, the newest of the points is made the restart point for that particular data store. If no such point is found for a data store, the point at which the data store's data elements was forced to disk may be made the point of restart for that data store. The other embodiment provides a higher chance that data elements will not have to be forced to disk. This is because there is more than one point against which the oldest message in a data store is compared. Preferably a new restart point is determined for all data stores in the system (i.e. a restart point that ensures data integrity for the whole system in the event of a failure). This may involve making the earliest data store restart point, the system restart point. Alternatively the system restart point may be the newest recorded point for a predetermined number of data stores where a logged representation of the oldest data element in each of those data stores is more recent than this point. In this instance, the data elements in all other data stores are preferably forced to disk. In one embodiment, responsive to determining that a data store has fewer than a predetermined number of data elements therein, that data store's data elements are forced to disk and the point at which the data elements are forced is made the point of restart for that data store. This may be done because forcing a relatively small amount of data to disk is acceptable and allows the point of restart for that data store (and potentially for the whole system) to progress. In another embodiment, it may be possible to advance the system restart point. This may be achieved by recording, for each data store, when a data element is put to an empty data store (this provides a known state). It is then determined whether at least one empty data store point is more recent than the system restart point. From such at least one more recent empty data store point, the newest empty data store point for which a representation of the oldest data element in each of a predetermined number of data stores is more recent, is determined. The determined empty data store point, is made the system restart point. The predetermined number of data stores may be all data stores. However, if this is not the case then the data elements of any other data stores are preferably forced to disk. In one embodiment each data store has storage associated therewith, the storage indicating the oldest data element in the associated data store, and wherein the step of determining the oldest data element in each of the at least one data store comprises using the storage associated with the appropriate data store. This provides a quick and easy way of determining the oldest data element in a store. According to another aspect the invention provides an apparatus for reducing the number of data elements checkpointed in a system having at least one data store, operations on said at least one data store being recorded in a log, the apparatus comprising: means for recording a point in the log; means for determining the oldest data element in each of the least one data store; means for determining for each of the at least one data store whether a logged representation of the data store's oldest data element is more recent than the point recorded; and means, responsive to determining that a data store's logged representation is more recent than the point recorded, for realising that it is not necessary to force data elements from that data store to disk if the point recorded is made the point of restart for that data store. According to another aspect, the invention provides a method for reducing the number of data elements checkpointed in a system having at least one data store, operations on said at least one data store being recorded in a log, the method comprising the steps of: recording a plurality of points in log; determining for each of the at least one data store whether a logged representation of the data store's oldest data element is more recent than any of the recorded points; and responsive to determining that a data store's logged representation is more recent than at least one of the recorded points, realising that it is not necessary to force data elements from that data store's logged representation to disk if one of said at least one points (preferably the newest) is made the restart point for that particular data store. According to another aspect, the invention provides an apparatus for reducing the number of data elements checkpointed in a system having at least one data store, operations on said at least one data store being recorded in a log, the apparatus comprising: means for recording a plurality of points in log; means for determining for each of the at least one data store whether a logged representation of the data store's oldest data element is more recent than any of the recorded points; and means, responsive to determining that a data store's logged representation is more recent than at least one of the recorded points, for realising that it is not necessary to force data elements from that data store's logged representation to disk if one of said at least one points (preferably the newest) is made the restart point for that particular data store. The invention preferably provides a quick and easy way of determining whether it is necessary to force data to disk based on the position of a data store's data relative to a recorded point, of course, despite it not being necessary to force data in some situations, the system may still choose to do so (for example, in order to progress a restart point). It will be appreciated that the invention may be implemented in computer software. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present invention will now be described by way of example only and with reference to the following drawings: FIGS. 1 a and 1 b illustrate a simplified view of logging and checkpointing according to the prior art; FIGS. 2 a , 2 b and 2 c illustrate processing according to a first embodiment of the present invention; FIGS. 3 a , 3 b and 3 c illustrate processing according to a second embodiment of the present invention; DETAILED DESCRIPTION As discussed above, checkpointing is an expensive process. A failure is typically a rare occurrence and so much of the data checkpointed is never used. It has been observed that the majority of queues in a messaging system hold messages very transiently (only until the messages can be forwarded to their intended destination) and that it is therefore extremely likely that by the time a checkpoint has been taken (or very shortly afterwards), the messages forced to disk as a result of that checkpoint no longer exist on the relevant queue (i.e. the state information is out of date). This observation has permitted an improvement to the whole process which reduces the amount of data that is forced to disk during a checkpoint. A first embodiment of the present invention is described with reference to FIGS. 2 a ; 2 b and 2 c . A checkpoint is typically taken every x operations; m minutes; or when the log is a p % full. It is determined at step 100 of FIG. 2 a that according to one of the aforementioned criteria it is time to take a checkpoint and this is marked in the log (CP marker). (At this point ( 160 ) the queue of FIG. 2 b has messages A; C; and D on it.) However, instead of actually forcing data to disk the system waits a preconfigured period of time (step 110 ). Operations continue to be written to the log during this time period (+E −A+F −C −D) and having waited the appropriate amount of time, the system checks the queue for the oldest recoverable message (step 120 ). The position of this message in the log then determines whether or not the state of the queue needs to be forced to disk (e.g. the state shown at 160 of FIG. 2 b ). Each queue has a queue control block (QCB) and FIG. 2 c shows how this is used to determine where in the log the oldest message on the queue sits (step 130 ). Messages are typically added to a queue in a first in first out (FIFO) order. Thus the newest message on the queue is at the tail of the queue and is pointed to by a tail field in the QCB. The oldest message on the queue is at the head and is pointed to by a head field in the QCB. The QCB also has a next sequence number field. Each message on a queue is assigned a sequence number in a monotonically increasing order and a message's number can be discovered by examining that message. (Note, sequence numbers are only unique within a queue). The next sequence number field in the QCB is used to allocate a new sequence number to each message (one is added to the previous sequence number allocated). At the point of placing the CP marker in the log (i.e. step 100 ) the system makes a note of the next sequence number that it is going to allocate to a message on the relevant queue in a start checkpoint sequence number field of each QCB. In order to determine whether the oldest message on a queue is older, or more recent than the point at which a CP marker was placed in the log, the head field's pointer is used to find the oldest message on the queue. This message can then be examined to determine its sequence number and this number is compared with the sequence number in the start checkpoint sequence number field of that queue's QCB. If the two are equal, or if the oldest message's sequence number is greater, then all the messages on the queue are more recent than the CP marker and are therefore easily recoverable. In this instance, there is no need to force any data to disk during the checkpoint (step 140 ). This is because none of the messages on the queue at the beginning of the preconfigured time period are still on the queue at the end of that time period. With the example shown in FIG. 2 b messages A C and D ( 160 ) have all been removed from the queue by the time the system makes the decision as to whether to force the queue's state to disk. The queue now has only messages E and F thereon ( 170 ). Since the oldest message on the queue E is more recent than the CP marker, there is no need to force any data to disk. The CP marker becomes the point at which the log is replayed from (i.e. the point of restart) in the event of a failure. On the other hand, if the oldest message is less recent than the CP marker, then it is not easily recoverable. In this instance the current state of the queue does need to be forced to disk such that it is readily available in the event of a system failure. It should be appreciated from the above that systems generally have more than one queue and thus in the prior art data is typically forced to disk during a checkpoint for each queue. According to the present invention, it is preferably necessary to check the position of the oldest recoverable message on each queue relative to the CP marker to determine whether data for that queue needs to be forced to disk. At restart all records forward of the CP marker are replayed to restore the system to the state it was in at the time of system failure. An alternative to marking the log with a CP marker and waiting a preconfigured period of time, is to remember a point in the log (not necessarily mark it) a certain amount prior to the point at which a checkpoint is typically taken. (Log records are allocated log sequence numbers (LSNs) and it is an LSN that is remembered. LSNs are described below.) Whether any data is forced at that checkpoint depends on the position of the oldest message on each queue relative to the point remembered. The point remembered is the point of restart for the system. FIGS. 3 a ; 3 b ; and 3 c show processing according to a second embodiment of the present invention. Each record in the log is referenced by a log sequence number (LSN). Every x operations/m minutes in the log, the next LSN to be allocated is stored in an array of LSN ( FIG. 3 c ). As before each queue has a QCB associated therewith, but in this instance each QCB has an array for message sequence numbers SO through to Sn. Just after each LSN is recorded in the LSN array, the next sequence number to be allocated to a message put to a queue is stored in this array. Thus each sequence number array element maps to a system wide Log Sequence Number (LSN) array element (point in the log). (Once again each QCB has a next sequence number field from which each message sequence number is allocated.) At step 200 it is determined that it is time to take a checkpoint. (Note, there is no need to actually mark this point in the log for recovery purposes, although a marker might still be useful for other reasons.) At step 210 , the system looks for a queue's oldest message. The sequence number associated with this oldest message is then compared with values stored in the sequence number array to find the number nearest but not greater than the oldest message sequence number. Using the LSN array, this number can then be mapped to an LSN which would allow that queue to be restarted without any data having to be forced to disk (step 220 ). This process is then repeated for each queue to determine a notional point of restart for each queue (steps 230 ; 210 ). (Note, as before a message sequence number is only unique within a queue and as with message sequence numbers, LSN's are allocated in a monotonically increasing order.) Having determined a notional point of restart for each queue (queue restart LSN) and stored this in the relevant queue's QCB, a restart LSN has to be determined for the whole system (system restart LSN) (step 240 ). This is the point in the log that would give data integrity following a system failure (i.e. the lowest queue restart LSN). The relevant LSN is therefore made the system restart LSN for the whole system and is stored in the system restart LSN field ( FIG. 3 c ). For some queues data may need to be forced to disk. The rule is that the point of restart for the system must always progress forwards in the log from a previous system wide restart point (see below). Thus if a queue's (queue A) oldest message is older than a previous checkpoint, then its data is not easily recoverable and its state is therefore hardened to disk. Having hardened queue A's data, the restart point for queue A will be the point at which the data was forced. Note, if queue A's point of restart has still not progressed at the subsequent checkpoint, then that queue's data will have to be hardened to disk once more. Determining which queues to harden and which LSN is to be the system restart LSN may in another embodiment take a number of other factors into account. For example, the system restart LSN may be determined by the LSN which would allow restart for the majority of queues without forcing to disk being necessary. With certain queues, it may be determined that the amount of data thereon is only small and so forcing to disk is not a problem. An additional minor enhancement will now be described which is applicable to both embodiments described. Again due to the transient nature of message, the state of an active queue typically oscillates frequently between empty and non empty (unlike a database where it is rare for a database to ever be empty). It has been observed that an empty queue also provides a known state from which recovery can be attempted. This fact can thus be used to progress the point of restart in the log yet further. Every time a message is put to an empty queue its sequence number is recorded and mapped to an LSN used to record that operation in the log is recorded in an QCB array for that queue (Empty.LSN). It is determined whether one queue's Empty.LSN would progress the point of restart forward, whilst still allowing all the other queues to restart from the progressed point with data integrity. In other words, the relevant Empty.LSN must be more recent than the current system restart LSN but older than the oldest message on the majority (or all) queues. For example, in the first embodiment if the sequence went +A+B+C CP −A −B −C+E+F. E is the oldest message on the queue and is more recent than the CP marker so is therefore recoverable without data needing to be forced to disk. The CP marker is the point of restart as previously described. However, E was put to an empty queue thus the point of restart can actually be progressed to this point. Of course, it may be determined that in order to progress the point of restart further some queues have to have their data forced to disk (where they wouldn't have needed to before). This is a trade-off that may be worth making. One of the effects of this invention according to the embodiments described is that the restart point may be earlier than it would have been if all of the new queue data had been hardened at every checkpoint. This could cause increased restart times. However it can also be argued that the reduced checkpoint costs allow checkpoints to be taken more often thereby reducing restart times. Note, the restart process itself following a failure is unchanged from prior art methods and will therefore be obvious to one skilled in the art. It should be appreciated that although the present invention is described in the context of a messaging system, no such limitation is intended. The invention is applicable to any environment in which checkpointing is used.
The invention relates to a method, apparatus and computer program for reducing the number of data elements checkpointed in a system having at least one data store where operations on said at least one data store are recorded in a log. A point in the log is recorded. The oldest data element in each of the least one data store is determined and it is then determined for each of the at least one data store whether a logged representation of the data store's oldest data element is more recent than the point recorded. Responsive to determining that a data store's logged representation is more recent than the point recorded, it is realised that it is not necessary to force data elements from that data store to disk if the point recorded is made the point of restart for that data store.
6
CROSS-REFERENCE TO RELATED APPLICATION This is a continuation-in-part application of the original U.S. application Ser. No. 07/563052 filed Aug. 6, 1990, now abandoned. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a method of operating a heat pump for the purpose of acquiring a high-temperature fluid that is a high quality fluid, such as steam, boiling water, etc. More particularly, this invention provides a method of operating a heat pump characterized by utilizing effectively a subcool region of a condenser. 2. Prior Art Heat pumps are utilized in a wide variety of applications for heat or cold, for example, refrigeration systems, space cooling or heating systems, hot water heating, etc. High temperature heat such as heat of steam or boiling water is a high quality energy since storage of such heat is enabled with a high density, an installation (e.g. room heater) for the receipt of heat can be miniaturized, radiant space heating that is silent and moderate is possible, its application range is significantly enlarged because of its sterilizing ability, drying ability, cleaning ability, etc. Consequently, a technology of acquiring heat of such a high temperature efficiently with a heat pump is earnestly expected from many fields. A major problem with heat pumps is that it is difficult to obtain heat of a high temperature and consequently, how we can attain a highest possible output temperature has been a matter of great concern. Many attempts have been made to that end, but a high temperature on the order of 70°-80° C. at the utmost has been attained. Attempts to attain such a high temperature include, for example, a method of collecting selectively and efficiently super heat of condensers which are each of a counterflow, single path type (Brit. Patent No. 1 559 318), or a heat pump system comprising counterflow type multiple condensers operating at different multiple pressure levels and multiple expansion means (WO 83/04088). These known methods are aimed at high temperature of 160°-200° F. (ca. 71°-93° C.), but actually acquired is heat of 180° F.(82° C.) at maximum while cold is rejected. Thus, it has not been possible, so far, to obtain a high-temperature fluid elevated to 100° C. such as boiling water or steam. A general heat pump having a single circuit shown in FIG. 1b and its operation will be described with reference to FIG. 5a and FIG. 5b: In an evaporator 4, refrigerant is evaporated at a definite temperature, extracting heat (from fluid to be cooled). When the evaporation is finished (e-f), dry saturated vapor is sucked and compressed with a compressor 1 and delivered at elevated pressure and temperature into a condenser 2 (f-a). The refrigerant vapor at an inlet of the condenser 2 is in superheated state and when a saturated vapor temperature is reached (a-b), liquefaction and condensation begin. The refrigerant is liquefied and condensed as it is cooled by a fluid to be heated (cooling water) until the refrigerant becomes saturated liquid and the condensation is completed (b-c). The liquid refrigerant is further subcooled (c-d) and passed through an expansion valve 3, and thereafter flows back into the evaporator 4 at lowered pressure and temperature (d-e). Thus, a refrigeration cycle is formed, wherein in the evaporator 4 the fluid to be cooled is changed into cold fluid giving up heat to the refrigerant whereas in the condenser 2 the fluid to be heated is changed into hot fluid extracting heat from the refrigerant. The enthalpy change during the refrigeration cycle is shown in a Mollier chart of FIG. 5b and the heat exchange between the refrigerant and the fluid in the condenser is shown in FIG. 5a. The heat pump operation is also true with a binary heat pump illustrated in FIG. 1a, which comprises a low-temperature stage circuit for circulation of a refrigerant including a compressor 11, an evaporator 14, an expansion valve 13, a cascade condenser/evaporator 22; and a high-temperature stage circuit for circulation of another refrigerant including a compressor 1, the cascade condenser/evaporator 22, an expansion valve 3 and a condenser 2, both circuits being interconnected in a heat exchangeable manner through the cascade condenser/evaporator 22, whereby a fluid to be heated can be discharged as a hot fluid from the condenser 2 and cold fluid can be discharged from the evaporator 14. For the high-temperature stage circuit, a higher-boiling-point refrigerant such as 1,1,2-trichloro-1,2,2-trifluoroethane (flon R-113), s-dichlorotetrafluoroethane (flon R-114), trichlorofluoromethane (flon R-11), etc. may be used whereas for the low-temperature stage circuit, a lower-boiling-point refrigerant such as dichlorodifluoromethane (flon R-12), chlorodifluoromethane (flon R-22), etc. may be used. In this manner, conventional refrigeration systems have been operated so as to ensure a certain amount of subcool degree in order to make the expansion valve operative without impairment, and the subcool degree necessitated to cause the expansion valve to act normally is currently considered to be as low as 3°-5° C. at the utmost. A superheat degree varies depending upon the kind of refrigerant, but usually is larger than a subcool degree. Most condensers have each had a maximum heat transfer coefficient in the saturated refrigerant region and significantly lower heat transfer coefficients in the superheat and supercool regions, and consequently, no attempt to utilize heat transfer characteristics of supercool region has been made and considered. If it is intended to take advantage of supercool degree, the condenser to be used will be too large in size with the result that not only is its economic merit reduced, but also an increased pressure loss owing to the condenser of large size reduces the coefficient of performance. Of conventional heat exchangers for condensers, those of a shell and tube type, a parallel-flow type, a crossflow type, a circulation-counterflow type, a mixed flow type, etc. have been of no use since they cannot sufficiently cool the refrigerant. Thus, the utilization of heat transmission characteristics of a supercool region has involved many obstacles and consequently, has never been taken into account or has been deemed impossible. In view of the prior art problems above, this invention is aimed at providing a method of operating a heat pump with which it is possible to acquire a high-temperature fluid of 100° C. or more which is a high-quality fluid, such as steam (ca. 120°), boiling water (ca. 100°C.), etc. as well as relatively high-temperature water of 70°-100° C. More specifically, a primary object of this invention is to provide a method of operating a heat pump which enables it to discharge a high-temperature output fluid, with a maximal fluid temperature difference between the output and input temperatures being 80°-100° C. To that end, the invention is designed to realize the foregoing object through a single condenser without using a large-size condenser or mutliple condensers. With a view toward attaining the object, the invention has taken a theoretical approach by newly considering the factor of a temperature effectiveness of refrigerant, which gives a measure of supercool degree, as defined by the formula: ##EQU2## We have investigated into the possibility of attaining efficiently an optimal high supercool degree that is much higher than ever while making the temperature difference between the saturated refrigerant temperature and inlet temperature of the fluid to be heated as large as possible and into requisites of a condenser that permit such a high supercool degree. As a result, the invention has been accomplished by finding a heat pumping method of utilizing efficiently a supercool region of a condenser, whereby it is possible to discharge a high-quality high-temperature fluid. BRIEF DESCRIPTION OF THE INVENTION This invention resides in a method of operating a heat pump having at least one circuit including a compressor, a condenser as a high-temperature heat output means, an expansion valve and a low-temperature heat output means interconnected for circulation of a refrigerant, which method comprises using, as the condenser, a heat exchanger of a complete counterflow, once-through path type to a fluid to be heated, said condenser having concentrical double tubes; and choosing a supercool degree, which is equal to the difference between a saturated refrigerant temperature and an outlet temperature of refrigerant, to satisfy the conditions that a temperrature effectiveness of refrigerant liquid defined by the formula: ##EQU3## is at least 40% and the temperature difference between saturated refrigerant temperature and inlet temperature of fluid to be heated is at least 35° C. In the formula above, it is natural that the outlet temperature of refrigerant must be higher than the inlet temperature of fluid to be heated. The aforementioned low temperature output means may be either an evaporator (single-circuit system), or a low-temperature segregated circuit including a compressor, an expansion valve, a cascade condenser-evaporator and an evaporator interconnected in a heat exchangeable manner with the high-temperature heat output circuit through the cascade condenser-evaporator (two circuit system) or multiple circuits having two or more segregated circuits (multiple-circuit system). In gaining a highest possible temperature fluid or both high-temperature fluid and cold fluid, a two-circuit or multiple-circuit heat pump is preferably adopted. With a single-circuit heat pump, it is preferable to use a higher-boiling-point refrigerant. The once-through path, complete counterflow type condenser to be employed in this invention is formed of a concentrical double-tube heat exchanger comprising an outer tube and an inner tube having corrugated wire fins, in which fluid to be heated is routed through the inner tube in an once-through path and refrigerant is routed through between the inner and outer tubes in a counterflow manner to the former. The fluid to be heated includes, for example, water of 0°-30° C., waste heat (up to 40° C.), etc. According to the operation method of this invention, owing to the measure of choosing a supercool degree, it is easy to set and control the operational conditions of a condenser with different kinds of refrigerants. That is, it is possible to choose an optimal high supercool degree determined by the conditions above for an intended or desired high temperature of output fluid thereby to discharge a high-temperature fluid of approximately 100° C. or more, e.g. boiling water (ca. 100° C.) or steam (ca. 120° C.), and relatively high temperature water of 70°-100° C., etc. with a large temperature difference of 80°-100° C. at maximum to 50° C., while attaining a high coefficient of performance. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1a nd FIG. 1b are diagrammatic layout views of a two-circuit heat pump and a single-circuit heat pump, respectively, with which the method of this invention can be performed. FIG. 2a, FIG. 2b and FIG. 2c are a plan view, a side elevational view and a fragmentary enlarged view, respectively, of one example of a concentrical double-tube condenser for use in the heat pumping method of the invention. FIG. 3a and 3b are a diagram of heat interchange in a condenser and a Mollier diagram, respectively, obtained by one example of this invention applied to a two-circuit heat pump. FIG. 4a and FIG. 4b are diagrams similar to FIGS. 3a and 3b resulting from another example of this invention applied to a single-circuit heat pump, FIG. 4a being a diagram of heat interchange in its condenser and FIG. 4b being a Mollier diagram. FIG. 5a and FIG. 5b are diagrams resulted from a conventional heat pumping method, FIG. 5a being a diagram of heat interchange in a condenser and FIG. 5b being a Mollier diagram. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The invention will be hereinbelow described in more detail by way of preferred embodiments with reference to the accompanying drawings. The method of this invention can be performed with a single-circuit heat pump, or a two-circuit or multiple-circuit heat pump, depending upon the kind of refrigerant used. For instance, a two-circuit heat pump as shown in FIG. 1a can be used, which comprises a low temperature stage circuit for circulation of a lower-boiling-point refrigerant including an evaporator 14 having a once-through path for a fluid to be cooled, an accumulator 15, a compressor 11, a cascade condenser-evaporator 22 and an expansion valve 13 connected in the order mentioned; and a high-temperature stage circuit for circulation of a higher-boiling-point refrigerant including the cascade condenser-evaporator 22, an accumulator 5, a compressor 1, a complete counterflow type condenser 2 having once-through path for fluid to be heated and an expansion valve 3 connected in the order mentioned, whereby two segregated circuits are interconnected through the cascade condenser-evaporator 22 in a heat exchangeable manner. A single-circuit heat pump that can be also used for this invention comprises, as shown in FIG. 1b, an evaporator 4, an accumulator 5, a compressor 1, a complete counterflow type condenser 2 having a once-through path for fluid to be heated and an expansion valve 3 interconnected for circulation of a refrigerant. In either case, it is essential to this invention that the fluid to be heated be routed through the condenser 2 from an inlet 6 to an outlet 7 thereof in once-through path, in complete counterflow to the refrigerant flow. To that end, the condenser 2 is, as illustrated in FIGS. 2a to 2c, constructed of a concentrical double-tube 30 comprising an outer tube 31 and a corrugated inner tube 32 having wire fins 33. Examples of the heat pump cycle resulted from this invention, particularly, the process of change of state of the refrigerant (on the high-temperature circuit side) can be seen from Mollier diagrams of FIG. 3b and FIG. 4b whereas temperature gradients of both fluids in the condenser are apparent from FIG. 3a and FIG. 4a. The refrigerant in superheat state (A) delivered from the compressor 1 to the inlet of the condenser 2 becomes saturated gas (B) during which time the enthalpy is changed from i 1 to i 2 ; the gas refrigerant is, upon cooling by water (fluid to be heated), liquefied and condensed at a constant pressure to be saturated liquid (C), during which time the enthalpy is changed to i 3 ; the liquid refrigerant is supercooled (D) at the outlet 7 of the condenser 2, reaching an enthalpy of i 4 . Then, the refrigerant is subjected to throttling expansion (D to E) through the expansion valve 3 to flow into the cascade condenser-evaporator 22 or evaporator at in the same enthalpy of i 4 =i 5 ; and there, the refrigerant is evaporated completely (E to F) at a lower pressure during which time the enthalpy is changed to i 6 . The refrigerant having an enthalpy of i 6 is then sucked into the compressor 1, and a heat pump cycle is thus formed. From the comparison between FIG. 3 or FIG. 4 (this invention) and FIG. 5 (prior art), it will be apparent that a significantly large supercool degree (C to D) and a significantly large temperature gradient of water between the outlet (t w2 ) and inlet (t w1 ) of the condenser 2 are obtained as compared with the case of conventional heat pump. In the case of a two-circuit heat pump, fluid to be cooled supplied from an inlet 8 of the evaporator 4 is preferably routed through the evaporator in counterflow to the refrigerant flow; and the higher-boiling point refrigerant and lower-boiling-point refrigerant are preferably flowed through the cascade condenser-evaporator 22 in counterflow manner. Examples of this invention will be shown below. EXAMPLE 1 Two-stage heat pump installation as illustrated in FIG. 1a was operated by the use of a condenser having a double-tube construction shown in Table 1 below, water as both fluids and flon R-114 and R-22 as refrigerants for high-temperature and low-temperature stages, respectively, under the conditions given in Table 2 below. Physical data are also shown in Table 2. TABLE 1______________________________________Heat Transfer Tube Wire Fin Corrugated Tube______________________________________Outer Tube (Diameter) 25.4.sup.OD × .sup.t 1.2 × 23.0.sup.ID mmInner Tube (Diameter) 12.7.sup.OD × .sup.t 1.7 × 11.3.sup.ID mmLength 3634 mHeat Transfer Area 0.154 m.sup.2Corrugation Pitch and Depth 4.67 mm; 0.21 mmHeight and Pitch of Wire Fins 0.8 mm; 0.48 mm______________________________________ TABLE 2______________________________________ Condenser Super- Super- heat Saturation cool Region Region Region______________________________________Heat Exchanger Duty*(kcal/h) 9552Condenser Inlet Temp. of Water 19.1(°C.)Condenser Outlet Temp. of 98.7Water (°C.)Condenser Outlet Temp. of 59.5Refrigerant (°C.)Saturation Temp. of Refrigerant 112(°C.)Superheat Degree (°C.) 7.1Supercool Degree** (°C.) 52.5Flow Rate of Water (liter/h) 120Flow Rate of Refrigerant (kg/h) 275.3Quantity of Heat (kcal/h) 496 5122 3937Overall Heat Transfer 1131 3260 1246Coefficient (kcal/m.sup.2 h °C.)Heat Transfer Coefficient on the 1449 10859 1929Refrigerant Side(kcal/m.sup.2 h °C.)Heat Transfer Coefficient on the 5671 5124 3873Water side (kcal/m.sup.2 h °C.)Percentage of Heat Transfer 17.4 34.1 48.5Area (%)______________________________________ Notes: *Heat Exchanger Duty = Flow Rate of Water × (Outlet Temp. of Water Inlet Temp. of Water) **Supercool Degree = Saturation Temp. of Refrigerant - Outlet Temp. of Refrigerant Pressures and temperatures in the change of state of the refrigerant (R-114) in the high-temperature cycle were measured, and enthalpy values as plotted in the Mollier diagram of FIG. 3b were obtained. The results are shown in Table 3 below, in comparison with the case of conventional heat pump cycle. TABLE 3______________________________________ StateThis Invention A B C D E F______________________________________Temperature (°C.) 119.1 112 112 59.5 35 78Pressure (kgf/cm.sup.2) 18.2 18.2 18.2 18.2 3.0 3.0Enthalpy (kcal/kg) i.sub.1 i.sub.2 i.sub.3 i.sub.4 i.sub.5 i.sub.6 148.8 147.0 128.4 114.1 114.1 145.4______________________________________ StateConventional a b c d e f______________________________________Temperature (°C.) 119.1 112 112 107 35 78Pressure (kgf/cm.sup.2) 18.2 18.2 18.2 18.2 3.0 3.0Enthalpy (kcal/kg) i'.sub.1 i'.sub.2 i'.sub.3 i'.sub.4 i'.sub.5 i'.sub.6 148.8 147.0 128.4 127.1 127.1 145.4______________________________________Notes:The symbols of "A" to "F" and "a" to "f" correspond tothe Mollier diagrams of FIG. 3b and FIG. 5b,respectively.From Table 3 above, the following values are calculated. Supercool Temperature Degree *1 Effectiveness *2 COP *3______________________________________This Invention 52.5° C. 56.5% 10.2Conventional 5° C. 5.4% 6.4Notes:*1 Supercool Degree = T.sub.C - T.sub.D or T.sub.c - T.sub.d ##STR1## ##STR2##From Table 3, it will be apparent that the enthalpy difference of therefrigerant liquid upon subcooling is greater in this invention than in Further, the relation between supercool degree of the refrigerant (R-114) in the condenser and coefficient of performance was examined, and the results obtained are given in Table 4 below. The measurement conditions are as follows: Saturation Pressure : 18.2 kgf/cm 2 Saturation Temperature (T C ) : 112.0° C. Inlet Temperature of Water (t w1 ) : 19.1° C. Enthalpy at Compressor Inlet (i 6 ) : 145.4 kcal/kg Enthalpy at Compressor Outlet (i 1 ) : 148.8 kcal/kg TABLE 4______________________________________ Outlet Enthalpy of Temp. RefrigerantTemperature Supercool of Refrig- Liq. at Out- CoefficientEffective- Degree *2 erant Liq. let i.sub.4 of Perfor-ness *1 (%) (°C.) T.sub.D (°C.) (kcal/kg) mance *3______________________________________ 5 4.6 107.4 127.1 6.410 9.3 102.7 125.6 6.820 18.6 93.7 122.9 7.630 27.9 84.1 120.4 8.440 37.2 74.8 118.0 9.150 48.4 65.6 115.7 9.760 55.7 56.3 113.4 10.470 65.0 47.0 111.1 11.180 74.3 37.7 108.9 11.7______________________________________ Notes: ##STR3## *2 Supercool Degree = T.sub.C - T.sub.D = 112 - T.sub.D - ##STR4## At the outlet of the condenser 2, boiling water of ca. 99° C. was discharged with a temperature difference of ca. 80° C. whereas at an outlet 19 of the evaporator 14, cold water of 7° C. was obtained with a temperature difference of 5° C. EXAMPLE 2 A heat pump installation as shown in FIG. 1b was run by using dichlorofluoromethane (r-12) as refrigerant, a condenser of the construction shown in Table 5 below and water as both fluids, under the conditions in Table 6 below. The resulting data are also shown in Table 6. TABLE 5______________________________________ Wire Fin Corrugated TubeHeat Transfer Tube (Double-tube)______________________________________Outer Tube (Diameter) 31.8.sup.OD × .sup.t 1.6 × 30.2.sup.ID mmInner Tube (Diameter) 19.05.sup.OD × .sup.t 0.95 × 17.15.sup.ID mmLength 3520 m × 4Heat Transfer Area 0.84 m.sup.2Corrugation Pitch 7.2 mmCorrugation Depth 0.31 mmHeight of Fins 0.8 mmFin Pitch 0.48 mm______________________________________ TABLE 6______________________________________ Condenser Super- Super- heat Saturation cool Region Region Region______________________________________Heat Exchanger Duty(kcal/h) 13630Condenser Inlet Temp. of Water 20.4(°C.)Condenser Outlet Temp. of Water 96.2(°C.)Saturation Temp. (°C.) 84.6Superheat Degree (°C.) 50.6Supercool Degree (°C.) 46.6Flow Rate of Water (liter/h) 180Flow Rate of Refrigerant (kg/h) 303.9Quantity of Heat (kcal/h) 3370 6470 3790Difference between Outlet Temp. 18.7 36.0 21.1and Inlet Temp. of Water(°C.)______________________________________ The temperature gradient and Mollier diagram of this heat pump cycle are diagrammatically shown in FIG. 4a and FIG. 4b, respectively. Properties of R-12 refrigerant in the heat pump cycle presenting the Mollier diagram of FIG. 4b are given in Table 7 in comparison with the case of conventional heat pump cycle presenting the Mollier diagram of FIG. 5b. TABLE 7______________________________________ StateThis Invention A B C D E F______________________________________Temperature °C. 135.2 84.6 84.6 38.0 0.49 30.1Pressure kgf/cm2 25.6 25.6 25.6 25.6 3.2 3.2Enthalpy kcal/kg i.sub.1 i.sub.2 i.sub.3 i.sub.4 i.sub.5 i.sub.6 153.8 142.7 121.4 108.9 108.9 141.0______________________________________ StateConventional a b c d e f______________________________________Temperature °C. 135.2 84.6 84.6 79.6 0.49 30.1Pressure kgf/cm2 25.6 25.6 25.6 25.6 3.2 3.2Enthalpy kcal/kg i'.sub.1 i'.sub.2 i'.sub.3 i'.sub.4 i'.sub.5 i'.sub.6 153.8 142.7 121.4 119.9 119.9 141.0______________________________________ Notes: The symbols A to F designate the states of FIG. 4b whereas the symbols a to f designate corresponding states of FIG. 5b. From Table 7 above, the following values of performances are calculated. ______________________________________ Supercool Temperature Degree Effectiveness COP______________________________________This Invention 46.6° C. 72.6% 3.5Conventional 5° C. 7.8% 2.6______________________________________ in this way, hot water of ca. 96° C. discharged with a temperature difference of ca. 76° C. Thus far described, this invention provides a method of operating a heat pump with which it is possible to utilize effectively the supercool degree by the use of a once-through path, complete counterflow type condenser. As a consequence, a high-temperature water of 70°-100° C. or more or other high-temperature fluids can be discharged with a large temperature difference of 50°-100° C.
A method of operating a heat pump having at least one circuit for circulation of a refrigerant comprising a compressor, a once-through path, complete counterflow type condenser as a high-temperature heat output means, an expansion valve and a low-temperature heat output means (evaporator or a segregated low-stage circuit for circulation of a lower-boiling-point refrigerant), which comprises choosing a supercool degree, which is equal to the difference between a saturation temperature and an outlet temperature of the refrigerant, to satisfy the conditions that a temperature effectiveness of refrigerant liquid as defined by the formula: ##EQU1## is at least 40% and the temperature difference of the denominator is at least 35° C. As a result, boiling water of ca. 100° C. or other high-temperature fluids can be discharged with a large temperature difference.
5
BACKGROUND OF THE INVENTION The present invention relates to medical electrodes Medical electrodes are adhered to a patient's body to either collect electricity from the body at selected points or to introduce electricity into the body at selected points. Monitoring electrodes and diagnostic electrodes are examples of the former type. So-called "TENS ELECTRODES" are an example of the latter type. The present invention is useful for either type electrode, but is especially adapted for use as a tens electrode. The typical prior art tens electrode 1 (FIG. 4) includes a layer of facestock 5 adhesively coated on one surface. The facestock is of a nonconductive material and facilitates adhesion of the tens electrode to the patient's body. Adhered to the central portion of the facestock is a highly conductive dispersive layer 2, typically a tin foil layer, which is somewhat smaller in dimensions than the facestock layer. A conductive stud 3 and a conductive eyelet 4 combination function as the electrical contact for the electrode Each includes an upstanding post projecting upwardly from an outwardly radiating base. The eyelet post projects through a small aperture in the dispersive layer and in the facestock layer and into the interior of the stud post. The two are snapped together such that a portion of the dispersive layer and the facestock layer are sandwiched between the respective stud and eyelet bases. The dispersive layer and eyelet base are then covered by a moderately conductive gel layer 6. The gel layer is slightly larger in dimensions than the highly dispersive layer to insure that the dispersive layer does not make direct contact with the patient's body. The function of the highly conductive dispersive layer is to insure that an electrical charge entering through the stud and eyelet connector is dispersed outwardly and evenly across the surface of the gel layer. The gel layer then conducts the dispersed electricity generally evenly into the patient's body. The gel layer is somewhat smaller in dimensions than the facestock layer so that a portion of the adhesive surface of the facestock layer continues to remain exposed to facilitate adhesion of the entire electrode assembly to the body. As manufactured, a layer of release liner 7 is provided to cover the entire surface of the facestock and the exposed gel layer. A small "thumb tab" 8 is typically adhered to a portion of the facestock adhesive surface between that surface and the release liner to facilitate peeling the release liner away from the facestock when it is time to use the electrode. One problem with such a construction when used as a tens electrode is that hot spots tend to be created in the gel layer. There tend to be higher concentrations of electricity directly below the base of the conductive eyelet than in those portions of the gel layer located below the exposed surface of the dispersive layer. It is believed that this results from a tendency for electricity to flow more easily through the silver plated eyelet to the eyelet base than through the conductive dispersive layer. SUMMARY OF THE INVENTION In the medical electrode of the present invention, a conductive stud is combined with a nonconductive eyelet and the two are joined through the dispensive layer such that the stud base makes direct contact with the dispersive layer over a substantial portion of the stud base area, rather than with the facestock layer as is the case in conventional medical electrodes. As a result, current flowing into the contact stud flows through the stud base and directly into the dispersive layer. The dispersive layer is the only conductive member contacting the gel layer. The eyelet is nonconductive. As a result, there are no "hot spots" in the gel layer as is encountered in prior art electrodes. The use of a nonconductive eyelet member is also more economical than the use of a silver plated conductive eyelet. Consequently, the electrode of the present invention may be advantageously used as a monitoring or diagnostic electrode, even though one does not need to worry about "hot spots" in the gel layer of such electrodes. These and other objects, advantages and features of the invention will be more fully understood and appreciated by reference to the written specification and appended drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective, exploded view showing the components of an electrode made in accordance with the preferred embodiment of the present invention; FIG. 2 is a lateral cross-sectional view of the electrode of the preferred embodiment, with the layers being shown somewhat enlarged for purposes of clarity; FIG. 3 is a top plan view of the electrode of the preferred embodiment; and FIG. 4 is a lateral cross-sectional view of a prior art electrode. DESCRIPTION OF THE PREFERRED EMBODIMENT In the preferred embodiment, a conductive stud 30 is snapped together with a nonconductive eyelet 40 such that the post 42 of the eyelet projects through an aperture 21 in the dispersive layer 20 and into the receiving interior of the stud post 32 of stud 30 (FIGS. 1 and 2). The stud base 31 of conductive stud 30 makes direct contact with the surface of dispersive layer 20. A layer of facestock 50 includes an adhesive coated undersurface which adheres to the surface of conductive layer 20. An aperture 51 in facestock layer 50 is sufficiently large that it does not interfere with the direct contact between the undersurface of stud base 31 and conductive dispersive layer 20. A layer of dispersive gel 60 completely overlies the bottom surface of conductive dispersive layer 20 and the exposed nonconductive surface of eyelet base 41. A release liner 70 is adhered to exposed adhesive covered portions of facestock 50 so as to cover the entire assembly, there being a small thumb tab 80 adhered to the underside of facestock 50 near an edge thereof to facilitate subsequent peeling of release liner 70 away from the adhesive surface of facestock 50. Tin or other conductive metal foil is typically used as the conductive dispersive layer 20 in such electrodes and is applicable in the broader aspects of the present invention. However, it is preferable that the material of which conductive layer 20 is made also have sufficient tear strength that the stud 30 and eyelet 40 combination sandwiching conductive layer 20 will not tear out of conductive layer 20 when the electrode is used. To serve this more preferred aspect of the present invention, it is preferable that conductive layer 20 be made of conductive rubber. Other conductive polymeric material having sufficient tear strength could also be used. Such conductive rubber pads have also been used in prior art electrodes and are well-known to those skilled in the art. It is believed that such conductive rubber pads are made by blending a high content of powdered carbon into the rubber blend. Conductive layer 20 encompasses a sufficient area to comfortably disperse an electric current being introduced into the electrode through stud 30. In the best mode contemplated for the invention, conductive layer 20 is approximately one inch on each side. Conductive layer 20 includes a small aperture 21 in the center thereof through which the post 42 of eyelet 40 can project. Conductive stud 30 is of a conventional construction, preferably being stainless steel or nickel plated brass to enhance conductivity. It comprises a generally circular stud base 31 from which projects a central stud post 32 which is narrower in diameter than stud base 31. Eyelet 40 is nonconductive. It is preferably molded of a tough plastic material such as ABS. Such plastic eyelets are commercially available. Eyelet 40 includes a generally circular base 41 from which projects a post 42 which is narrower in diameter than base 41 and which is also slightly narrower in diameter than post 32 of stud 30. The exterior of post 42 and the interior of post 32 are dimensioned such that the two have a snug fit relative to one another when forced together. Facestock 50 comprises a layer of insulating material such as fabric or foam. In the best mode contemplated, a nonconductive, spun laced polyester fabric material is used. The preferred facestock material is "MED SPUN LACED POLYESTER"™ available from Avery International of Painesville, Ohio. The material is a porous, 2.4 ounce nonwoven material It is coated with an adhesive material, specifically a nonsensitizing acrylic adhesive. Facestock 50 is larger in dimensions than conductive layer 20 such that a substantial portion of the adhesive on the undersurface of facestock 50 remains exposed after conductive layer 20 is adhered thereto. Facestock layer 50 is, in the best mode contemplated, approximately two and one-half inches by two and one-quarter inches. Facestock 50 includes a relatively large aperture 51 in the center thereof. Aperture 51 must be sufficiently large that it does not interfere to any substantial degree with intimate electrical contact between the undersurface of base 31 of conductive stud 30 and conductive layer 20. A substantial portion of the surface area of base 31 must make direct, intimate electrical contact with conductive layer 20. To this end, it is most preferred that aperture 51 be larger in dimensions than the perimeter dimensions of base 31. This greatly facilitates the ease with which firm, intimate electrical contact can be achieved between base 31 and conductive layer 20. It also makes it possible to adhere conductive layer 20 to facestock 50 prior to securing stud 30 and eyelet 40 to conductive layer 20, and still leave base 31 in complete contact over its entire area with conductive layer 20. If such contact were to be achieved where aperture 51 were smaller in diameter than the diameter of base 31, one would have to secure stud 30 and eyelet 40 to conductive layer 20 prior to adhering facestock 50 to conductive layer 20. Gel layer 60 can be comprised of any conductive gel material. However a preferred material is known in the art as hydrogel. Hydrogel is a polymeric material which is conductive, preferably hydrophylic, has low surface resistivity and good adhesive properties. It is most preferably hypoallergenic and includes a bacteriostat and fungistat. Such materials are well-known to those skilled in the art The best mode of the present invention contemplates the use of MEMTEC™ MN500 available from LecTec Corporation of Minnetonka, Minn. Hydrogel layer 60 is adhered to and over the undersurface of base 41 of nonconductive eyelet 40 and conductive pad 20. Hydrogel layer 60 is larger in dimension than conductive pad 20 such that no portion of conductive pad 20 makes contact with the patient's skin when electrode 10 is used. Yet, hydrogel layer 60 is still smaller in dimensions than facestock 50 such that a substantial portion of the adhesive undersurface of facestock 50 is still exposed for adhesion to a patient's skin. In a best mode contemplated for the present invention, hydrogel layer 60 is approximately one and one-quarter inch by one and one-half inch. Release liner 70 is made of any conventional release liner material Examples include silicone coated kraft paper and any plastic material which does not adhere strongly to the acrylic adhesive on the undersurface of facestock 50 In the best mode contemplated for the present invention, a layer of clear polyester plastic material is used as the release liner. Such release liner material is commercially available and is well-known to those skilled in the art. Release liner 70 is coextensive in dimensions with facestock 50. To facilitate a user peeling release liner 70 away from facestock 50 to expose the adhesive undersurface thereof, a small thumb tab 80, preferably semicircular in configuration, is adhered to the undersurface of facestock 50 along one edge thereof. To use electrode 10 of the present invention, one separates facestock 50 from release liner 70 in the thumb tab 80 area thereof and subsequently peels release liner 70 away from facestock 50. The electrode is then applied to the patient at the desired location. An electrical coupling or lead is snapped over the post 32 of conductive stud 30 either before or after application of electrode 10 to the patient's body. Of course, it is understood that the foregoing is merely a preferred embodiment of the invention. Variations on the preferred embodiment would make it possible, for example, to use the invention as a monitoring or diagnostic electrode, rather than as a TENS electrode as described above. Various other changes and alterations can be made without departing from the spirit and broader aspects thereof as set forth in the appended claims, interpreted in accordance with the principles of Patent Law.
The specification discloses a medical electrode particularly well suited for use as a tens electrode wherein a conductive stud is coupled to a nonconductive eyelet, the post of which projects through an aperture in a highly conductive dispersive layer, in such a way that the stud base makes direct electrical contact with the dispersive layer. A layer of adhesive coated facestock is adhered to the upper surface of the conductive dispersive layer. The facestock includes an enlarged aperture providing clearance for the stud base. A gel layer is adhered to and overlies the undersurface of the conductive layer.
0
CROSS-REFERENCE TO RELATED APPLICATIONS This application is a National Phase Application of PCT International Application No. PCT/IL2011/000927, International Filing Date Dec. 6, 2011, entitled “SOUND MANIPULATOR”, published on Jun. 14, 2012 as International Publication Number WO 2012/077104, claiming priority of GB Patent Application No. 1020585.4, filed Dec. 6, 2010, both of which are incorporated herein by reference in their entirety. BACKGROUND 1. Technical Field The present invention relates to the field of music appliances, and more particularly, to instrument interfaces. 2. Discussion of Related Art The evolution of modern music has been greatly influenced by technological innovations that have offered musicians an ever-increasing palette of sounds and with that, the potential to make new music. As distortion and other effects led to an explosion in guitar-dominated rock genres, and as the synthesizer gave keyboard players a leading role in pop music, a new technology is about to give guitar players access to new creative horizons. Many of today's leading popular music genres, such as dance, hip hop, rap, house or techno are dominated by synthesizer and computer-generated melodies, featuring sharp, fast beats and electronic sounds that the electric guitar has difficulty blending in with. In the rock world, where the guitar is still king, new technologies are well received as players seek to expand their creative arsenals. In this application we propose a new system and method that will provide a new and exciting way to play the electric guitar. It offers guitar players to utilize a new palette of sounds, expanding their creativity, and allowing them to take a more active role in the creation of today's popular music. U.S. Pat. No. 7,541,536, which is incorporated herein by reference in its entirety, discloses a multi-sound effect system including dynamic controller for an amplified guitar. U.S. Pat. No. 7,541,536 comprises attaching a signal processing unit along with a touch-sensitive dynamic control unit upon the front panel of the guitar's body for controlling and processing electrical signals produced by an amplified guitar, e.g. electric, bass, acoustic or classical guitar. This arrangement enables the guitar player to dynamically control and manipulate in a convenient way the multi-sound effect parameters. The unit provides the guitar player with control over up to three dimensions of these parameters while simultaneously playing the guitar. The system is composed of a Signal Processing Unit (SPU), such as a Digital Signal Processor (DSP) and a Dynamic Control Unit (DCU). The DCU is a touch-sensitive dynamic control unit implemented as a sliding potentiometer, a roller potentiometer, push buttons, a tracking-ball, a touch-pad, a touch-screen, a dynamic ribbon, a joystick, a mouse, optical sensor array, infrared sensors or as a combination thereof. The SPU receives audio signals from the guitar pickups and control signals from the DCU, whereas the control signals indicate the location and pressure of the guitar player's finger over the DCU. The DCU is mounted upon the front panel of the guitar in a way that the guitar player can maneuver at least one of his free fingers (middle, ring or pinky) of his picking hand over the DCU surface in a convenient way while picking or strumming the guitar's strings. In all amplified guitars (i.e. electric, bass, acoustic or classic guitar) the DCU is attached beneath the guitar strings at the lower front area of the guitar body, whereas in a bass guitar the DCU may be further attached above the guitar strings at the upper front area of the guitar body. In the case of a bass guitar, wherein the DCU is located above the strings, the bass player can use his thumb to maneuver upon the DCU and the rest of his fingers to strike the strings. The DCU includes a sensor which measures up to three dimensions for controlling the multi-sound effect parameters simultaneously in real time, whereas in each dimension a plurality of parameters regarding the sound-effects can be changed. The plurality of parameters include common distortion parameters (such as gain, output level, tone, EQ or filter), common compressor parameters (such as Input level, threshold, gain reduction ratio, knee, attack time, release time, output level), common gate parameters (such as threshold, attack time, gain reduction ratio, range, hold or release time, decay time, output level), common modulation effect parameters (such as rate, feedback or regeneration, time delay, depth, mix), common filter effects or wah-wah parameters (such as low-pass, band-pass and high-pass filter frequency) common delay parameters (such as delay time, feedback, mix) and common reverb parameters (such as pre or initial delay, diffusion, crossover point, high and low frequency ratio, high and low frequency damping, density, balance, or early reflection delay). FIG. 1 is an overview illustration describing the different components comprising the multi-sound effect system according to the prior art. The Input Device 11 is provided for transmitting audio signals to the multi-sound effects system 10 , whereas the Output Devices 12 are provided for receiving audio signals, for receiving and transmitting control signals and for sharing data, audio and program files containing information regarding the operation and programming of the multi-sound effects system. The Input Device 11 is comprised of an electric guitar 13 , whereas the DCU 14 is attached to the lower area of the front panel. Attaching the DCU to this area of the guitar allows the guitar player to maneuver at least one of his picking hand fingers over the DCU in a convenient way while playing the guitar. Most electric guitars are completely passive, i.e. consume no power, therefore one doesn't have to plug them into a power supply. The audio signals leave the guitar through the output jack 15 , which is located on the guitar body 9 , and transmitted into the system through the Interface Unit 16 . The signal transmission is applied either by a wire cable or other wireless mechanism allowing the transmitting of the audio signals from the guitar into the system. In some cases an Intermediate Unit 31 , comprising of other instrument devices, may be applied between the guitar and the system. The intermediate unit/s can be; for example, other processing unit/s (e.g. floor-sound effects, multi-effect processors, rack-mounted processors, stomp boxes, effect pedals, equalizers, desktop effects and portable effects), a pre-amplifier, controller pedals, volume pedals, mixer, single/multi-track recorder machine, computer, other musical instruments, microphone or any combination thereof. The Output Devices 12 are composed of three different types of devices. The audio signals are transmitted to these devices via a cord cable or wireless mechanism. The first type of device 17 is comprised of an electrical instrument that reacts to the transmission of audio signals received from the system. These devices may include a guitar amp, head-phone, other multi-sound effects system, other kinds of audio signals processors (e.g. floor sound effect, multi-effect processors, rack-mounted processors, stomp boxes, effect pedals, equalizer, desktop guitar effect, portable effect), musical instrument, mixer, record machine or combination thereof. The second type of device 18 is comprised of an electrical instrument used for communicating with the system in order to receive the control signals, transmit the signals, or share data, audio and program files regarding the multi-sound effects. These devices may include a PC, a memory card, an external programming unit and other equivalent multi-sound effect systems. The third type of device 19 is comprised of an electrical musical instrument used for communicating with different musical instruments, which are supported by a Musical Instrument Digital Interface (MIDI) protocol. The protocol controls and communicates with different musical instruments and sound-effects, providing they support the MIDI protocol. The Communication Unit 20 connects between the system and Output Devices of the second type 18 , thus, providing an efficient communication. The MIDI Control Unit 21 is provided to connect to the Output Devices of the third type 19 via a cord cable or wireless mechanism. The connection between these devices is to enable control and communicate with different musical instruments and effects that are supported with MIDI protocols. The Dynamic Control Unit (DCU) 14 is implemented as a touch-sensitive sensor for controlling the SPU algorithm, which process the audio signals produced by the guitar. The DCU is provided for identifying and delivering information concerning the location or pressure of the finger activating the unit. The main advantage of this unit is that it enables the guitar player to dynamically change the various sound-effects and parameters while playing the guitar. The DCU transmits control signals either to the Management Unit 23 or directly to the SPU 22 . The Signal Processing Unit (SPU) 22 is a sound effect or multi-effect audio signal processor. This unit is designated to dynamically process and alter incoming audio signals transmitted from the guitar with respect to the control signals received from the DCU 14 , Static Control Unit (SCU) 24 or from the Management Unit 23 . The Static Control Unit (SCU) 24 is comprised of a set of buttons and knobs usually used for accessing, editing, programming and pre-setting sound-effect parameters. While playing the guitar, the SCU enables the guitar player to select and fetch effect programs from the effects bank. The SCU transmits control signals concerning the parameters to the Management Unit 23 or directly to the SPU. The Management Unit 23 is provided to handle and control the system's operation and functionality. It further manages and controls the system's peripheral devices. The Management unit receives control signals from the SCU and the DCU according to the pre-selected settings and the location of the guitar player's finger over the DCU. The unit includes a processor unit which may be in the form of a micro-processor, a Digital Signal Processing unit (DSP), a designated signal processor (e.g. FPGA, ASIC) or a processing device (e.g. ARM, RISK, Pentium, etc. . . . ). The processor unit translates the control signals into a signal format required by the SPU and processes them according to a set of commands and instructions. In addition, the Management Unit handles memory devices, display drivers, communication protocol between inner units and external devices and manages the different aspects regarding the propose system, such as initialization processes, alarms, boot, timing, programming procedures, effect editing, audio pattern recordings, etc. The Interface Unit 16 is provided to enable a physical connection between external sources, e.g. input and output devices, and the system for receiving and transmitting audio signals. The Interface Unit at the input stage transmits the analog audio signals received from the Input Device 11 to the Signal Conversion 25 and Amplification 26 Units. Whereas, at the output stage the audio signals are further transmitted to the Output Devices 17 The Signal Conversion Unit 25 includes an Analog to Digital Converter (ADC) unit and a Digital to Analog Converter (DAC). The ADC is provided to convert the analog signals received from the guitar to a digital signals format which required by the SPU. The Digital to Analog Converter (DAC) unit is provided to convert the digital signals to an analog format required by the Output Devices 17 . The Amplification Unit 26 is provided for adjusting the signal's level according to the system's and peripheral devices' requirements. The Memory Unit 27 is provided for saving and sharing the programs, data and audio files required for the proper operation of the system. The unit includes memory devices which may be in the form of ROM, RAM (such as SDRAM, SRAM.), Nonvolatile memory (such as FLASH, EPROM) or memory cards (such as smart-media, compact flash). The Memory Unit enables to read and write data to and from the SPU 22 and the Management Unit 23 . The Monitor Unit 28 and the Visual Display LEDs 29 are provided to give the guitar player relevant information of the various aspects regarding the system. The various aspects may include the operation status, alarms, operation mode (such as programming or playing modes), multi-effect banks, sound-effect parameters, etc. The Monitor Unit 28 is a complementary unit including a display device, such as an alpha-numeric display, a graphical display, a Seven-Segment display, a touch-screen display, LCD display, TFT display etc. The Visual Display LEDs unit 29 is a complementary unit comprising light bulbs, such as Light Emitting Diodes and lightened push buttons. The Keyboard 30 is a complementary unit provided for additional data entering, accessing, selecting and programming multiple sound effects. The communication is applied via an external keyboard or programming device. FIG. 2 is an illustration of the manner in which the system's inner components and DCU 14 are mounted upon the guitar according to the prior art. The system's inner components (e.g. SCU, SPU) 24 excluding the DCU are mounted upon the front panel of the guitar's body above the guitar's strings. The DCU 31 is mounted upon the front panel of the guitar beneath the guitar's strings. A strap attachment 32 is provided for attaching the components to the body of the guitar, whereas a cord wire 36 is provided for transmitting control signals between these components. The strap attachment passes under the strings of the guitar and elapses over the guitar's body. The guitar's strap buttons 33 may further be included for fastening and stabilizing the manner in which the strap attachment is applied. A cord wire 35 is provided for enabling a data transmission of the audio signals from the guitar to the system's inner components 30 and vice versa. A splitter 34 enables a dual transmission of the audio signals from the guitar to the system and from the system to the Output Devices (e.g. Guitar Amp.) via an additional cord wire 37 . The mechanism is included for attaching and detaching the DCU to the lower front panel of an amplified guitar and to the upper front panel of a bass guitar. The mechanism is at least one strap attachment, which passes under the guitar's strings in between the guitar's pickups. In the case of a lead electric guitar which contains only one pickup (as in Fender Telecaster guitars) the attachment strap passes besides and along the pickup, thus encompassing the body of the guitar and tightening the dynamic control unit to the front panel of the guitar. The attachment means is provided for connecting/disconnecting the DCU along with at least one of the other system's components as a unit to the front panel of the amplified guitar under the guitar's strings An additional method for applying the strap attachment is by threading it from side to side upon the front panel of the guitar and passing it beneath the guitar's strings in the lower area of the guitar body. The attachment encompasses the body of the guitar while tightening the DCU to the front panel of the guitar. The DCU is attached to the strap attachment using a mechanism from the group of: a pin (similar to the mechanism for combining a strap to a hand watch), a clipping device, a dedicated strap pass or slot in the unit, a velcro strap, a rubber band and a scotch tape. The mechanism may further be implemented as an attachment means from the group of a clipping device, a velcro strap, glue, vacuum buttons, a rubber band, a scotch tape and bolts. The multi-sound effect system further comprising a mechanism for attaching the system's components excluding the DCU to the amplified guitar body and to the strap attachment, wherein the mechanism is an attachment means from the group of: a strap, a clipping device, a velcro strap, glue, vacuum buttons and bolts. In accordance with further improvements of the present invention, it is suggested to provide the player with various options of effect manipulations or combination thereof: Activating, deactivating specific effect type or types; Changing the effect type or types; Activating, deactivating or changing effect patches, which is a combination of several effect types and parameters setting, in which the effect types are combined in a certain order or structure and are played together; Controlling parameters of effect algorithm which determine the activation pattern of an effect, for example, determining set of time intervals in delay effect according to the time interval between sequential fingers' tapping on a touch-pad DCU; bypassing or muting an effect; freezing the values of effect parameters according to last user action or according to predefined settings; Adjusting the effect parameters values in accordance with predetermined continues or discontinues pattern; Adjusting the effect parameters values according to a recorded continues or discontinues path of the finger's motion over the DCU or according to recorded or real time finger's tapping on the DCU. BRIEF SUMMARY Embodiments of the present invention provide a sound manipulator comprising: a touch sensitive sensor arranged to detect finger tapping that comprises finger contact upon the touch sensitive sensor (“touch”) and finger detachment from the touch sensitive sensor (“release”), and to generate a corresponding time dependant tapping signal comprising a first state corresponding to periods in which the finger contacts the touch sensitive sensor and a second state corresponding to periods in which the finger does not contact the touch sensitive sensor; and a processing unit arranged to: receive an electric audio signal associated with an instrument and control signal associated with the finger tapping upon the touch sensitive sensor; receive at least one state change characteristic; modify the time dependant signal corresponding to the finger tapping according to the at least one state change characteristic; and multiply, with a common time base, the modified time dependant signal with the electric audio signal, to yield a modified electronic signal, wherein changes of the modified electronic signal during changes between the first and the second states of the tapping signal are characterized by the at least one state change characteristic. These, additional, and/or other aspects and/or advantages of the present invention are: set forth in the detailed description which follows; possibly inferable from the detailed description; and/or learnable by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be more readily understood from the detailed description of embodiments thereof made in conjunction with the accompanying drawings of which: FIG. 1 is an overview illustration describing the different components comprising the multi-sound effect system according to the prior art; FIG. 2 is an illustration of the manner in which the system's inner components and the Dynamic Control Unit (DCU) are mounted upon the guitar according to the prior art; FIGS. 3A-3D are schematic block diagram illustrations of a sound manipulator, according to some embodiments of the invention; FIG. 4 is a schematic illustration of an electric audio signal associated with an instrument, a corresponding time dependant tapping signal, with a common time base, a modified time dependant signal, and a modified electronic signal exemplifying the operation of the sound manipulator, according to some embodiments of the invention; FIGS. 5A-5H illustrate various signal characteristics that may be adjusted by sound manipulator, according to some embodiments of the invention; FIG. 6 illustrates signal manipulation by a quantization module of the sound manipulator, according to some embodiments of the invention; FIG. 7 is a schematic flow chart illustrating a method, according to some embodiments of the invention; FIGS. 8A-8C illustrate the allocation of different areas on the touch sensitive sensor 110 to different combinations of state change characteristics, according to some embodiments of the invention; and FIGS. 9A and 9B illustrate state change characteristics relating to different channels, according to some embodiments of the invention. DETAILED DESCRIPTION Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is applicable to other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting. For a better understanding of the invention, the usages of the following terms in the present disclosure are defined in a non-limiting manner: The terms “guitar” and “amplified guitar” as used herein in this application, are defined as any type of guitar (plucked string instrument having a body and a neck and played with the fingers and/or a pick) that generates an audio signal which is electrically transmit, and thereby modified and amplified. Explicitly, the term “guitar” as used in this application includes electric and bass guitars in which the signal is generated by pickups from the vibration of the strings, amplified acoustic guitars in which the signal is generated by a microphone receiving the sound from the guitar body and depend on the acoustic characteristics of the guitar, Synthi guitars in which special pickups identify the notes played by the guitarist and generate corresponding artificial sound, digital guitars utilizing various means to receive sound related inputs from the guitarist (e.g. optical pickups) and generate related digital signals. The body of the guitar may be any of any form, including a full or hollow body (e.g. made of wood, plastic or metal). The term “guitar” as used in this application further includes body-less plucking instruments (i.e. silence guitars and alike) and may even include other string instruments, e.g. instruments played with a bow such as violin or cello. Any type of pickup may be used to receive the signal from the guitar. The term “playing the guitar” as used herein in this application, is defined as any method of generating sounds from the guitar such as plucking or picking with either the right or the left hand, or using a bow or other appliances. “Playing the guitar” further comprises fretting the strings with either the right or the left hand. The hand used to fret the guitar is defined as the fretting hand, while the other hand is defined as the picking hand. Fretting and picking may be carried simultaneously and/or alternately by one of the hands, and operating the invention may also be carried out by either or both hands. The term “electric audio signal” as used herein in this application, is defined as the electronic signal that is produced by playing the guitar. The electronic signal is processed and transformed into the guitar audio signal. The electric audio signal may include some processing of the signal received by the pick ups, and may be analog or digital. The term “sound effect” as used herein in this application, is defined as any manipulation of the basic guitar sound, and may include overdrive, distortion, fuzz, compressor, limiter, expander, gate, graphic equalizer, chorus, flanger, phaser, wah-wha, pitch shifter, harmonizer, tremolo, vibrato, uni vibe, ring modulator, talker, delay effects, reverb effects and various kinds of simulation effects, which enable the simulation of different preamps, amps, rotating speaker, guitars, cabinets, pickups and stomp-boxes. Parameters and characteristics of sound effects, as used herein in this application, may comprise for example (i) gain, tone and level for distortion, overdrive and fuzz, (ii) speed, depth, feedback/regenerator and width for modulation effects such as chorus, flanger, vibrato, tremolo, ring modulation and Lesley effect, (iii) notch, peak and resonance for filters such as wah wah, talkers, resonant filter, phaser and uni-vibe, (iv) pitch shift and additional harmonics for pitch shifter, harmonizer and detune effects, (v) time and feedback for delay effects such as echo, reverse delay and ping pong delay, (vi) environment characteristics for reverb effects, (vii) threshold, ratio, level, attack and release times, and gain for dynamic effects such as compressor, limiter, expander, as well as parameters of (viii) noise gates and other sound parameters (e.g. volume). The term “touch sensitive sensor” as used herein in this application, is defined as any device that measures touches and their characteristics, such as a touch-pad, a touch-screen, a sliding potentiometer, a roller potentiometer, push buttons, a tracking-ball, a dynamic ribbon, a joystick, a mouse, optical sensor array, infrared sensors or a combination thereof. The touch sensitive sensor may be any kind of a surface that may be used to identify a finger touch upon the surface, either as an integrated touch pad or as a combination of a surface and sensor(s), including touch sensitive sensors that are operational on other devices such as communication devices and data processing devices. The touch sensitive sensor may measure location and pressure the touches, as well as multiple touches. The touch sensitive sensor may comprise any type of touch pad, as well as a multi touch trackpad, and may further be somewhat flexible to enhance a touching feel. One of the reason different instruments sound differently is the way they produce sound. Similar notes played by different instruments have a similar basic frequency yet differ in their timbre due to various sound parameters such as the composition of harmonies in the sound, spectrum width and ADSR parameters such as the sound envelope. A sound may be defined in respect to time and frequency and be characterized by relative amplitudes of each of the included frequencies over time. The attack and decay of the sound influence the instrument's character. Sound production is characterized by the ADSR (Attack Decay Sustain Release) envelope that defines the way sound is produced. Attack time is the time taken for initial run-up of level from nil to peak. Decay time is the time taken for the subsequent run down from the attack level to the designated sustain level. Sustain level is the amplitude of the sound during the main sequence of its duration. Release time is the time taken for the sound to decay from the sustain level to zero after the key is released. Embodiments of the current invention comprise a system and method of changing any of the sound characteristics (e.g. ADSR and ASDSR sound envelopes, frequency range and intensity) of the guitar sound using a touch sensitive sensor. The system allow the player to generate sound by touching or tapping touch sensitive sensor 110 without picking the strings. Sound may then be taken from the guitar according to the positions of the fretting hands. String vibrations may be generated (at least before using touch sensitive sensor 110 ) by either an initial strum, or using the fretting hand (e.g. by hammer on and by pulling the strings). FIGS. 3A-3D are schematic block diagram illustrations of a sound manipulator, according to some embodiments of the invention. Sound manipulator 100 comprises a touch sensitive sensor 110 connected to a processing unit 120 . Processing unit 120 is arranged to receive electric audio signal 200 associated with instrument 90 that is played simultaneously during the finger tapping. Instrument 90 may comprise an amplified guitar of any kind, a synthi guitar, or any other stringed or non-stringed instrument. Electric audio signal 200 may be associated with an electronic instrument producing a synthesized signal 200 . In particular, embodiments of the invention comprise an amplified guitar comprising sound manipulator 100 embedded therein, built into the guitar body or attach thereupon, with electric audio signal 200 being a signal from the guitar pickups, that may be further modified by various electronical means and comprise sound effects. FIG. 4 is a schematic illustration of an electric audio signal 200 associated with an instrument 90 , a corresponding time dependant tapping signal 210 , with a common time base, a modified time dependant signal 220 , and a modified electronic signal 230 exemplifying the operation of sound manipulator 100 , according to some embodiments of the invention. Touch sensitive sensor 110 may be responsive to the location, pressure and tapping speed and intensity of the finger(s) applied to it. Touch sensitive sensor 110 is arranged to detect finger tapping that comprises finger contact upon touch sensitive sensor 110 (“touch”) and finger detachment from touch sensitive sensor 110 (“release”). Adding touch sensitivity sensor like touch pad to the guitar provide the guitar player with a new way to play guitar. The touch pad can be used as a Sound-Gate which means that no sound will be produce unless the pad is in touch. In this case, the guitar player will play the guitar chord or solo notes with his fretting hand in a standard manner, but he will use his picking hand to rhythmically tap the pad to produce some kind of sharply slices sound with a finger tapping beat. This gives the guitar player an opportunity to produce slice sounds in a similar manner to the sounds produced by keyboard players where they are pressing releasing rhythmically chord or notes using a synthesizer keyboard. Furthermore, the touch pad can be used booth as a Sound-Gate and effect controller allowing different sound to be produce only and according to the finger contact point on the pad. As for example, the pad X axis can be assigned to control the amount of pitch shifting (say from 0 to one octave above) and the pad Y axis can be assigned to control the wahwah filter range (say from 50 Hz to 2500 Hz). By playing guitar chord or notes with his fretting hand while simultaneously tapping the pad in different X-Y locations with his picking hand the guitar player can sharply manipulate the guitar sound characteristic providing a variety range of slice sounds, which allows using the guitar in new types of music in which the guitar is currently not used, such as pop, dance and trance music. Each axis may be associated with several parameters, e.g. X axis with wah wah and gain, Y axis with pitch and tremolo speed. Controlling the sound in this manner also allows developing new directions in rock music and new guitar playing styles. The Sound-Gate can be program to operate that no sound will be produce only when the pad is in touch, this gives the guitar player the abilities to play the guitar in regular manner while combining part of rhythmically muting sound possibilities whenever he tap the pad. Another feature of the Sound-Gate that it can be programmed to record slicer patterns and play them according to the guitar player commands. Using touch sensitive sensor 110 may be simultaneous or sequential to plucking the strings. Touch sensitive sensor 110 may be used to initiate the sound from plucked strings, replace plucking, or define time periods in which the sound is produced, muted, or manipulated in different ways (e.g. different sound effects are added). For example, touch sensitive sensor 110 may be used to define a temporal pattern, processing unit may define buffer sizes that correspond to the temporal pattern, and while playing, the sound may be fitted into the buffer size pattern repeatedly by starting over the buffer size pattern at the end of each buffer size pattern. The characteristics of touching touch sensitive sensor 110 may be associated with specific ADSR parameters, for example such that emulate keyboard sound or percussion sound on the basis of the played guitar sound. Several touch sensitive sensors 110 may be positioned at various location on instrument 90 , e.g. on the body and on the neck of a guitar, or above and below the string. Different touch sensitive sensors 110 may be associated with different functionalities, according to the preferences of the player. Two touch sensitive sensors 110 may be tapped with different fingers, for example a lower touchpad may be tapped with the pinky finger and an upper touchpad with the thumb, such that a rhythmic movement with the wrist allows tapping both pads. In another embodiment, two touch sensitive sensors 110 may have different functions—e.g. the one may control turning sound effects on and off, while the other may control sound effect parameters. Any touch sensitive sensors 110 may be arranged to allow multi touch inputs relating to various parameters. Touch sensitive sensor 110 may be arranged to detect simultaneous touches by several fingers, and special effects or parameters may be associated therewith. E.g. a certain sound effect may be operated or activated upon detection of two fingers touching touch sensitive sensor 110 , while movement of one finger on the pad may change their parameters. In another example, location of touching touch sensitive sensor 110 may correspond to a designated string in a system of string designated pickups. Touch sensitive sensor 110 may be used to designated specified effects to each string separately. Touch sensitive sensor 110 is arranged to generate a corresponding time dependant tapping signal 210 comprising a first state 212 corresponding to periods in which the finger contacts touch sensitive sensor 110 and a second state 214 corresponding to periods in which the finger does not contact touch sensitive sensor 110 . First state 212 may either be higher or lower than second state 214 . Any of states 212 , 214 may represent essentially unaltered electric audio signal. Any of states 212 , 214 may correspond to a partly or fully muted electric audio signal. Each one of states 212 , 214 may correspond to a different modification of electric audio signal 200 . For example, touching touch sensitive sensor 110 may allow sound pass through the system (“muter on release”), while during periods touch sensitive sensor 110 is not touched sound may be muted. In this example, tapping touch sensitive sensor 110 may replace picking the strings by the pick. This method may imitate keyboard sound production. Moreover, the system produces sound associated with all strings simultaneously, while picking produces sound from the string sequentially. Compressing or distorting the sound before applying touch sensitive sensor 110 functionality creates sustain than enhance the effect, and make it more easy to produce sound by pressing on the string with the fretting hand. Touch sensitive sensor 110 may be used to directly produce sound according to fretted notes, instead of picking the strings. Touch sensitive sensor 110 may allow playing with additional fingers which picking the strings. Touch sensitive sensor 110 may be used to either or both generate sound and manipulate picked sound. In another example, touching touch sensitive sensor 110 mutes the guitar sound, generating abrupt discontinuations of the sound (“muter on touch”). In this technique, combining regular playing and tapping generates continuous changes between these two sound types. Touch sensitive sensor 110 may be further arranged to detect finger positions upon touch sensitive sensor 110 and generate the corresponding time dependant tapping signal 210 in relation to the detected finger positions according to specified rules, to yield differing time dependant tapping signals 210 for different finger positions. “Muter on release” may be combined with sound effect parameter determination by the X and Y location of the hand touching touch sensitive sensor 110 . Various areas on touch sensitive sensor 110 may be defined to produce sound with different pitch in respect to the original sound, e.g. an octave above or below a fretted note. intermediate areas between two defined areas may generate sound of intermediate characters, e.g. a left region on touch sensitive sensor 110 may generate the original pitch, a right area on touch sensitive sensor 110 may generate the sound an octave higher, and touching the middle area of touch sensitive sensor 110 generates an intermediate sound, according to its distances from the left and the right regions of touch sensitive sensor 110 . Alternatively, only predefined pitch changes may be allowed. The Y axis may be used to add effects upon these pitch changes, e.g. a wahwah effect with a filter position depending on the vertical position of the finger. Touch sensitive sensor 110 may be further arranged to detect finger pressure on touch sensitive sensor 110 , and processing unit 120 may be arranged to adapt the received at least one state change characteristic according to the detected finger pressure and tapping intensity. Tapping intensity (or “velocity”) in a “muter on release” mode may be used to determine the volume of the produced sound. Sound effect parameters may also be determined by the tapping intensity, e.g. distortion gain. In combination, touch sensitive sensor 110 in a “muter on release” mode may change pitch and distortion gain according to touch location on the X axis, change the size of reverb space and the opening of the resonance filter according to touch location on the Y axis, and change overall volume according to tapping intensity. This combination generates unique guitar sound when tapping the pad. Various sound effects 91 , 92 , 93 , 94 , 96 may be applied to the basic sound, and various parameters of the sound effects may be changed using touch sensitive sensor 110 . For example, in order to enable a continued rhythmical pattern, the signal from the guitar pickups may be compressed or sustained. The sustainment of electric audio signal 200 may be used to generate a percussion-like effect on fretted notes, thereby allowing the player to pick and/or tap the fretted notes simultaneously. Some sound effects 91 such as compression and sustain, may be added to electric audio signal 200 before multiplying modified time dependant signal 220 thereupon, in order to enhance the effects of the multiplying. Other sound effects 92 may be applied to modified electronic signal 230 . Moreover, some sound effects 93 , 94 , 96 may be applied to electric audio signal 200 only in association with taps on touch sensitive sensor 110 . Touch sensitive sensor 110 may be positioned on the amplified guitar, and modified electronic signal 230 may comprise modifications that comprise at least a partial muting of electric audio signal 200 ; at least a partial muting of sound effects incorporated in electric audio signal 200 ; and changes of sound effect characteristics. The modifications may be determined by a player of the amplified guitar both by defining the at least one state change characteristic and by a connection position of touch sensitive sensor 110 within an assembly of sound effects connected to the amplified guitar. The position of touch sensitive sensor 110 among the assembly of sound effects may determine the sound effects on which the modifications (by tapping) are applicable, and the sound effects that are added upon modified electronic signal 230 . Processing unit 120 is further arranged to receive at least one state change characteristic, which may comprise any of the following: an association of “touch” and “release” with the first and the second states; an attenuation state associated with at least one of the states; and types of transitions in the modified electronic signal upon changes of the tapping signal between states. The association of “touch” and “release” with first and second states 212 , 214 may be that a “touch” determines first state 212 or second state 214 and that a “release” determines second state 214 or first state 212 respectively. Differing associations may correspond to differing finger positions on touch sensitive sensor 110 . FIGS. 5A-5H illustrate various signal characteristics that may be adjusted by sound manipulator, according to some embodiments of the invention. State change may be abrupt or gradual, in correspondence with touch and release characteristics ( FIG. 5A ), or differing from touch characteristic in specified ways ( FIG. 5B ). Attack and decay of taps in modified time dependant signal 220 may be defined by various curves ( FIG. 5C ) thereby defining the ADSR envelope of the sound that is passed through by signal multiplication and results in modified electronic signal 230 . The exact form of modified time dependant signal 220 may comprise an attack curve, a decay curve that are user determined. Curve types may be either inputted by touch sensitive sensor 110 or selected from predefined options. Durations of application of each curve may be determined by a duration of touch on touch sensitive sensor 110 . Touch sensitive sensor 110 may be arranged to determine sound effect parameters by either location of the touch, pressure applied on touch sensitive sensor 110 , duration of the touch, or intensity of tapping (also termed “velocity”, FIG. 5 D)—the temporal derivative of the pressure applied on touch sensitive sensor 110 . Various parameters may be determined by characteristics and combinations of the above. E.g. a brief tap may designate a low gain, a longer tap may designate a high gain. Moving a finger over touch sensitive sensor 110 may be used to characterize smoothly varying parameters (e.g. pitch or wah's). Slow tapping may define a longer reverb while abrupt tapping may designate reverb dismissal. Tapping intensity may determine sound effect parameters such as filter width, or even the pitch. Filter width or filter shifts may be determined by the intensity of tap. An intense tap may generate a note at a specified interval from the basic tone, and a weak tap may not generate such a note or generate a note at a specified smaller interval. The location of the tap may also determine such sound effect parameters, such that x position, y position, intensity and duration of each tap may define different sound effect parameters and sound effect combinations ( FIG. 3C ). Expression pads may also be controlled by touch sensitive sensor 110 , in a similar manner to sound effects. Either touch sensitive sensor 110 or processing unit 120 may assign different state amplitudes to the taps ( FIG. 5E ). At touch sensitive sensor 110 , state amplitudes may correlate with the intensity of each tap. At processing unit 120 , state amplitudes may be pre-programmed. Taps (of tapping signal 210 ), which represent state changes (either between touch and release or between release and touch, or both, with different parameters) may be selected to have various specified forms (dictating various corresponding ADSR envelopes for the sound 210 of instrument 90 , resulting in modified sound 230 ) as presented in FIG. 5 F—various extents and forms of the ADSR envelope, FIG. 5 G—various forms, attack and decay forms of the ADSR envelope, and FIG. 5 H—multiple recurring ADSR envelopes in each tap. State change characteristics may comprise an attenuation state associated with either first or second state 212 , 214 . For example, electric audio signal 200 may be fully muted (either upon touch or upon release), or attenuated to a specified state (e.g. to 40% upon touch or upon release). Parts of electric audio signal 200 may also be attenuated, such as specific sound effects. One of first or second state 212 , 214 may correspond to by passing the sound effects on producing the basic sound of instrument 90 (when electric audio signal 200 comprises a basic signal and mixed sound effects). The modification of the mixed sound effects may comprise initiating the effect; changing a parameter of the effect; changing an intensity of the effect; and terminating the effect. The modification of the basic signal may comprise initiating the basic signal; changing a volume of the basic signal; changing a pitch of the basic signal; and terminating the basic signal. Differing finger positions on touch sensitive sensor 110 may correspond to different attenuation states or to different parts of electric audio signal 200 (e.g. specific sound effects or specific characteristics of the basic sound) such that tapping at different positions on touch sensitive sensor 110 yields different types of modifications of modified electronic signal 230 . State change characteristics may comprise types of transitions in modified electronic signal 230 upon changes of tapping signal 210 between states 212 , 214 . In particular, transitions corresponding to state changes may be designed to avoid a ticking sound upon switching between states 212 , 214 (on touch or on release). Various gradual transitions may be forced upon either tapping signal 210 or modified electronic signal 230 , and these may be selected either at processing unit 120 or by touch specific positions on touch sensitive sensor 110 . Touch sensitive sensor 110 may further be arranged to detect finger movement upon touch sensitive sensor 110 , and processing unit 120 arranged to adapt the modification according to the detected finger movement. Processing unit 120 may be further arranged to modify time dependant signal 210 corresponding to the finger tapping according to the state change characteristics. Alternatively, processing unit 120 may be arranged to modify modified electronic signal 230 according to the state change characteristics. Processing unit 120 is further arranged to multiply, with a common time base, modified time dependant signal 220 with electric audio signal 200 , to yield modified electronic signal 230 , wherein changes of modified electronic signal 230 during changes between first and second states 212 , 214 of tapping signal 210 are characterized by the state change characteristics. As an example, modified electronic signal 230 may substantially equal electric audio signal 200 during substantially the duration of first or second state 212 , 214 , and substantially equal a low volume version of electric audio signal 200 , characterized by the state change characteristics during substantially the duration of second or first state 214 , 212 respectively. Electric audio signal 200 may comprise a basic signal and at least one mixed sound effect, which may be independently modified by tapping. For example, processing unit 120 may multiply, with a common time base, modified time dependant signal 220 with either the basic signal and/or the sound effect to yield modified electronic signal 230 . The multiplying of modified time dependant signal 220 with electric audio signal 200 may comprise differing specified sound effect compositions for first and second states 212 , 214 . Sound manipulator 100 may operate for example according to the touch and release periods and characteristics as described above. In embodiments, various aspects of the touch profile may be pre-programmed (either via touch sensitive sensor 110 or independently) such as to be activated by actual touch in a specified way. For example, touch duration and intensity may be pre-programmed. Sequences of pre-programmed touch profiles may be associated with each touch. Sound manipulator 100 may additionally comprise a module arranged to fit a tapping pattern onto a specified temporal grid. FIG. 6 illustrates signal manipulation by a quantization module 160 of sound manipulator 100 , according to some embodiments of the invention. As shown in FIG. 3D , sound manipulator 100 may comprise a quantization module 160 arranged to fit time dependant tapping signal 210 onto a specified temporal grid, such as to allow synchronization of modified electronic signal 230 with other electronic signals having their temporal grids. Quantization module 160 may allow the player to program a pattern and define a tempo (e.g. number of bit per minute) and to fit the programmed pattern to defined tempo. The fitting may be adjusted manually. States 212 , 214 may correspond to buffer sizes which may be determined by tapping and adjusted to a time grid. These buffer sizes may then be used to manipulate played sound according to the state change characteristics. A given pattern of buffer sizes may be used to manipulate played sound according to the state change characteristics repetitively, according to player commands inputted on touch sensitive sensor 110 . The buffer sizes may be used to synchronize real time playing or recorded sound with other instruments or with other recorded sound, as well as to synchronize real time playing with a given beat. The sequence of buffer sizes may be started over continuously to generate a long pattern of recurring buffer size distribution loops to be used to change a continuously incoming signal. The tempo may be defined according to the tapping tempo, according to an inputted beat rate (manually or electronically per communication), or by analyzing the tempo of the incoming electric audio signal or of a pre-recorded track. The fitted pattern may be operated manually by touching touch sensitive sensor 110 , as a single or recurrent pattern, or may be stopped manually by touching touch sensitive sensor 110 . Quantization module 160 thus allows incorporating patterns that were previously recorded (with touch sensitive sensor 110 , and with fitting to a specified tempo) within a current playing session. In the example presented in FIG. 6 , signal 95 represent an actual tapping to the player. Signal 95 is generates by touch sensitive sensor 110 time dependant tapping signal 210 , which may be modified to modified time dependant signal 220 by changing tap signal form ( 220 A), tap signal duration ( 220 B) or intensity, and also the timing ( 220 C) by attaching the tapped signal to a specified temporal grid 225 that allows synchronizing the tapping with other instruments, and generate tapping patterns that may be played and adjusted in later playing. Quantization module 160 may be used to synchronize instrument 90 with other instruments, e.g. during studio recordings or during live play, by either electronically processing the temporal grids to fit, or by manually (e.g. live) adjustment of the specified temporal grid (e.g. of a recorded tapping pattern) by the player using touch sensitive sensor 110 itself to fine tune the temporal grid. As shown in FIG. 3D , sound manipulator 100 may further comprise a recorder 150 arranged to record time dependant tapping signal 210 . Processing unit 120 may be arranged to generate modified electronic signal 230 from the recorded played time dependant tapping signal and the simultaneous electric audio signal 200 upon a specified finger tap detected by touch sensitive sensor 110 . Processing unit 120 may apply the modifications relating to the recorded signal repeatedly, such as to generate a repeating pattern of recurring modifications, in association with electric audio signal 200 for which they were recorded or in association with freshly produced electric audio signals 200 . Recorder 150 may be controlled by touching touch sensitive sensor 110 . Sound manipulator 100 may comprise a communication module 170 arranged to allow to: transmit the signals from touch sensitive sensor 110 to processing unit 120 and/or transmit electric audio signal 200 to processing unit 120 and/or transmit modified electronic signal 230 from processing unit 120 to a control unit 180 which may manage touch sensitive sensor 110 , various characteristics of its operation and sound effects. Multiple ADSR envelope manipulators 100 may be connected in any configuration in respect to various effects (examples are: sustain; compression; overdrive; delay; reverb; wah-wah; techno-wah; chorus; tremolo; talkers; and flanger) to allow modification of any of them according to the order of connection. Sound manipulator 100 may be connected to control unit 140 and the parameters of the modifications may be control either via control unit 140 or via touch sensitive sensor 110 in communication therewith. Touch sensitive sensor 110 may attachable or connected to an amplified guitar, such that processing unit 120 receives the electric audio signal generated by the amplified guitar. The connection of touch sensitive sensor 110 to the amplified guitar may be permanent, or touch sensitive sensor 110 may be attached to and detached from the amplified guitar at varying positions and times. Touch sensitive sensor 110 may be attached to the amplified guitar such as to allow positioning fingers of either the picking hand, the fretting hand or both onto touch sensitive sensor 110 . For example, touch sensitive sensor 110 may be positioned in the vicinity of the picking hand to allow simultaneous picking the strings and tapping touch sensitive sensor 110 , or touch sensitive sensor 110 may be positioned in the vicinity of the fretting hand to allow simultaneous fretting the strings and tapping touch sensitive sensor 110 . Sound manipulator 100 may be integral in the amplified guitar. Using sound manipulator 100 with the amplified guitar allows producing new types of sound from the electric. In particular, keyboard-like attack and abrupt discontinuation of notes is enabled for the first time. Furthermore, the keyboard-like attack and abrupt discontinuation may be applied to sound ingredients and to associated effects, singly or commonly. A gradual modification is further applicable via sound manipulator 100 , e.g., by moving the finger to control a duration of the modification or its intensity. Sound manipulator 100 may be used in association with various sound sources, starting from various guitar types, through other stringed instrument, and reaching synthesized sound that may as well be manipulated by sound manipulator 100 . FIG. 7 is a schematic flow chart illustrating a method 300 , according to some embodiments of the invention. Method 300 comprises the following stages: generating ( 310 ), from detected finger tapping on a surface, a corresponding time dependant tapping signal comprising a first state corresponding to periods in which the finger contacts the surface and a second state corresponding to periods in which the finger does not contact the surface; and multiplying ( 320 ), with a common time base, the time dependant signal upon an electric audio signal associated with an instrument that is played during the finger tapping, to yield a modified electronic signal. Changes of the modified electronic signal during changes between the first and the second states of the tapping signal are characterized by at least one specified state change characteristic. Method 300 may further comprise defining ( 330 ) the at least one specified state change characteristic comprises at least one of: an association of finger contact with the surface and finger detachment from the surface with the first and the second states; an attenuation state associated with at least one of the states; and types of transitions in the modified electronic signal upon changes of the tapping signal between states. The modified electronic signal may comprise modifications that comprise at least one of: at least a partial muting of the electric audio signal; at least a partial muting of sound effects incorporated in the electric audio signal; and changes of sound effect characteristics. Method 300 may further comprise generating ( 340 ) a guitar sound by fretting the strings and simultaneously tapping with at least one finger upon the surface to modify the simultaneous guitar produced electronic signal. Method 300 may further comprise recording ( 350 ) a pattern of finger actions and applying the modifications relating to the pattern repeatedly. A simple method to measure the frequency response is to use sine wave input and sweep the frequency over the audio spectrum 0-20 KHz. The power of the output represented in DB at each frequency point of the DUT (Device Under Test) is directly proportional to the frequency response. Touch sensitive sensor 110 may be used to determine and manipulate a frequency response of modified electronic signal 230 . Touch sensitive sensor 110 may be used to determine various frequency filters to manipulate the frequency response. For example, touch sensitive sensor 110 may emulate a graphic equalizer controlled by selecting filter levels as X,Y locations. Single filters (width and height) may be selected and controlled by touch sensitive sensor 110 . Touch sensitive sensor 110 may interpret a curve marked by a touch as a frequency response curve. This embodiment allows the player to easily determine a continuous frequency response. The continuous frequency response may be processed to produce an filter setting that is equivalent to the inputted frequency response curve. Touch sensitive sensor 110 may be used to manipulate the harmonies that constitute electric audio signal 200 singly or groupwise, and add or remove various harmonies above or below the dominating pitch. For example, X axis regions on sensitive sensor 110 may be associated to specified harmonies in the sound and Y axis values may be used to define the amplitude of the respective harmony. In this way, touch sensitive sensor 110 allow controlling sound composition during playing the instrument. The state change characteristic may comprise differing characteristics associated with differing finger positions on touch sensitive sensor 110 , such that tapping at different positions on touch sensitive sensor 110 yield different types of modifications of modified electronic signal 230 . FIGS. 8A-8C illustrate the allocation of different areas on touch sensitive sensor 110 to different processing types, e.g. different effect combinations, different band filters of frequency bands and other combinations of state change characteristics. For example, different defined areas 113 on touch sensitive sensor 110 may relate to specific sound characteristics such as effect combinations ( FIG. 8A ). Another example is the emulation of a graphic equalizer, in which, different defined areas, such as columns 114 ( FIG. 8B ), on touch sensitive sensor 110 may correspond to different band filters, and the location of the finger is used to indicate the relative intensity of each filter. The differing characteristics comprise band filters of specified frequencies and widths. Touch sensitive sensor 110 may comprise a touchpad having an interface surface, on which different areas 113 are defined to relate to at least one of: a combination of state change characteristics, characteristics of a band pass filter applied to the electric audio signal, and characteristics of harmonies added to the electric audio signal. Processing unit 120 may be further arranged to change a frequency response associated with electric audio signal 200 according to a curve 115 delineated by a finger on touch sensitive sensor 110 ( FIG. 8C ). Another example for the state change characteristics a pitch of electric audio signal 200 . The sound manipulator may e.g. add a transposition of electric audio signal 200 into a higher or lower specified pitch in addition to electric audio signal 200 , and the added sound may be controlled by finger movements on touch sensitive sensor 110 . A graphic equalizer comprises a bank of sliders for boosting and cutting different bands (or frequency ranges) of sound. Each band is controlled by a band filter. The area of touch sensitive sensor 110 may be separated to stripes corresponding to these bands. Finger touch may determine range and intensity of each filter. Touch sensitive sensor 110 may be arranged to allow a user indicate a continuous line thereupon, and adjust filters to achieve the indicated frequency response. The state change characteristic may comprise relative intensities of harmonies in electric audio signal 200 and to add sounds and harmonies thereto. For example, tapping of finger positions may be used to determine relative intensities of the harmonies from which electric audio signal 200 is composed, such as to allow the player change the character and timbre of the instrument during playing. The amplitudes of each harmonic component in electric audio signal 200 may be increased or decreased by corresponding touches on touch sensitive sensor 110 , either in a preprogrammed way (e.g. adding a tone above the played tone, adding an octave harmony, adding a low harmony of half the frequency of the played tone). Areas 113 may be allocated to specific harmonic additions or substitutions (preprogrammed or defined while playing), e.g. different areas 113 for an addition of a sub-octave, an octave, two octaves etc. Columns 114 may be allocated to specific harmonic additions or substitutions and the position of the finger within column 114 may be used to determine the intensity of the corresponding sound component, e.g. a harmony or an added tone. FIGS. 9A and 9B illustrate state change characteristics relating to different channels, according to some embodiments of the invention. State change characteristics may comprise a change in balance between different channels, such as to interpret the two dimensional signal inputted through the touch sensitive sensor 110 as a spatial design of the sound. For example, finger moves may influence stereo or surround sound parameters such as balance or perceived motion of the sound. State change characteristics may comprise a relative intensity of different channels or an association of sound effects with sound channels. As illustrated in FIG. 9A , effects 91 , 92 and 93 may be associates with different outputs 401 such as left and right channels, and be switched between the outputs upon state changes, with corresponding state change characteristics. The position of the finger may determine the relative power of different output channels, for example touching the left part of the touchpad may produce sound from the left speaker only, and moving the finger to the right end of touch sensitive sensor 110 may produce sound from the right speaker only. For example, the position of the finger relative to the borders of touch sensitive sensor 110 may be linearly interpreted as the balance between the left and right channels (e.g. on touch sensitive sensor 110 having 1024 pixels, a location of 800 pixels to the left translates to ca. 78% of the signal in the left channel, and the rest 22% in the right channel. In case of a surround sound system, the speakers may be arbitrarily mapped upon touch sensitive sensor 110 and the relative position of the finger determines the relative volume of the speakers. For example, in a 2000×2000 pixel touch sensitive sensor 110 , four speakers may be mapped in the corners and a central speaker in the center of sensor 110 (1000, 1000) or in the center of one of its sides (0, 1000) as illustrated in FIG. 9B . Single effects may also be moved from channel to channel, corresponding with finger movements on touch sensitive sensor 110 . For example a distortion effect may be applied only to one channel or only to one output 401 . FIG. 9B further illustrates a case of the two states 410 , 420 occurring at different positions on touch sensitive sensor 110 . In some embodiments of the invention, “touch” 410 and “release” 420 may occur on different positions and the distance 415 , e.g. a finger slide, may be used to encode a further state change, a state change characteristic or a combination thereof, such as for example a change in the balance between outputs 401 , or any combination of effects and their parameters. The magnitude and direction of distance 415 may be used either separately or in combination to encode the respective feature. Distance 415 between the finger contact upon the touch sensitive sensor (“touch” 410 ) and the finger detachment from the touch sensitive sensor (“release” 420 ) may be used to change a state change (e.g. switch touch and release), a state change characteristic (e.g. widen or narrow the state change, change effects switched between states, or otherwise influence the modification of the tapping signal), the tapping signal (e.g. modify the signal itself in any manner), an association of a state characteristic with a plurality of outputs (e.g. move single effects between outputs 401 as illustrated in FIG. 9A ), and a balance between different outputs (a straightforward change of balance a surround system as illustrated with outputs 401 being mapped speakers as explained above). In the above description, an embodiment is an example or implementation of the invention. The various appearances of “one embodiment”, “an embodiment” or “some embodiments” do not necessarily all refer to the same embodiments. Although various features of the invention may be described in the context of a single embodiment, the features may also be provided separately or in any suitable combination. Conversely, although the invention may be described herein in the context of separate embodiments for clarity, the invention may also be implemented in a single embodiment. Furthermore, it is to be understood that the invention can be carried out or practiced in various ways and that the invention can be implemented in embodiments other than the ones outlined in the description above. The invention is not limited to those diagrams or to the corresponding descriptions. For example, flow need not move through each illustrated box or state, or in exactly the same order as illustrated and described. Meanings of technical and scientific terms used herein are to be commonly understood as by one of ordinary skill in the art to which the invention belongs, unless otherwise defined. While the invention has been described with respect to a limited number of embodiments, these should not be construed as limitations on the scope of the invention, but rather as exemplifications of some of the preferred embodiments. Other possible variations, modifications, and applications are also within the scope of the invention. Accordingly, the scope of the invention should not be limited by what has thus far been described, but by the appended claims and their legal equivalents.
A sound manipulator comprising a touch sensitive sensor detecting finger tapings and multiplying them electronically on simultaneously produced sound, such that touches and releases affect sound composition in part (e.g. added sound effects and their characteristics) or as a whole (e.g. full or partial muting). The Sound manipulator may be attached to a guitar and allow the player both pick and tap fretted tones to give a fully new type of sound producing to the guitar. Rhythmical and electronic music may be imitated by the Sound manipulator, without losing the basic authentic guitar sound and while maintaining the flavor of live play.
6
RIGHTS OF THE GOVERNMENT The invention described herein may be manufactured, used, and licensed by or for the United States Government for governmental purposes without the payment to me of any royalty thereon. FIELD OF THE INVENTION The present invention relates to security devices and more particularly to a security device for detecting tampering of a closed object or movement of a secured object. Disturbance of individual fibers in a fiber optic bundle is utilized to detect tampering. BRIEF DESCRIPTION OF THE PRIOR ART Many different types of ties have been long used for sealing enclosures and locked objects. Often a wire loop and metal seal are employed. If the enclosure is tampered with, the seal is torn or otherwise defaced to indicate tampering. Although such mechanical means are often satisfactory, it is a relatively simple matter to replace the seal with an identical seal so that tampering may go undetected. The prior art has recognized that fiber optics may be employed as a seal which inherently detects tampering. U.S. Pat. No. 3,854,792 is directed to a fiber optic bundle which is passed through clamps on an object to be secured. One end of the fiber optic bundle is masked and illuminated so as to produce a particular output light pattern at the other end of the bundle. This output light pattern is recorded and the seal may be checked again and again by illuminating the masked end, and checking the light pattern at the other end for similarity with the initial recorded pattern. In addition to the disadvantage of having to install a mask, this patent requires the separated bundle ends to be epoxied in fiber securing or fixing anchors, at each end of the bundle. As a result, it will be appreciated that the prior patented security seal is inconvenient and time consuming to use. In a co-pending application, Ser. No. 759,161, filed Jan. 13, 1977, an improvement of the described prior art was disclosed. In the co-pending application, there is disclosed a collar for collecting the output ends of a fiber optic bundle loop. The collar employs a flexible ferrule for compressing the outward ends of the loop together to form an arbitrary pattern of intermingled fibers. When light is passed through the fiber optics, the individual intermixed fibers generate a unique "fingerprint" or pattern which may be viewed at the collar. The invention disclosed in the co-pending application utilizes an appropriate compressible ferrule which retains the individual fibers together yet does not exert sufficient shearing force to destroy individual fibers. BRIEF DESCRIPTION OF THE PRESENT INVENTION The present invention is an improvement of the fiber optic device disclosed in the co-pending application. Although the co-pending device operates satisfactorily, it requires assembly in the field. It has been determined that it would be much more advantageous if a preassembled device were available. The present invention satisfies such a requirement by including a snap-together connector which maintains opposite ends of the fiber optic bundle. Thus, in order to use the present invention in the field, it need only require snap-together connection. The snap-together connector is made tamper-resistant by surrounding it with an intermediate length of the fiber optic bundle in such a fashion that fibers must be severed in order to gain access to the locking mechanism. BRIEF DESCRIPTION OF THE FIGURES The above-mentioned objects and advantages of the present invention will be more clearly understood when considered in conjunction with the accompanying drawings, in which: FIG. 1 is a perspective view illustrating the fiber optic device of the prior art. FIG. 2a is a simplified view of illustrating the basic concept of the present invention. FIG. 2b is a view detailing one aspect of the concept of FIG. 2a. FIG. 3 is a cross-sectional view of a first embodiment of the present invention. FIG. 4 is a cross-sectional view of a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION Referring to the figures, and more particularly FIG. 1 thereof, a prior art fiber optic seal, as disclosed in the mentioned co-pending application is shown. The fiber optic bundle 1 of many small randomly oriented fibers forms the heart of the fiber optic seal. The fiber optic bundle is passed through the apertured flanges 2 provided for sealing the container or item 3 to be secured. The two ends of the bundle are looped together with the fibers intermixed and fed into a common collar 4. When light is directed on a portion of the randomly distributed intermixed fibers that pass through the collar, a unique pattern or "fingerprint" is formed at the collar end. This unique fingerprint is utilized to ensure that the seal is tamper-resistant/tamper-indicating. Since the seal is looped upon itself with the fibers intermixed, opening the seal requires either cutting the fiber optic bundle 1 or removing the fibers from the collar 4. In either case the seal's unique fingerprint is destroyed. The random orientation, striation marks and complexity of the lit fiber ends insures the uniqueness of the seal fingerprints, and makes it highly improbable that the seal can be replaced in the field without indications of tampering. FIG. 2a illustrates the basic concept of the present invention. Reference numeral 10 generally indicates a first connector having a lower cylindrical portion 12 and an upper cylindrical portion 14 separated by an intermediate stepped down portion 16. An axial bore 18 is longitudinally formed through the entire connector 10 and receives a fiber optic bundle which is doubled up, at its ends, within the connector 10. The free ends of the fiber optic bundle appear at opening 20 in the connector 10. A second connector, generally indicated by reference numeral 22, receives the connector 10 when the seal is closed. A recess is formed in the connector 22 to match the surface configuration of the connector 10. Thus, recess portion 24 receives the lower cylindrical portion 12. In a similar manner the recess 26 receives the cylindrical portion 14 of connector 10. A central recess 28 is formed in connector 22 to receive a split retainer ring 32 which is positioned around the stepped down portion 16 of connector 10 prior to installation or closing of the seal. During installation, the entire connector 10 is pushed into the connector 22 and the split retainer ring 32 is forced outwardly to expand within the recess 28 of connector 22. Locking action between the connectors 10 and 22 are thus achieved. A first length of the fiber optic bundle is indicated at 34. An outward end of this bundle length appears at opening 20 in connector 10 while the intermediate length of the fiber optic bundle is spread out and intertwined, as shown at 36, around the outside of the connector 22. The fiber optic bundle is then returned along length 38 to the connector 10 where its outward end is also positioned at opening 20. Opening 30 in the connector 22 coincides with the opening 20 in connector 10 after the seal is closed by simply pushing the connector 10 into connector 22. Thus, it is possible to position a viewer 40 against the opening 30. The viewer may operate in the same manner as discussed in the mentioned co-pending application. Briefly, a light source shines light through one-half of the opening 30, thus impinging on approximately half of the optic fiber ends as shown more clearly in FIG. 2b. This is accomplished by a light splitting technique disclosed in the co-pending application. The remaining half of the optic fiber ends terminate at 30 in a viewing plane whereby a "fingerprint" may be inspected. If any of the strands or optic fibers are cut after the seal is installed, a change in the "fingerprint," from the time of installation, to the time of inspection, will become manifest thereby indicating tampering. FIG. 3 illustrates a first embodiment of the invention wherein protective covering of the exposed optic fibers is achieved. Referring to FIG. 3 a connector 42 is generally illustrated as a cylindrical member having a first cylindrical portion 44 which steps down to a second cylindrical portion 46. A fiber optic bundle 48 is received within the connector 42. The outwardly illustrated sheathing of the fiber optic bundle 48 terminates within a recess 50 of the connector 42. Individual optic fibers 80 extend longitudinally intermixed through the connector 42 up to the opening 54 where the co-planar ends of individual optic fibers 52 appear. A chamfered split retaining ring 56 is received within an annular recess formed in the cylindrical portion 44 of connector 42. The connector 42 has a shoulder 58 which separates the cylindrical portions 44 and 46. The shoulder mounts a locating pin 60 which is received in a mating recess 84 which is formed in the enlarged connector 62. The connector 62 has the advantage of protectively covering an intermediate length of the individual optic fibers. The connector 62 has a cylindrical wall 64 that is hollow on the inside and is bounded on a lower surface by a disc 66. An opening 67 is formed in the disc 66 to receive the connector 42. A second opening 68 is formed in the disc 66 to permit the passage of the optic fiber bundle through the disc 66 where individual optic fibers are unraveled from the bundle and are wrapped around a cylindrical stepped member 70 which mates with the connector 42. Individual optic fibers are then returned through opening 68 and the length of the bundle to the opening 54 so that a complete loop is effected. The individual optic fibers are secured and protectively covered in the hollow between the cylindrical wall 64 and the cylindrical stepped member 70 by a layer or layers (not shown) of epoxy or other suitable bonding material. Bores 74 are formed in the disc 72 to permit locating pins (not shown) on a viewer, as described in connection with FIGS. 2a and 2b, to be positioned in precise registry with an opening 86 in the connector 62. The disc 72 has a centrally located bore 76 formed therein for receiving the cylindrical portion 46 of connector 42. By providing the bores 74, precise registry may be obtained between a viewer and the opening 54 in connector 42, when the seal of FIG. 3 is closed. An additional inspection facility is provided by intentionally breaking some of the optic fibers during preassembly of the seal. These individual fibers such as 82 are terminated in an annular window 78 that surrounds the opening 86. Accordingly, a fingerprint may then be obtained at the opening 54 of connector 42 as well as the annular window 78 in connector 62. If tampering were to occur by drilling through disc 72, this would probably cause the breakage of optic fibers 82. Although this might not be detected by the breakage of optic fibers at 81, it would be detected by the breakage of optic fibers 82 thereby altering a "fingerprint" appearing at window 78. As in the illustration of FIGS. 2a and 2b, the seal is easily installed in the field by simply pushing the connector 42 into engagement with the connector 62 thereby causing the split retaining ring 56 to expand within the connector 62 thereby locking the connectors 62 and 42 together. FIG. 4 shows a second embodiment of the invention with slightly modified connectors 88 and 90. As will be observed, these connectors generally resemble their corresponding connectors shown in FIG. 3. However, in order to make it more difficult for the insertion of a tool into a closed seal for purposes of releasing a retainer ring, a stepped down cylindrical recess 92 is formed inwardly of the connector 88. The connector 90, when compared with the connector 42 of FIG. 3, includes an additional cylindrical portion 94 which is received within the recess 92. An opening 96 is formed in a disc 98, the latter being epoxied or otherwise attached to the enlarged cylindrical portion 94. The opening 96 receives a corresponding end of the fiber optic sheath for securing the sheath. Individual optic fibers extend axially to an upper end of the connector 90, as in the case of connector 42 in FIG. 3. An opening 100 exists in connector 90 and receives individual spread out strands of the optic fiber bundle therein. The purpose of spreading out the optic fibers in the opening 100 is to position exposed optic fibers in a manner in which they will be cut if a drill or other tool is forced into a closed seal through the disc 98, in a direction toward the split retainer ring 102. From the above description, it will be appreciated that the improved embodiments of the present invention make it easier to use a fiber optic seal in the field due to the preassembly thereof prior to installation on an article to be locked. In order to install the device as a seal, all that need be done is the insertion of one connector into another. I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious modifications can be made by a person skilled in the art.
The invention is directed to a security device which detects tampering with secured closure. A fiber optic bundle is looped through a closure and secured at opposite ends of the bundle to a snap-together connector. An intermediate length of the fiber optic bundle surrounds the snap-together connector preventing access to its locking mechanism unless fibers are severed. After installation, light is passed through the fiber optics and a particular pattern is generated at a viewing end of the connector. Tampering with the closure will cause individual fiber optics to be disturbed or cut so that subsequent viewing of the fiber optics will generate a different viewing pattern than originally observed.
8
BACKGROUND OF THE INVENTION [0001] The invention relates to a screen for cleaning a fiber suspension. [0002] Screens are machines used in the paper industry to clean a pulp suspension comprising water, fibers, and dirt particles. Here a feed flow runs through a screening device, where the accept flow, consisting of water and fibers, flows through the screen. A partial flow, known as the reject and-consisting of water, fibers, and dirt particles, is generally removed at the opposite end to the feed flow. Thus, the solids particles present in the liquid are separated from one another in the screens. By contrast, in filtration processes the liquid is separated from the solids. [0003] In general, a screen of this type is rotationally symmetrical and consists of a housing with a feed device mounted at a tangent, a cylindrical screen basket, normally with perforations or vertical slots, and a rotating rotor. The purpose of the rotor is to keep the screen slots clear, achieved by the vanes rotating close to the screen surface. The accept is collected in a so-called accept chamber, which often has a conical design, and drawn off from here in radial direction. The reject flow is generally brought to a reject chamber, which is usually annular, located at the opposite side of the screen basket to the inlet, and drawn off from here at a tangent. [0004] A screen of this type is known, for example from U.S. Pat. No. 4,268,381. [0005] Other screens known are described in, for example, EP 1 122 358 A2, EP 1 124 002 A2, and EP 1 124 003 A2. [0006] In the screens according to EP 1 122 358 A2, EP 1 124 002 A2, and EP 1 124 003 A2, the following measures are implemented, particularly in order to improve flow conditions: [0007] An additional screen basket is provided in the feed area for pre-screening. [0008] In the feed area between the pipe socket and the freely accessible end of the rotor there is a stationary mounting, particularly a cone, truncated cone, hemisphere, spherical segment, spherical segment between two parallel circles, paraboloid, or a hyperboloid of two sheets. [0009] The accept chamber is designed as twin cones, widening in flow direction of the pulp suspension and tapering again from the mouth of the accept outlet in a conical shape towards the reject outlet. [0010] In these known screens the rotor is designed for even flow onto the screen and is parabolic in shape so that the axial flow speed inside the screen basket remains constant at an assumed uniform flow through the screen basket. As an alternative, a cone shape can be used to come closer to the parabolic shape of the rotor. [0011] It is also known that screens can be designed as multi-stage units, comprising several separation stages one after another. [0012] The screens known from the state of the art, however, still hold disadvantages. In particular, the flow conditions at the reject outlet leave much to be desired. SUMMARY OF THE INVENTION [0013] The present invention aims to provide a screen in which a further improvement can be attained in the flow conditions and thus, a reduction in the energy applied, while increasing production and dirt separation. [0014] The screen according to the invention is characterised by the reject outlet being located in the vicinity of the maximum rotor diameter and by at least one feed for dilution water being located at the reject outlet, particularly immediately below it. [0015] As a result, the reject being discharged is diluted with water. This dilution has a favorable effect, particularly in a multi-stage screen design, where the reject from one stage is also the feed to the following stage. [0016] One or more feed points for dilution water can be provided, located on the housing of the separation or at the screen basket, and/or on the rotor. If the dilution water feed is located at the rotor, this feed is preferably supplied through a pipe mounted inside the rotor. [0017] The dilution water feed, or several feed points if required, can be oriented such that the dilution water enters in rotor running direction and/or in the opposite direction to that in which the rotor rotates. [0018] As a result, the rotating movement of the pulp suspension can be reduced. Loosening of the suspension can be improved by this turbulence applied to it. [0019] A further preferred embodiment of the screen according to the invention is characterised by one or several devices to interrupt the axial flow being located in the vicinity of the maximum rotor diameter. [0020] In the following, the term “devices” (plural) is used, relating also to screens according to the invention which have only one device to interrupt axial flow. [0021] Depending on their origin and type (recycled fibers, fresh fibers, etc.), pulps contain differing amounts of dirt particles. To ensure stable screen operations, certain minimum amounts of carrier medium (reject amounts) must be set as a function of the dirt and flake content, and of the suspension's rheological characteristics. [0022] It has proved favorable to mount devices to interrupt the axial flow at the same height as the maximum rotor diameter in order to guarantee stable screen operations. [0023] The devices to interrupt axial flow can be mounted at the housing of the separation unit or at the screen basket and/or at the rotor of the screen. Thus, a design in which devices to interrupt the axial flow are provided on both sides (i.e. both at the housing and at the rotor) is also possible. [0024] The devices should preferably be one or several axial flow interruption rings. Depending on its design, the flow interruption ring can either be continuous or in the form of individual segments, or have gaps. [0025] The flow interruption ring (or flow interruption rings) can be of adjustable design, such that the size of the opening created by the flow interruption ring for the reject can be modified. [0026] The flow interruption ring can be of adjustable design, for example in the same way as an iris diaphragm. In addition, the flow interruption ring can be adjustable statically (e.g. in the form of statically adjustable ring segments). [0027] The outer diameter of a flow interruption ring on the rotor side preferably has a toothed profile. [0028] In a further preferred configuration of the screen according to the invention, at least one feed for dilution water is coupled to a device for interrupting the axial flow. For example, the feed of dilution water can protrude into the area between housing and rotor and thus, serve as a device for interrupting the axial flow. [0029] Particularly in multi-stage screens, thickening of the suspension takes place on the one hand in the inflow area to the screen surface as the suspension flows between the first and the final screening stage, and on the other hand, the flake content becomes more concentrated. [0030] In order to maintain the screening effect, the suspension consistency, as described above, is set by means of intermediate dilution. It has proved favorable to counteract this concentration of the flake content by inserting a deflaking unit. [0031] Thus, the separating unit of the screen according to the invention should preferably contain a deflaking unit. Advantageously, the deflaker should take the form of one or several rings mounted on the housing or screen basket and/or on the rotor. The shape of the mountings used corresponds to models that are already known in themselves, while additional hydraulic guiding elements can be included in order to set differential pressures. [0032] The screen according to the invention can preferably comprise two or more separation units located one after another in a manner already known, where all separation units have one common rotor, which has a parabolic or parabolic segment shape for each separation unit, adapted to the flow conditions in the separation unit in each case. [0033] The height of each separation unit should preferably be at least twice the sum of the heights of all separation units adjoining the separation unit in question, i.e. in a screen with three separation units, the height of the first stage is at least ⅔ the overall height of the unit and the height of the second stage is at least {fraction (2/9)} of the overall height. [0034] Each separation unit of a multi-stage screen according to the invention should preferably contain one or more devices to interrupt the axial flow, as described above, in the vicinity of the maximum rotor diameter. [0035] Similarly, it is preferable to have at least one inlet for dilution water in each separation unit in the vicinity of the reject outlet or underneath it. [0036] In a multi-stage screen, the feed for dilution water can be located in the lower delimitation of the rotor segment of a separation unit so that the dilution water is discharged into the space beneath the rotor segment (and thus into the vicinity of the reject outlet or the area below it). As an alternative or additionally, the feed for dilution water can be mounted in the upper part of the rotor segment of the following separation unit. [0037] In a multi-stage screen according to the present invention with at least three separation units, a minimum of one deflaking unit should preferably be provided, particularly at the transition from the second to the third separation unit. [0038] In addition to the features described above, the screen according to the invention should preferably contain one or several features of the screens described in EP 1 122 358 A2, EP 1 124 002 A2, and EP 1 124 003 A2. BRIEF DESCRIPTION OF THE DRAWINGS [0039] The present invention may be better understood and its numerous objects and advantages will become apparent to those skilled in the art by reference to the accompanying drawings in which: [0040] [0040]FIG. 1 is a view of a screen according to the state of the art; [0041] [0041]FIG. 2 is a view of a multi-stage screen according to a preferred configuration of the present invention; [0042] [0042]FIG. 3 is an enlarged section of a reject outlet from the screen according to FIG. 2; and [0043] [0043]FIG. 4 is an enlarged section of an alternative design of a reject outlet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0044] The screen according to FIG. 1 comprises, in a way already known, a feed branch 2 , through which a pulp suspension is fed for cleaning purposes. In the feed area, a mounting 3 is provided, which is shown here as a truncated cone. The pulp suspension enters the space between the parabolic rotor 4 and the screen 5 and is conveyed through the screen into the accept chamber 6 . The housing of the accept chamber is designed as a double cone in this configuration and in a way which is generally known. The accept outlet is marked with reference number 7 . The reject is removed through a reject outlet 8 . [0045] In FIG. 2, those devices or parts of devices that are identical to the configuration which is state of the art and shown in FIG. 1 are marked with the same reference numbers. In the preferred configuration of a screen according to the invention and as shown in FIG. 2, the screen 1 consists of three separation units 1 ′, 1 ″ and 1 ′″. [0046] The three separation units 1 ′, 1 ″ and 1 ′″ have one common rotor, whose sections 4 ′, 4 ″ and 4 ′″, respectively, adapted to the flow conditions in the corresponding separation unit, are parabolic or have the shape of a truncated paraboloid. As an alternative, the sections of the rotor can also be shaped similar to a truncated cone or a parabola. [0047] Each separation unit has a reject outlet ( 9 ′, 9 ″ and 9 ′″). The reject from the first and second separation units is thus also the feed to the next separation unit in each case. The reject from the third and final separation unit is drawn off through the reject outlet 8 . [0048] In FIG. 2, a pipe for dilution water mounted inside the rotor is marked 10 and the outlets from the pipe will be described in more detail below. [0049] A deflaking unit 13 is provided at the transition from the second to the third separation unit. [0050] [0050]FIGS. 3 and 4 show preferred configurations of a reject outlet (in this case reject outlet 9 ′) in an enlargement of the section marked with a chain-dot line in FIG. 2. [0051] According to the configuration in FIG. 3, feed points for dilution water 10 a ′, 10 b ′, and 10 c ′ are provided on the housing, as well as at rotor sections 4 ′ and 4 ″ in the vicinity of the reject outlet 9 ′ and beneath it. [0052] The feed point 10 a ′ is located in the lower delimitation of the rotor segment 4 ′ of the first separation unit 1 ′. The feed point 10 b ′ is placed in the upper section of the rotor segment 4 ″ of the second separation unit 1 ″. The feed points 10 a ′ and 10 b ′ can be supplied through a pipe 10 (see FIG. 2) mounted inside the rotor. [0053] The feed point 10 c ′, for example, is located in the vicinity of a flange 11 between the first separation unit 1 ′ and the second separation unit 1 ″ and is supplied through a pipe not shown in this illustration. [0054] With the feed pipes for dilution water 10 a ′, 10 b ′ and 10 c ′, the consistency of the pulp suspension flowing to the next separation unit can be controlled effectively. [0055] In addition, the configuration shown in FIG. 3 has an adjusting ring 12 a ′ mounted at the lower end of the rotor section 4 ′. The adjusting ring can have an adjustable mounting, as explained above, e.g. in the shape of an iris diaphragm (indicated by the double arrow). The outer diameter of the adjusting ring or its segments should preferably have a toothed profile. [0056] With the adjustable ring 12 a ′, the axial throughput can be controlled by means of the reject outlet 9 ′. [0057] The configuration of the reject outlet 9 ′ shown in FIG. 4 differs from the configuration shown in FIG. 3 in that a flow interruption ring 12 b ′ is mounted on the housing in addition to the adjusting ring 12 a ′. The housing side feed 10 c ′ for dilution water is also located in the flow interruption ring 12 b ′, i.e. the feed for dilution water and the flow interruption ring are coupled to one another. Of course, the configuration in FIG. 4 can also include additional feed lines for dilution water at the rotor, as shown in FIG. 3. [0058] While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.
A screen, for cleaning a fiber suspension, includes at least one separating unit containing a housing, a parabolic rotor, a screen basket, an accept chamber, and a reject outlet. The reject outlet is located in the vicinity of the maximum rotor diameter. The screen also includes at least one feed for dilution water located in the vicinity of the reject outlet, particularly directly below it.
3
This is a continuation, of application Ser. No. 743,478, filed Nov. 19, 1976 now abandoned. FIELD OF THE PRESENT INVENTION The present invention relates to a drying apparatus, and more particularly but not exclusively to drying apparatus for use with a printing machine for drying newly printed material, such as paper sheets, fed from the printing machine. The drying apparatus will include conveying means in the form of a carrier effective to carry said material through the machine. In addition means are provided which counteract any tendency of the material to shrink or to change its shape in any other way as a result of being dried in the drying apparatus. BRIEF DESCRIPTION OF THE PRIOR ART Printing machines are known to the art in which material provided with printing ink, such as newly printed sheets of paper, is dried in a drying apparatus and then cooled in a cooling section of the drying apparatus. It is also a known fact, however, that printed material treated in a drying apparatus, in which printing ink on the material is dried by subjecting said ink to streams of warm or heated air or black radiation, i.e. infra-red radiation, is also caused to change its shape as it passes into the heating section of the drying apparatus due to the exchange of moisture from said material to the air. Subsequent to being dried in the heating section of the drying, apparatus, the printed material is passed to a cooling section of the drying apparatus in which air at ambient temperature or chilled air is blown onto the material. Although not particularly restricted thereto, hereinafter the printed material will be referred to as a paper sheet, in order to simplify the following description of the apparatus. It will readily be perceived that when the paper sheet, passes the heating sections of the drying apparatus, in which drying is effected by means of hot air which, as a result of it being heated, contains very little moisture, not only is the printing ink on the sheet by the hot air dried, which printing ink has a relatively high moisture content, but also the paper sheet itself, which paper sheet also has a relative high moisture content. It will thus be apparent that, during its passage through the drying apparatus, the paper sheet must lose some of its moisture content of the sheet to the air, causing the physical measurements of the sheet to change, as by shrinking for example. It is therefore desirable to ensure that, during its passage through the drying apparatus, the sheet neither transmits moisture to the air nor loses moisture thereto whilst effectively drying the printing ink. One solution in this respect would be to cause the humidity of the heating sections of the drying apparatus to be so high as to coincide or substantially coincide with the moisture content of the paper sheet, thereby preventing the transport of moisture from the sheet to the air. Another solution would be to replace moisture passing from the sheet to the air during transportation of the paper sheet through the heating sections of the drying apparatus to a subsequent cooling section. The task of supplying large quantities of moist air to the paper sheet is able to absorb the moisture which it has lost in the heating sections of the drying apparatus, has been found very difficult to realise in practice. In practice the length of a drying apparatus incorporating means for putting this latter solution into effect will be twice as long as a conventional drying apparatus in which no means for moisturing the sheet in the cooling section are provided. The proposal to supply air to the drying apparatus of such humidity as to coincide with or substantially coincide with the moisture content of the paper sheet, thereby preventing the transport of moisture from the paper sheet to the air, has been found to present a number of problems. The moisture contained in the heated air in the drying apparatus, together with solvent absorbed by the air from printing ink, is liable to cause considerable amount of condensation in the airoutlet pipe when the air and solvent leave the drying apparatus. To solve this problem, it would be necessary to heat the air-outlet pipe, as a whole, to a temperature equal to or only just below the temperature of the drying apparatus. It has been assumed that the use of moist air in the drying apparatus will provide a poorer drying effect that would dry air. This assumption is not particularly well founded, especially in view of the fact that moist air has a higher transition number than dry air, hence the drying ability of moist air and of dry air would be practically the same. The primary reason why moist air has not previously been used in the heating section of a drying apparatus, is because moist air has a much higher heat content than dry air and if air exhibiting a high heat content is permitted to pass freely to the ambient air, the amount of energy consumed in such a drying apparatus would be considerable. It will thus readily be perceived that a solution proposing the use of moist air in the heating sections of such a drying apparatus would be encumbered with difficult problems. It is previously known to use in a drying apparatus, and particularly in drying apparatus intended for printing machines, such as silk-screen printing machines, a heat exchanger, to reduce the amount of energy consumed in the drying apparatus. OBJECTS OT THE PRESENT INVENTION Present day highly developed printing machines, which may operate at very high printing speeds, require progressively more effective drying apparatus. Since the air used for drying purpose absorbs therein gases given off by the print etc. on the sheets as they are dryed, the air cannot be re-used in the drying apparatus, but must be removed therefrom. In order to conserve energy in the drying apparatus, it is necessary for the energy content of air used for a drying operation to be transferred to the air intended for a further drying operation. By such transfer of the energy or heat content of the air, air which is intended for a subsequent drying operation can be pre-heated, thereby effectively reducing the amount of energy which need be supplied to the drying apparatus. When the heating section or sections of a drying apparatus are to use moist drying air, it is therefore necessary to transfer as large part as possible of the energy content of the used air to fresh air intended for a subsequent drying operation. Primarily this means that the moisture in the air which has been used for a preceding drying operation shall be transferred to air intended for a subsequent drying operation. An object of the present invention is to provide a drying apparatus which fulfills the aforementioned desiderata. Accordingly, this invention consists in a drying apparatus particularly intended for drying a printed material fed from a printing machine, preferably a paper sheet, including a conveying means in the form of a carrier effective to carry said material through said machine, and having means for counteracting any tendancy of the material to shrink or change its shape as a result of being dried by the drying apparatus, in which the air used in the drying apparatus is given, via means arranged therefore, a relative moisture constant which is so adapted to or substantially so adapted to the moisture content of the material that said material, during the drying process, is not subjected to shrinkage or change in shape, or is only subjected to such shrinkage or change in shape to a slight degree. BRIEF DESCRIPTION OF THE DRAWINGS So that the invention will be more readily understood and further features thereof made apparent, an embodiment of the invention will now be described with reference to the accompanying schematic drawings in which FIG. 1 is a partly sectional view in perspective of a drying apparatus comprising a heating section and a cooling section and a conveyor belt extending between said sections, FIG. 2 is a horizontal sectional view of a first part of the heating section of a drying apparatus according to FIG. 1, while FIG. 3 is a horizontal sectional view of a second part of the heating section of a drying apparatus according to FIG. 1, FIG. 4 is a side view in section of the principle construction of the heating section of a drying apparatus utilizing a heat exchanger, and FIG. 5 shows the principle construction of a unit with moist air. DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 of the accompanying drawings there is thus shown an arrangement which, in accordance with the invention, is intended to counteract changes in shape, such as shrinkage, of a papersheet provided with printing ink, during the passage of said papersheet through a drying apparatus, said papersheet being conveyed from a printing machine (not shown) to a conveying means 1 extending through the entire drying apparatus. The drying apparatus shown in FIG. 1 exhibits a multiplicity of drying sections or heating sections 2 and a terminal cooling section 3. Subsequent to being printed in the printing machine, the paper sheet 1' is conveyed to the conveying means 1 and is passed through the heating sections 2, in which the sheet 1' is exposed to a stream of hot, moist air. The construction of the heating sections 2 will be described in more detail hereinafter. Subsequent to passing the heating sections, the paper sheet 1' is passed to the cooling section 3, in which the sheet is exposed to a stream of cold air delivered by a fan 3a arranged in said cooling section 3. The fan 3a is arranged to draw air from an inlet 3b and to force the air through a multiplicity of air channels 3c. Holes 3c are shown to be above the belt 1 in FIG. 1. When these air channels 3c are arranged beneath the conveyer belt 1 as is the case of the FIG. 1 embodiment it is convenient to provide the conveyor belt 1 with air holes or for the conveyor belt to have the form of an air-permeable cloth. There is nothing to prevent, however, the stream of air from being directed onto the upper surface of the paper sheet from above. In certain instances it may be suitable for the cooling section 3 to cooperate with a single moistening system, so that the air leaving the cooling section obtains a relative humidity which is slightly higher than the relative humidity of the ambient air. Such a mositening system is referenced in FIG. 1. The moistening system 4 is arranged to communicate with the inlet 3b of the cooling section through a pipe 4a. The inlet 3b has the form of a box and is connected, by means of drainage pipe 4b, with the moistening system 4. Water is supplied to the moistening system 4 through a pipe 4c and the supply of water is controlled by a magnet valve 4d associated with said pipe 4c. Conveniently, the paper sheet is so turned that the moist, cooling air is applied to the plain side of said sheet i.e. the side thereof which has not been printed upon in a immediate preceding printing operation. FIG. 2 shows the heating sections of the drying apparatus according to FIG. 1, in which a coating, such as printing ink, on a printed paper sheet is to be dried. As previously mentioned, the printing machine may have the form of a silk-screen printing machine so arranged that the printed sheet of material is fed directly from the machine onto the conveyor belt 1 and thence into the heating sections 2. The printed paper sheet 1' is inserted into the heating section in the direction shown by the arrow A in the drawing. Subsequent to the paper sheet passing onto the conveyor means 1 it is conveyed into the section 2. In the illustrated embodiment, the heating section comprises there part section 2, 2a and 2b, although the number of part-sections used may be more or less than three. Subsequent to passing through the part-section 2, 2a and 2b the paper sheet is passed to the cooling sections 3. The sheet 1' is then conveyed by the conveyor belt 1 to a depositing device shown to the left in FIG. 1. The depositing device does not form part of the present invention and has consequently not been shown in detail in the drawing. The heating section of the drying apparatus is arranged to dry the printing on a paper sheet with hot air (having a temperature of 50°-80° C.). To this end, the section 2 is provided with a fan 7, the input side 7a of which communicates with a fresh-air inlet opening 8d via passages 8, 8a, 8b and 8c. An air-moistening unit is incorporated in a passage 9, the construction of said unit being described in more detail hereinafter. The opening 8d is provided with a grid-like structure and a filter or the like. The fan 7 is arranged to pump fresh air through the passage 9, which is provided with a regulating valve, such as the butterfly valve 9a shown in the Figure. Conveniently, the passage 9 may be provided with a heating elements 10. In the exemplaray embodiement it is assumed that the heating elements are electrically operated (the input power may be of the order of magnitude of 30 kW). Subsequent to the air being heated by elements 10 (which are normally located beneath the conveying belt 1), air is fed from the fan 7 to nozzles placed above the conveyor belt and directed towards the paper sheet thereon and towards that part of the paper sheet which has been printed upon. The air, thus heated, is permitted to pass through the conveyor belt and, by means of a fan 11 located in partsection 2a, is drawn into the section 2 through a passage 12, the air drawn into the section 2 through a passage 12, the air being fed through a passage 13 provided with a valve 13a to further heating devices 14. These heating devices 14 are also electrically operated. (They may have a power corresponding approximately to 5 kW). This heated air is also passed to above the conveyor belt and blown down against the printed sheet. As shown in FIG. 3, the heated air in the partsection 2a passes through the conveyor belt and is drawn, by a fan 15, through a passage 16 from where it is fed through a further passage 17, having a valve 17a arranged therein, through a still further passage 17b to the upper side of the part of the conveyor belt, referenced 19 in FIG. 4. The part section 2b is shown partly in section and in simplified construction in FIG. 4. The passage 17b branches into a multiplicity of ejection nozzles 17c. The conveyor belt 1, or that part thereof referenced 19 in FIG. 4, is carried by a multiplicity of rollers 19a which move in the direction shown by the arrow in FIG. 4. All heating sections 2, 2a, 2b of the illustrated embodiment are identical in construction. By means of a fan 20 place in partsection 2b air used in a drying operation is drawn through an inlet opening 21a into a heat exchanger 21. The heat exchanger 21 comprises a rotatable drum 21b mounted for rotation on a shaft 21c. The drum exhibits a multiplicity of heatabsorbing grid-like structures or cells and air used in a previous drying operation passes to the heat exchanger from right to left as seen in FIG. 4. The drum 21b is rotated by a motor 22 as air used in a preceding drying operation is passed to the heat-absorbing gridlike structures. The air used for drying the print on a sheet of material in section 2b is drawn by the fan 20 through the heat exchanger 21 and passes, via a passage 23 and a valve 23a, out through an opening 24, which may be provided with a grid-like structure 25 and a particle-separating filter device. As previously mentioned, the air intended for a subsequent drying operating shall be allowed to pass through the heat exchanger 21, this being effected through passages 8c and 8b. Fresh air is introduced through grid-like structure 8e and is heated in the heat exchanger 21, the pre-heated air being passed through passages 8b, 8a to the fan 7. In this way the input energy of heating means 10 can be reduced, as can also the input energy of heating means 14. It should be observed that when passing through the heat exchanger 21 the air used in a preceding drying operation and air intended for a subsequent drying operation shall pass through the heat exhanger on respective sides of the shaft 21c. It should also be observed that used air present in the heat exchanger cells must first be removed from the grid-like structure or cells of the heat exchanger before this part of the heat exchanger contacted by said used air is exposed to the air intended for a subsequent drying operation, thereby to prevent exhaust gases extracted by the used air from the printing ink, for example, entering the fresh air. The used air can be removed by arranging that the absorbing grid-like structures is free before they are transferred to emit heat to the air intended for a subsequent drying operation. That zone of the heat exchanger which is free between the used air outlet and the fresh air inlet is also designated the purifying zone, said purifying zone being located immediately above the shaft 21c, as shown in FIG. 3. In accordance with the invention, the heat exchanger is provided with a water or moisture absorbing material, the used air transferring moisture and heat to the heat exchanger whilst the fresh air takes up moisture and heat therefrom. Since the heat exchanger has the form of a rotatable drum provided with heat-absorbing portions, for example in the form of cells of grid-like structure, the moisture or water-absorbing material can be arranged between the grids. The water-absorbing material may conveniently comprise paper, such as blotting paper. Arranged in the passage 9 is an air-moistening unit 51. The unit 51 is arranged to impart to the moist air used in the heating section of the drying apparatus a relative humidity which is so adjusted to or substantially so adjusted to the moisture content of the sheet that the sheet during the drying process in the heating sections 2-2b will not absorb or lose moisture, or will only give off moiusture and lose moisture to a very slight extent. To this end, the invention includes a moisture-regulating device 52 which is connected to an air-moistening unit incorporated in the drying apparatus via a connecting line 53. The moisture-regulating device 52 is arranged to bring into operation different sections of the air-moistening device 51 in dependence upon the relative humidity of the air surrounding the drying apparatus, which is measured by a sensing device 54 connected to the moisture-regulating device via a line 54a, which the relative humidity in the drying apparatus is measured by a sensing device 55 connected to the moisture-regulating device 52 via a line 55a. The moisture-regulating device is arranged to operate in conjunction with a indicator 52a, from which the relationship between the relative humidities evaluated by the sensing device 54 and the sensing device 55 can be read off. By means of a setting device 52b and 52c respectively it is possible to regulate the relationship between the relative humidites to a predetermined value. Conveniently the moisture-regulating device 52 may be arrange to maintain the relative humidity in the heating section of the drying apparatus via the sensing device 55 at the same or substantially the same level as the realtive humidity of the ambient air via the sensing device 54. The moisture-regulating device 52 is arranged to control the air-moistening unit 51 via a line 53. The line 53 passes to an electronic apparatus 51a which is constructed in a manner known per se such that, in response to a signal on the conductor 53, it energises one or more of the sections of the air-moistenting device, said sections being designated 510-513. The air-moistening device 51 may conveniently be constructed to provide an air-humidity of one and the same relative value through passage 8a irrespective of the humidity of the air entering through passage 8b. This is effected by causing different sections to be made operative. FIG. 5 showns how sections 510, 511 and 512 are operative while the section 513 is inoperative. This means that when the moisture-regulating device 52 requires a higher relative humidity in the heating section 2, a further section 513 of the air-moistening unit is made operative, while, on the other hand, when the moisture-regulating device 52 requires a lower humidity in the heating section 2, a section, such as section 512, of the air moistening unit 51 is made inoperative. The invention is naturally not restricted to the aforedescribed embodiments but can be modified within the scope of the accompanying claims.
There is provided a drying apparatus, which is particularly intended for drying the print on printed paper sheets for example, subsequent to said sheets leaving a printing machine. Means are provided for applying to the wet, printed surface heated air having a moisture content, which is at least substantially equal to the moisture content of the paper sheet. A heat exchanger is arranged to remove moisture from the used air exhausted from the system and to transmit this extracted moisture to fresh air drawn into the heat-exchanger for a subsequent drying operation.
5
STATEMENT OF GOVERNMENTAL INTEREST The Government has rights in this invention pursuant to Contract No. N00024-85-C-5301, awarded by the Department of the Navy. BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a method and apparatus for using an electromagnetic technique to monitor physiological changes in the brain. More particularly, the invention uses an electromagnetic field to non-invasively measure impedance changes at localized points within an animal or human brain. For example, these localized impedance measurements can be used to detect and monitor the advent and growth of edematous tissue, or the process of hydrocephalus. 2. Description of the Prior Art It is important in diagnosing and treating various life-threatening conditions, such as brain edema and hydrocephalus, to monitor the time-trends of physiological changes in the brain. Brain edema, which is an increase in brain volume caused by grey and/or white brain tissue absorbing edematous fluid, can develop from general hypoxia; from cerebral hemorrhage, thrombosis, or embolus; from trauma (including post-surgical); from a tumor; or from inflammatory diseases of the brain. Brain edema can directly compromise vital functions, distort adjacent structures, or interfere with perfusion. It can produce injury indirectly by increasing intracranial pressure. In short, brain edema is often a life-threatening manifestation of a number of disease processes. There are several effective therapeutic measures to treat brain edema. These include osmotic agents, corticosteroids, hyperventilation to produce hypocapnia, and surgical decompression. As with all potent therapy, it is important to have a continuous measure of its effect on the manifestation, in this case, the brain edema. All current techniques for measuring physiological changes in the brain, including the manifestation of brain edema, have shortcomings in providing continuous or time-trend measurements. Intracranial pressure can be monitored continuously, but this is an invasive procedure. Furthermore, intracranial compliance is such that substantial edema must occur before there is any significant elevation in pressure. When the cranium is disrupted surgically or by trauma, or is compliant (as in infants), the pressure rise may be further delayed. These patients are often comatose, and localizing neurological signs are a late manifestation of edema. Impairment of respiration and circulation are grave late signs. Thus, clinical examination is not a sensitive indicator of the extent of edema. X-ray computed tomography (CT) scanning can produce valuable evidence of structural shifts produced by brain edema, and it is a non-invasive procedure. Structural shifts, however, may not correlate well with dysfunction, especially with diffuse edema. Furthermore, frequent repetition is not feasible, particularly with acutely ill patients. NMR proton imaging can reveal changes in brain water, it does not involve ionizing radiation, and it is non-invasive. However, it does not lend itself to frequent repetion in the acutely ill patient. PET scanning can reveal the metabolic disturbances associated with edema and will be invaluable in correlating edema with its metabolic consequences. However, it too is not suited to frequent repetition. For these reasons it would be a significant advance to have a measurement which (1) gives reliable time-trend information continuously; (2) is non-invasive; (3) does not depend upon the appearance of increased intracranial pressure, and (4) can be performed at the bedside even in the presence of life-support systems. As will be discussed in detail subsequently in this application, Applicant has related localized impedance changes in the brain with physiological changes in the brain. Applicant was the first to identify that edematous tissue has a significantly different conductivity from healthy white or grey matter. To non-invasively detect such an impedance change, Applicant has invented a method and apparatus which uses an electromagnetic field for sensing such an impedance change at localized portions of the brain. U.S. Pat. No. 3,735,245 entitled "Method and Apparatus for Measuring Fat Content in Animal Tissure Either in Vivo or in Slaughtered and Prepared Form", invented by Wesley H. Harker, teaches that the fat content in meat can be determined by measuring the impedance difference between fat and meat tissue. The Harker apparatus determines gross impedance change and does not provide adequate spatial resolution for the present use. As will be discussed in detail later, brain impedance measurements must be spatially localized to provide a useful measure of physiological changes. A general measurement of intracranial conductivity would not be revealing, since as in the case of brain edema, the edematous fluid would initially displace CSF fluid and blood from the cranium; and, since these fluids have similar conductivities, a condition of brain edema would be masked. U.S. Pat. No. 4,240,445 invented by Iskander et al teaches the use of an electromagnetic field responsive to the dielectric impedance of water to detect the presence of water in a patient's lung. The Iskanden et al apparatus generates an electromagnetic wave using a microwave strip line. Impedance changes within the skin depth of the signal will cause a mode change in the propagating wave which is detected by associated apparatus. Therefore, Iskander et al uses a different technique from the present invention and does not detect conductivity variations with the degree of localization required in the present invention. U.S. Pat. No. 3,789,834, invented by Duroux, relates to the measurement of body impedance by using a transmitter and receiver and computing transmitted wave impedance from a propagating electromagnetic field. The Duroux apparatus measures passive impedance along the path of the propagating wave, whereas the present invention measures localized impedance changes in brain matter and fluid by measuring the eddy currents generated in localized portions of the brain matter and fluid. None of the above-cited references contemplate measuring localized impedance changes in the brain to evaluate physiological changes in the brain, such as the occurrence of edematous tissue, and none of the references teach an apparatus capable of such spatially localized impedance measurements. SUMMARY OF THE INVENTION Applicant was the first to discover that edematous tissue has a significantly different conductivity (or impedance) from normal white or grey brain matter. Applicant believes that edematous tissue is formed when white or grey matter in the brain becomes diffused or prefused with edematous fluid by an as yet unknown intercellular or extracellular process. As will be described later, the discovery that impedance changes can be used to identify edematous tissue was made using invasive probes. Applicant generally found that the conductivity change between normal and edematous grey tissue, for instance, would change by as much as 0.14 mho/meter, or equivalently by 100% of the normal value. The present invention detects the increase in conductivity (or decrease in impedance) of brain tissue to locate areas of edematous tissue in the brain. Edematous tissue may occur in localized areas near the surface of the cranium or may occur deeper in the brain. Since edematous tissue swells, blood and CSF fluid in the brain which may have the same conductivity as edema fluid, might be displaced. Therefore, localized spatially discrete changes in impedance must be measured to detect the physiological changes associated with brain edema. Further, monitoring localized impedance changes in the brain will allow one to measure and diagnose hydrocephalus since an increase in the ventricular volume will result in an increase in conductivity in certain localized areas of the brain. This is because CSF fluid which fills the expanded ventricle has a significantly greater conductivity (1.5-1.75 mho/meter) than white matter (0.10 to 0.15 mho/meter) or grey matter (0.12 to 0.23 mho/meter). Applicant also realized that such localized impedance changes can be sensed non-invasively using a magnetic field and detecting the changes in mutual inductance between the brain and a sense coil. The apparatus described herein, and also described in part in a copending commonly assigned patent application entitled "Electromagnetic Bone Healing Sensor" (Ser. No. 753,824), generates a spatially discrete oscillating magnetic field which radiates a pre-selected location of the brain. The magnetic field induces eddy currents in brain tissue and fluid in the radiated area. When these eddy currents collapse, they produce a secondary weak magnetic field which is detected by the apparatus. The magnitude of the eddy currents is proportional to the actual impedance of the tissue and fluid where the eddy currents are generated. The magnitude of the eddy currents in turn directly affect the magnitude of the secondary weak magnetic field. The invented apparatus is capable of detecting small variations in impedance changes and quantitatively measuring such changes. A magnetic drive/sensor means is designed to concentrate the magnetic field in spatially localized areas within the brain. The invention also teaches various techniques for sequentially scanning different pre-selected and localized areas in the brain to generate a composite view of brain impedance. An oscillator detector in combination with the magnetic drive/sensor means is specifically designed to be sensitive to small impedance changes and to reduce polarization effects and background noise which could render such monitoring impossible. It is hoped that continuous monitoring of a patient at his bedside would enable physicians to treat the first sign of swelling and also to measure any therapy's effectiveness. The invented device may prevent much of the brain damage that results from head injuries, stroke, brain tumors or drug abuse when injured brain tissue swells and presses against the inside of the skull. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a table showing the difference in conductivity between normal and edematous white and grey matter found in a rabbit brain. FIG. 2 is a graphic representation of the invented non-invasive principal for measuring brain impedance. FIG. 3 is a block diagrammatic illustration of the present invention showing the use of a drive/sensor loop coil. FIG. 4 is a schematic diagram of a typical oscillator/detector circuit used in the present invention. FIGS. 5a and b illustrate spatial localization within a drive/sensor loop coil by varying the frequency of the exciting electrical signal; FIG. 5a graphically shows the field intensity region for lower frequency excitation; and, FIG. 5b shows the field intensity region for higher excitation frequencies. FIG. 6 is a block diagrammatic illustration of the present invention using a plurality of drive/sensor loop coils to map out local areas of impedance. FIGS. 7a and b illustrate the use of an elliptical drive/sensor coil; FIG. 7a and FIG. 7b illustrate different orientations of the elliptical coil to analyze different areas of the brain. FIG. 8 is a schematic diagram showing a solenoid type drive/sensor coil. FIG. 9 is a graphic illustration showing radius R of higher field intensity for a solenoid coil. FIG. 10 illustrates a bonnet type embodiment to be worn on the patient's head having a plurality of solenoid type drive/sensor coils. FIG. 11 is a block diagrammatic illustration of a bi-static technique as taught by the present invention. FIG. 12 is a schematic block diagram of a typical circuit used for either monostatic or bistatic pulsed excitation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention provides a method and apparatus for making continuous or time-trend measurements of the migration of CSF and edema fluid within brain tissue and of changes in biological substances in the brain. These biological changes within the brain are monitored by observing changes in local conductivity or impedance within the brain. Applicant was the first to discover that edematous tissue has a significantly different conductivity (or impedance) from normal white or grey brain matter. Applicant made this discovery using a two-needle probe to contact portions of fresh frozen rabbit brains thawed to room temperature. The rabbit brains contained edematous regions caused by the previous implantation of a rabbit brain tumor. The two-needle probe was connected to an impedance meter for a display of the local impedance value. Impedance measurements were performed with the insertion of a probe needle into normal and edematous white and grey matter as the frozen brains thawed from 4° to 22° C. As shown, in FIG. 1, the edematous grey and edematous white conductivity values were higher than normal tissue. Applicant believes that the higher conductivity in the edematous tissue is because the tissue becomes diffused or prefused with high conductivity edematous fluid. Similar results were obtained at frequencies from one to four megahertz. FIG. 2 is a schematic representation of a generalized embodiment of the present invention. A drive/sensor coil 10 produces an alternating magnetic field 12. Although the magnetic field intensity lines pass through the brain, the magnetic field intensity lines are more highly concentrated in the plane of the drive/sensor coil 10. The alternating magnetic field (12) generate an electrical field 14 which induces eddy currents in brain tissue and fluid. One such eddy current is graphically represented by element 16 on FIG. 2. The magnitude of the eddy current is proportional to the magnitude of the electric field 14 multiplied by the conductivity of brain tissue and fluid that particular eddy current travels though (i.e., magnitude of eddy current is proportional to E×σ where E is the magnitude of the electric field and σ is conductivity). The eddy current alternates in accordance with the alternating magnetic field 12. The alternating eddy current 16 generates a second weaker magnetic field 18. This magnetic field 18 induces a corresponding E field on the sense coil 10 which is detected and processed by the appropriate circuitry. The sense coil 10 actually detects the secondary magnetic field 18 generated from a multitude of such tiny eddy currents induced in the brain tissue and fluid excited by the primary magnetic field 12. Since we are interested in localized impedance measurements, spatial and temporal techniques are used to either reduce the area of brain excitation by the primary magnetic field 12 or temporally separating the reception of secondary magnetic field 18 from a selected area of the brain. In the generalized embodiment shown in FIG. 2, the drive/sensor loop coil 10 produces some degree of localization by intensifying the magnetic field in the plane of the coil 10. FIG. 3 is a schematic representation of a non-invasive apparatus to measure localized brain impedance as taught by the present invention. The drive/sensor coil is a thin or narrow magnetic field coil winding 20. Oscillator/Detector 22 provides an alternating electric current in coil 20 which produces an alternating magnetic field. As brain tissue and fluid are brought within the proximity of coil 20, the mutual inductance of the coil changes the frequency of oscillation of the oscillator/detector 22. The magnitude of the frequency change is proportional to the value of the electrical conductivity located within the drive/sensor coil 20. In summary, the magnetic field produced by the drive/sensor coil 20 creates an electric field. The electric field creates induced eddy currents within the brain tissue and fluid. These induced eddy currents re-radiate a secondary magnetic field, which is detected by the drive/sensor coil 20 and in effect changes its mutual inductance. The change in mutual inductance of the coil changes the oscillator frequency of the oscillator/detector 22 to correspondingly change. Returning to FIG. 3, a patient's head would be placed through detector coil 20 which non-invasively ascertains the electrical conductivity in a horizontal section of the brain. Oscillator/detector 22 is connected to the coil 20 and generates an oscillating magnetic signal in the coil. The change in mutual inductance of the coil is picked up by oscillator/detector 22 and results in a change in output 24 indicating a frequency change and in output 26 indicating a voltage change. The magnitude of electrical conductivity (or impedance) of a particular horizontal section of the brain is thus detected. In this embodiment the drive/sensor coil 20 would operably slide on a track 28, so that a series of horizontal sections of the head can be measured. FIG. 4 is a schematic drawing of one possible circuit configuration for oscillator/detector 22. Electronically, the circuit represents a marginally stable Colpitts oscillator whose frequency of oscillation is determined by the tank circuit. Although a Hartley-type oscillator, or similar, would work equally well. The potentiometer tap 30 helps to find the proper circuit resistance external to the tank circuit 32 resistance that is needed for stable oscillation. The tank circuit 32 includes coil 20 and capacitors 34. The amplifier 36 with negative feedback provides stable voltage gain. A DC output 24 is extracted from the demodulator diode 38 which reflects the change in oscillator amplitude. The frequency is measured directly off coil 20 at output 26. When a patient's head is placed through coil 20, eddy currents are induced by the time changing magnetic field generated by drive/sensor coil 20. The eddy currents in turn produce a secondary, though slight, magnetic field whose associated field is coupled back to the drive/sensor coil 20. This produces a change in the coil impedance which changes the resonant amplitude, measured at output 24, and the resonant frequency, measured at output 26, of tank circuit 32. The coil inductances are in the millihenry (mH) range so that resonant frequencies in the hundreds of kHz to several MHz are obtained. In this frequency range, the impedance changes are dominated by conductivity properties and not polarization effects caused by the relative permittivity of the media. The loop drive/sensor loop coil 20, shown in FIG. 3, tends to generate a magnetic field which is concentrated in the plane of the drive/sensor coil and which extends above and below the horizontal plane of the drive/sensor coil. Varying the frequency and the waveform of the magnetic field can produce further spatial discrimination. As shown in FIG. 5, which illustrates the exciting magnetic field strength in the plane of the drive/sensor coil, a change in the frequency of the oscillating magnetic field changes spatial discrimination in the plane of the drive/sensor coil. Higher frequency excitation will increase the magnetic field intensity near the surface of the cranium and a lower frequency will increase the depth of penetration toward the center of the brain. By selectively adjusting the frequency and waveform of the generated magnetic field, using controls 40 and 42 respectively (see FIG. 3) the spatial discrimination provided by the drive/sensor coil can be varied. By observing the outputs from the oscillator detector (24/26) as the frequency and waveform of the exciting magnetic field are change (via controls 40 and 42) an impedance map can be generated and small impedance changes in the brain can be localized. The planar drive/sensor loop technique may be implemented to examine selective slices through the head. The apparatus for selectively examining such slices can be a means 28 shown in FIG. 3 for accurately positioning the drive/sensor loop 20 at a plurality of positions. The outputs (24, 26) resulting from each of the overlapping slices, can be analyzed and the location of higher conductivity areas in the brain tissue can be identified. Alternatively, as shown in FIG. 6, a plurality of drive/sensor coils 20 can be used, with each coil interrogated sequentially. Again, the outputs (24, 26) from each indicates the overall impedance value for that horizontal slice. By looking at a plurality of such slices one can map out localized impedance in the brain. Alternatively, several loop coils can be energized at the same time with opposing magnetic fields to better focus the area of excitation. It is to be understood that such drive/sensor coils may be vertically or horizontally oriented; or, the arrangement may be such that both horizontal and vertical orientations are used to increase spatial resolution. The individual impedance measurements made from each of the plurality of planar loops can be resolved into an overall image of the impedance footprint by known signal processing methods. Alternatively, the planar loop can have an elliptical cross section (e.g., ellipse) to allow its rotation to selectively examine sections around the head. FIGS. 7a and b illustrate the design of the elliptical drive/sensor loop 44. Since the region associated with the smaller axis of the elliptical coil has increased sensitivity to impedance change, as the elliptical coil is rotated and the outputs (24,26) observed with changing orientation of the elliptical coil, a plot can be generated which will assist in localizing high impedance regions within the brain. It is envisioned that a plurality of such elliptical loops may be used sequentially to map brain impedance. FIG. 8 is a block diagram of the apparatus showing the use of a solenoid-type coil 48 for the drive/sensor coil. The solenoid-type coil 48 operates similarly to the loop coil (see FIG. 3), except that the solenoid coil shows a maximum response to the samples within a localized volume at the tip of the solenoid coil approximately equal to the diameter of the solenoid coil while the planar loop shows a response to the higher conductivity portions of the sample in almost any position in the coil plane. The solenoid-type coil may have an air core or may use a metal core to further concentrate the magnetic field and localize the area of observation (i.e., increase the spatial resolution). The solenoid-type coil has a more localized, but limited range and would be more useful to detect physiological changes near the surface of the brain. This makes this embodiment ideal to localize and monitor edematous tissue caused by surface trauma or surface tumors. As with the loop coil, the spatial resolution of the solenoid-type coil can be adjusted by varying the frequency of the exciting magnetic field (via control 40) or varying the waveform characteristics of the magnetic field (via control 42). The radius R of higher field intensity is shown in FIG. 9. As the frequency of the magnetic field increases, the radius R shown in FIG. 9, which represents the region of high magnetic field intensity decreases. FIG. 10 shows a set of solenoid-type coils 48 placed around the head in a bonnet. Each coil is sequentially energized by the oscillator/detector 22 and determines the impedance in the localized area of the brain near the cranium surface. The various impedance measurements thus obtained can be mapped to show overall brain impedance and to localize areas of edematous tissue. It is within the contemplation of this invention to use solenoid-type coils in cooperation with planar coils to obtain a more complete picture of the brain impedance. The embodiments discussed thus far were directed to a monostatic system that uses the same coil as both the transmitter coil and receiver coil. This invention also contemplates the use of a bistatic system in which two coils are used. In the bistatic apparatus, shown in FIG. 11, a first transmitter coil 50 is located on one side of the brain and a second receiver coil 52 is located on the opposite side of the brain. The two coils are connected to an oscillator/detector 54. The transmitter coil 50 excites eddy currents in the brain fluid and matter. The secondary weak magnetic field generated by these eddy currents are detected by receiver coil 52. The bistatic apparatus may use a continuous excitation wave or it may use pulsed excitation. FIG. 12 is a block diagram of the oscillator/detector 54 for use with pulsed excitation. The basic idea behind the pulsed measurement relies on the principal of dispersion. The transmitter would transmit a pulse, not a continuous wave, of magnetic energy. As the pulse travels through the brain, the pulse shape changes because of the dispersive characteristic of brain matter. In effect, dispersion causes different wavelength components of the original pulse to travel at different speeds. Therefore, if different wave components travel at different speeds at any range away from the initial pulse transmission site, the collection of wavelengths are added to give a composite pulse with a different shape. This dispersive characteristic can be designed into a compressed pulse technique whereby the composite pulse can be designed to have a maximum amplitude at a particular range, that is, relying on the dispersive properties of the medium to change the waveform of the transmitted pulse so that it reaches a peak at a designated range. This situation is analogous to a handicapped horse race event where the horses are given a staggered start so that they all end up at the finish line at the same time. The advantage of the compressed pulse technique is that it allows us to concentrate pulse energy at designated ranges, thereby giving us the ability to interrogate designated regions of the brain; that is, we do not get a large sensor response at places other than the designated range. The receiver sensor can receive an output proportional to the change at the designated range by a technique called "range gating", whereby the receiver would only look for a signal at designated times. FIG. 12 is a block diagram of such a pulsed circuit configuration. A pulse modulator 56 creates the desired waveform and generates a repetitive train of pulses. The transmitter 58 amplifies the pulses for suitable transmission by the transmitter coil 50. The timer and duplex switch 60 decides when to energize the transmitter sensor 50. The received signal is sensed by the receiver sensor 52 and sent to the timer and duplex switch 60, which decides when to send the received signal to the receiver circuit 62. In the monostatic configuration, sensor 50 and 52 may be the same coil. The receiver circuit 62 may be the circuit shown in FIG. 4. The RF signal from the receiver circuit 62 is amplified by the RF amplifier 64 and then sent to the mixer 66. The mixer 66 and local oscillator 68 convert the RF signal to an IF signal which is amplified by the IF amplifier 70. The IF amplifier 70 may be a matched filter designed to maximize the signal power from knowledge of the desired signal morphology. The detector 72 extracts the signal from the pulse modulation. The unmodulated signal is then amplified 74, displayed, and analyzed by computer 76. In this manner the impedance in different areas along the axis between the transmitter coil 50 and receiver coil 52 (see FIG. 12) can be measured. It would also be envisioned to have a plurality of transmitter coil/sensor coil pairs (as shown in FIG. 11) and thereby map out three-dimensional images of brain impedance. Obviously many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention maybe practiced otherwise than is specifically described.
An apparatus and method for non-invasively sensing physiological changes in the brain is disclosed. The apparatus and method uses an electromagnetic field to measure localized impedance changes in brain matter and fluid. Various spatial and temporal techniques are used to localize impedance changes in the brain. The apparatus and method has particular application in locating and providing time-trend measurements of the process of brain edema or the process of hydrocephalus.
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